Information you can trust. All content on Veohtu is meticulously researched and written by Thomas Solomon, PhD. He does not sell supplements, recovery products, or ad space, and he has no sponsorships, brand affiliations, or ambassador roles. Everything you read reflects his independent views, shaped solely by peer-reviewed scientific evidence — and that will never change.
The Sports Supplements Tool from Thomas Solomon, PhD.
What are the best supplements for runners, OCR athletes, and endurance training?
Next update coming: July 2026.
Optimal performance is achieved with a well-planned and monitored training load combined with good nutrition, sleep, and rest. Lots of athletes also choose to use supplements. However, sports supplements are a big and confusing business — you can easily get lost and waste a lot of time and money. This free tool is an up-to-date summary of all known scientific evidence determining the effect of sports supplements on exercise performance. It can be used in combination with my Recovery Magic Tool. I’ve designed these resources for scientists, practitioners, coaches, and athletes to help inform their decisions. I aim to keep them up-to-date as new evidence emerges.
Is this your first time using this tool? 
If yes, I strongly recommend reading the intro section below (500 words; 3 min read) because it contains important information about how you can learn to make informed decisions about choosing supplements. However, if you’ve already read the intro below, click the arrow to jump down to the tool.
To quote Louise Burke and John Hawley, “Modern sports nutrition offers a feast of opportunities to assist elite athletes to train hard, optimize adaptation, stay healthy and injury free, achieve their desired physique, and fight against fatigue factors that limit success.”. But, when I think about sports supplements, Ron Maughan’s poetry always rolls through my mind: “If it works, it’s probably banned… If it’s not banned, then it probably doesn’t work… There may be some exceptions.”
Functional claims about a specific product are usually made in line with a specific functional dose of the active ingredient. If a product doesn’t contain a sufficient dose then it definitely won’t have the intended effect. Since the FDA/FSA do not systematically monitor supplements, you will often read “This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.”. So, you need confidence in knowing exactly what’s in the bottle of pills or potion you are taking. And, as an athlete, quality control is essential! Without it, you may harm your health or take a contaminated product. And this is where things start to fall apart… Several reports have found major discrepancies between claimed contents and actual content (e.g. ephedra and CBD supplements), while even some controlled drugs, like the steroid hormone dehydroepiandrosterone (DHEA), have slipped through the net and been sold as dietary supplements. Plus, a 2022 systematic review found that 28% (or 875 out of 3132) supplements contained undeclared substances (including stimulants and anabolic steroids) that would trigger a positive doping test. This is worrying because, according to the NURMI study, ~50% of runners use supplements and a 2007 IAAF/World Athletics report found that ~85% of elite track and field athletes used dietary and/or sports supplements. The supplement business is booming!
“It definitely works!”
I've lost count of how many times I’ve heard social media influencers spew the “I've used this and it was awesome” narrative. Regrettably, such phrases are also spouted from the mouths of “reputable” athletes, coaches, and other practitioners including scientists, nutritionists, psychologists, physiologists, and medical doctors on podcast, radio, and TV interviews when talking about a new pill, potion, or device. Frustratingly, these folks rarely say what “it” works for, what “it” is being compared to, or whether using “it” made them objectively faster, stronger, or healthier. When you see such narratives, think to yourself:
Were appropriate baseline measurements made?
What were the baseline measurements?
When were the baseline measurements followed up?
Did the baseline measurements actually change after the intervention period?
Did the person make any other lifestyle changes during the intervention period?
Is the person being paid or sponsored to promote the product? And, so on…
To bring clarity where there is obscurity and help you understand whether “it” might actually improve performance and/or recovery, I’ve dug into all known scientific evidence on this topic and created a free resource to help inform your decisions.
High-quality robust evidence comes from studies with a randomised controlled trial (RCT)The “gold standard” approach for determining whether a treatment has a causal effect on an outcome of interest. In such a study, a sample of people representing the population of interest is randomised to receive the treatment or a no-treatment placebo (control), and the outcome of interest is measured before and after the exposure to treatment/control. design. But, “cherry-picking” a study to confirm a bias is not a valid pursuit for informing practice. A systematic reviewA systematic review answers a specific research question by systematically collating all known experimental evidence, which is collected according to pre-specified eligibility criteria. A systematic review helps inform decisions, guidelines, and policy. examines all the “cherries” in a standardised way and, when the studies included in a systematic review are of high enough quality, a meta-analysisA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all studies of that treatment. of all the available data can be completed. This calculates an overall effect sizeAn effect size is a quantitative measure of the magnitude of a relationship or difference between groups in a study. Unlike p-values, effect sizes show how large or meaningful that effect is. Common effect size measures include Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients. along with a 95% confidence interval (CI)A measure of uncertainty used in Frequentist statistics. The 95% confidence interval is a plausible range of values within which the true value (e.g., the true treatment effect) would be found 95% of the time if the data was repeatedly collected in different samples of people. If this range of values (the confidence interval) crosses zero, there is little confidence in the effect. (the range of values the true effect size is likely to be found if the intervention is repeated) and a heterogeneity score or I-squared (I2) valueI-squared (I2) is a statistic used in meta-analysis to quantify the percentage of variation across studies that is due to heterogeneity rather than chance. A low I2 value (25-50%) indicates that the findings are relatively consistent between studies, whereas a high I2 value (>75%) suggests considerable variability among the study results, which may affect the reliability of the overall conclusions. (how variable the effect is). In simple words, a meta-analysis analyses all the “cherries” simultaneously to produce a useable effect size based on all available scientific evidence, enabling good decisions to be made.
So, when I say that “I’ve dug into all known scientific evidence”, I mean that I’ve read all known meta-analyses on PubMed and summarised the evidence in this free resource: the Sports Supplements Tool.
But, before making any decisions, always conduct a cost-benefit analysis, where “cost” includes a combination of financial costs, time costs, moral costs, risk of contamination, potential performance impairment, and harm to health. For example:
If there is no benefit, there is no point in using the supplement.
If there is a benefit and no (or little) cost, use the supplement; you’d be foolish not to.
If the cost outweighs the benefit, do not proceed.
When making this kind of cost-benefit analysis, always remember that:
Taking a supplement does not “make” an athlete.
A supplement does not replace training.
A dietary supplement does not replace food.
There is no such thing as “exercise in a pill”.
It is also important to know that if you use supplements of any kind and/or prescription or over-the-counter drugs, you are also putting yourself at an increased risk of a positive test because they can contain prohibited substances. Minimise this risk by taking the following steps:
Educate yourself by completing European Athletics’ I Run Clean certification.
Familiarise yourself with the rules of your sport and with WADA’s prohibited list, which is updated every January.
If you are using ANY sports (or dietary) supplement, ensure it has been independently tested for prohibited substances by Informed Sport (or similar), and ensure you supplement contains what it is supposed to contain (see LabDoor) → If in doubt, spit it out!
If you are using ANY over-the-counter or prescribed drugs, ALWAYS know what you are taking and get in the habit of cross-checking the Global DRO to help determine whether you need a TUE (therapeutic use exemption).
And, once you’ve chosen a supplement, check the label to make sure that it contains the ingredient you want and doesn’t contain ingredients you don’t want (see this very useful image from Examine.com to help out with that process).
And, finally… Always remember that:
You are the only person responsible for what goes into your body.
Ignorance is not an excuse.
Stay educated. Be informed. Encourage others to do the same.
OK… You’re now ready for some science.
The information I provide is not medical advice. Caffeine can have side effects and might interact with other drugs, nutrients, and medical conditions (see here). If you are unsure, always consult your doctor to ensure that a specific supplement is safe for you to use.
What is caffeine?
Caffeine (1,3,7-trimethylxanthine) is a psychoactive stimulant. In simple terms, it blocks adenosine receptors in the brain. Adenosine usually tells your body to relax and dial things down; caffeine gets in the way of that message so “go” chemicals like dopamine can keep doing their thing. Caffeine may also influence calcium transport in muscle cells, but the main show is in the central nervous system.
Side effects can include a faster heart rate, palpitations, headache, trouble sleeping, peeing more, jitters, and stomach upset. If you notice any of these before, during, or after training or racing, you’ve probably gone a bit heavy on the dose. Given those side effects — and the media headlines about super-sugary energy drinks — it’s fair to ask: is caffeine dangerous?
A 2017 systematic review concluded that “up to 400 milligrams of caffeine per day in healthy adults is not associated with overt adverse effects” and that up to 300 milligrams per day is generally safe in healthy pregnant women.
A 2017 umbrella review of meta-analysesA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment. found that “coffee consumption seems generally safe within usual levels of intake”. In sport settings, a 2022 systematic review reported that athletes should weigh both benefits and risks and that “around 3 milligrams per kilogram bodyweight may balance performance gains with fewer side effects”.
And in everyday life, a 2023 randomised controlled crossover trial with continuous ECG monitoring found that drinking more caffeinated coffee than usual may increase premature ventricular contractions, but did not the number of unusual heart rhythms (atrial arrhythmias) in healthy adults (Marcus et al.).
So, the bottom line, caffeine is generally safe for most people if used within the recommended amounts.
Therefore, it is no surprise that a lot of people use caffeine as a way to start (and continue) their day. Bonjour coffee! The NHANESstudy found that roughly 89% of US adults consume caffeine daily, and a 2022 survey found that 85% of endurance athletes reported daily caffeine consumption and 41% reported multiple daily caffeine intake, though fewer (24%) used purpose-made caffeine supplements during training or racing. So…
What is the scientific evidence on caffeine’s impact on athletic performance?
Taking caffeine 60 to 90 minutes before exercise — or before and during exercise — lowers the RPERPE means “rating of perceived exertion,” a simple 0 to 10 or 6 to 20 scale for how hard the effort feels. Lower RPE means the same work feels easier. during exercise (moderate effect sizeAn effect size is a quantitative measure of the magnitude of a relationship or difference between groups in a study. Unlike p-values, effect sizes show how large or meaningful that effect is. Common effect size measures include Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients.), including during long, hard efforts (moderate to large effect size).
It improves endurance performance in time trials and time-to-exhaustion tests (moderate effect size), increases muscle strength (moderate effect), helps raise jump height (small effect), and boosts maximal power in very short efforts (small to moderate effect).
In the heat (about 30 degrees Celsius or hotter), pre-exercise caffeine still helps with endurance exercise with only a trivial extra heat stress to core temperature changes from the workout itself.
In skill-based and team sports, caffeine can shave time off agility tests (moderate effect) and increase total running distance, sprint running distance, and the number of sprints during matches (small to moderate effects).
Most performance studies test people when they’re fresh. We don’t yet know if the same boost happens when tests come after a fatiguing bout of exercise.
The effect is usually bigger for aerobic-type efforts than for pure “anaerobic” bursts.
Adding caffeine to carbohydrate during endurance exercise gives a small extra performance boost compared with carbohydrate alone.
Female participants are under-represented in caffeine research (see here and here). Some meta-analyses report performance benefits in females (see here, here, and here) but further research is needed to tailor advice.
Caffeine metabolism depends mostly on the enzyme cytochrome P450 1A2, coded by the CYP1A2 gene. Sorry, that’s a bit jargonny, but people with different CYP1A2 genotypes metabolize caffeine faster or slower. That might change the performance boost — some studies find “fast” metabolizers (AA genotype) benefit more — but results are small and inconsistent. More research is needed.
Caffeine mouth-rinsing has mixed results. Some studies say “yay”, but many studies say “nay” for performance. Swallowing caffeine is the reliable route.
You might wonder: Does coffee have the same performance-enhancing effect as isolated caffeine? When coffee vs. pure caffeine is matched for caffeine dose, coffee works similarly (see ISSN position stand 2023). The headache is knowing the actual amount of caffeine in your coffee cup. The “average” cup of coffee is said to contain approximately 100 milligrams of caffeine. Since the performance-enhancing dose of caffeine is within 3 to 6 milligrams per kg bodyweight, 2-cups of coffee (~200 milligrams of caffeine) “should” provide ~3 milligrams per kg of caffeine for a person weighing 70 kg. However, bean type, brew method, and cup size swing the dose wildly, so 100 mg per cup is a (bad) guess at best. For training, the “2 cups = performance boost” rule of thumb can be fine. For race day, a sports product with a known caffeine amount is safer.
You might also wonder: Does chronic caffeine use alter caffeine’s acute performance-enhancing effects? A 2019 review argued that habitual caffeine may blunt the boost a little, but slightly higher acute doses can restore it. They authors also noted that short-term caffeine/coffee withdrawal before a key event doesn’t seem to add extra benefit from supplemental caffeine. They also made the highly relevant point that “Given the individual response to caffeine, both in terms of habituation and ergogenesis, athletes should experiment with various doses and timing strategies when using caffeine to enhance performance”. In other words, always experiment with dose and timing in training before unleashing your caffeine buzz on race day.
Caffeine can reduce sleep quality and duration (see here and here). To protect sleep, aim to finish coffee about 9 hours before bedtime and caffeine-containing supplements about 13 hours before bedtime (see here).
Anti-doping note: caffeine is widely used, socially accepted, generally safe, and hard to regulate. Yes, caffeine is so potent it might be banned if discovered today but caffeine-containing plants have been used by humans since the dawn of breakfast. Consequently, in the eyes of World Anti-Doping Agency (WADA), caffeine is a a “monitored” substance but does not ban it. Always check your sport’s rules and the latest WADA prohibited list and your event’s policies.
If you choose to use caffeine, a reasonable dose is:
3 to 6 milligrams (mg) of caffeine per kg body weight 30 to 60-minutes before a session or race.
Note: this is based on effective doses used in research. Click here to see some examples of caffeine-containing gels).
That’s roughly 1 to 2 cups of coffee — but the true caffeine in a cup varies a lot by bean, brew, and cup size.
Taking more doesn’t necessarily mean a bigger effect; taking more increases the risk of side effects.
Can caffeine enhance athletic performance?
Taking caffeine before a race or session is likely to improve performance during endurance, strength, and speed-based events.
Taking caffeine during exercise is also likely to boost performance, but there is insufficient evidence to recommend a specific repeated caffeine dosing regimen during exercise.
The effect sizeAn effect size is a standardized measure of the magnitude of an effect of an intervention. Unlike p-values, effect sizes show how large the effect is and indicate how meaningful it might be. Common effect size measures include standardised mean difference (SMD), Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients. ranges from small (for short, high/maximal-intensity efforts) to moderate/large (for endurance).
The effects of caffeine appear to be similar between trained athletes and untrained folks, and between males and females.
These conclusions are based on a moderateA moderate quality of evidence means that, in general, studies in this field have some limitations. This could be due to somewhat inconsistent effects between studies, a moderate range of effect sizes between studies, and/or a moderate risk of bias (caused by a small to medium number of studies, small to medium numbers of participants, partially described randomization processes, some missing data, some inappropriate methods/statistics). When the quality of evidence is moderate, there is some doubt and only moderate confidence in the overall effect of an intervention, and future studies could change overall conclusions. The best way to improve the quality of evidence is for scientists to conduct large, well-controlled, high-quality randomized controlled trials. to high quality of evidenceA high quality of evidence means that, in general, there is a small range of effect sizes between studies, effects are consistent, and there is a low risk of bias (due to a large number of studies, large numbers of participants, good study designs, appropriate methods, etc). When the quality of evidence is high, there is a high level of confidence that the overall effect size reflects the true effect.: effects are fairly consistent between studies, and there’s a large number of well-designed studies. Consequently, there’s a high level of confidence that the overall effect sizes reported in meta-analysesA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment. reflect the true effect of caffeine.
To minimise the risk of consuming a supplement that contains prohibited substances, only choose products that have been independently tested (e.g., Informed Sport). And, remember: Supplements do not make athletes and do not replace training; they're just the icing on a very well-baked cake. Before reaching for pills and potions, optimise your training load and dial in your sleep, nutrition, and rest.
How to use this: In training, try 3 to 6 milligrams per kilogram bodyweight (roughly 200 to 400 milligrams in a 70 kg person) 30 to 60 minutes pre-session and note your response (performance gains, gut issues, and sleep problems). For race day, prefer products with known caffeine amounts rather than guessing with coffee. If you’re a habitual caffeine user, you might need the upper end of that range — but don’t chase more, because side effects climb quickly. To protect sleep, finish coffee at least 9 hours before bed and caffeine-containing supplements at least 13 hours before bed. And, keep it legal: always check your event’s rules and the current WADA prohibited list.
Full list of meta-analyses examining caffeine for performance.
Here are the meta-analyses I've summarised above:
Effects of acute caffeine intake on muscular power during resistance exercise: a systematic review and meta-analysis. Xiao et al. (2025) Front Nutr.
The Effect of Consuming Caffeine Before Late Afternoon/Evening Training or Competition on Sleep: A Systematic Review with Meta-Analysis. Kocak et al. (2025) Sports (Basel).
Caffeine Placebo Effect in Sport and Exercise: A Systematic Review. Vega-Muñoz et al. (2024) Nutrients.
Exploring the ergogenic potential of carbohydrate-caffeine combined mouth rinse on exercise and cognitive performance: a systematic review. Poon et al. (2024) Appl Physiol Nutr Metab.
Effect of caffeine ingestion on time trial performance in cyclists: a systematic review and meta-analysis. Chen et al. (2024) J Int Soc Sports Nutr.
Effects of Acute Ingestion of Caffeine Capsules on Muscle Strength and Muscle Endurance: A Systematic Review and Meta-Analysis. Wu et al. (2024) Nutrients.
Can caffeine improve your performance? Psychophysiological effects – A systematic review. Velásquez et al. (2024) Nutr Hosp.
Effect of Acute Caffeine Intake on Fat Oxidation Rate during Fed-State Exercise: A Systematic Review and Meta-Analysis. Fernández-Sánchez J, Trujillo-Colmena D, Rodríguez-Castaño A, Lavín-Pérez AM, Del Coso J, Casado A, Collado-Mateo D. Nutrients (2024)
Effects of Acute Ingestion of Caffeine Capsules on Muscle Strength and Muscle Endurance: A Systematic Review and Meta-Analysis. Wu W, Chen Z, Zhou H, Wang L, Li X, Lv Y, Sun T, Yu L. Nutrients (2024)
Caffeine, CYP1A2 Genotype and Exercise Performance: A Systematic Review and Meta-analysis. Barreto, Gabriel; Esteves, Gabriel P; Marticorena, Felipe; Oliveira, Tamires N; Grgic, Jozo; Saunders, Bryan. Med Sci Sports Exerc (2023) The effect of caffeine on subsequent sleep: A systematic review and meta-analysis. Carissa Gardiner, Jonathon Weakley, Louise M. Burke, Gregory D. Roach, Charli Sargent, Nirav Maniar, Andrew Townshend, Shona L. Halson. Sleep Med Rev (2023)
International society of sports nutrition position stand: coffee and sports performance. Lowery et al. (2023) J Int Soc Sports Nutr
Effects of Caffeine Intake on Endurance Running Performance and Time to Exhaustion: A Systematic Review and Meta-Analysis. Ziyu Wang, Bopeng Qiu, Jie Gao, Juan Del Coso. Nutrients (2022)
Acute Effects of Caffeine on Overall Performance in Basketball Players-A Systematic Review. Anja Lazić, Miodrag Kocić, Nebojša Trajković, Cristian Popa, Leonardo Alexandre Peyré-Tartaruga, Johnny Padulo. Nutrients (2022)
Effect of Pre-Exercise Caffeine Intake on Endurance Performance and Core Temperature Regulation During Exercise in the Heat: A Systematic Review with Meta-Analysis. Catherine Naulleau, David Jeker, Timothée Pancrate, Pascale Claveau, Thomas A Deshayes, Louise M Burke, Eric D B Goulet. Sports Med (2022)
Exploring the minimum ergogenic dose of caffeine on resistance exercise performance: A meta-analytic approach. Jozo Grgic. Nutr (2022)
Risk or benefit? Side effects of caffeine supplementation in sport: a systematic review. Jefferson Gomes de Souza, Juan Del Coso, Fabiano de Souza Fonseca, Bruno Victor Corrêa Silva, Diego Brito de Souza, Rodrigo Luiz da Silva Gianoni, Aleksandra Filip-Stachnik, Julio Cerca Serrão, João Gustavo Claudino. Eur J Nutr (2022)
Effects of acute caffeine intake on combat sports performance: A systematic review and meta-analysis. Javier Diaz-Lara, Jozo Grgic, Daniele Detanico, Javier Botella, Sergio L Jiménez, Juan Del Coso. Crit Rev Food Sci Nutr (2022)
Effects of caffeine on rate of force development: A meta-analysis. Jozo Grgic, Pavle Mikulic. Scand J Med Sci Sports (2022)
Supplementation and Performance for Wheelchair Athletes: A Systematic Review. Andreia Bauermann, Karina S G de Sá, Zilda A Santos, Anselmo A Costa E Silva. Adapt Phys Activ Q (2022)
Acute caffeine supplementation and live match-play performance in team-sports: A systematic review (2000-2021). Adriano Arguedas-Soley, Isobel Townsend, Aaron Hengist, James Betts. J Sports Sci (2022)
Interaction Between Caffeine and Creatine When Used as Concurrent Ergogenic Supplements: A Systematic Review. Sara Elosegui, Jaime López-Seoane, María Martínez-Ferrán, Helios Pareja-Galeano. Int J Sport Nutr Exerc Metab (2022)
Synergy of carbohydrate and caffeine ingestion on physical performance and metabolic responses to exercise: A systematic review with meta-analysis. Jaime López-Seoane, Marta Buitrago-Morales, Sergio L Jiménez, Juan Del Coso, Helios Pareja-Galeano. . Crit Rev Food Sci Nutr (2022)
Does Caffeine Increase Fat Metabolism? A Systematic Review and Meta-Analysis. Scott A. Conger, Lara M. Tuthill, Mindy L. Millard-Stafford. Int J Sport Nutr Exerc Metab (2022)
Effects of Caffeine Intake on Endurance Running Performance and Time to Exhaustion: A Systematic Review and Meta-Analysis. Ziyu Wang, Bopeng Qiu, Jie Gao, and Juan Del Coso. Nutrients (2022)
Acute Effects of Caffeine Supplementation on Physical Performance, Physiological Responses, Perceived Exertion, and Technical-Tactical Skills in Combat Sports: A Systematic Review and Meta-Analysis. Slaheddine Delleli, Ibrahim Ouergui, Hamdi Messaoudi, Khaled Trabelsi, Achraf Ammar, Jordan M. Glenn and Hamdi Chtourou. Nutrients (2022)
Effects of caffeine ingestion on cardiopulmonary responses during a maximal graded exercise test: a systematic review with meta-analysis and meta-regression. Alisson Henrique Marinho, João Paulo Lopes-Silva, Gislaine Cristina-Souza, Filipe Antônio de Barros Sousa, Thays Ataide-Silva, Adriano Eduardo Lima-Silva, Gustavo Gomes de Araujo, Marcos David Silva-Cavalcante. Crit Rev Food Sci Nutr (2022)
Effects of caffeine chewing gum supplementation on exercise performance: A systematic review and meta-analysis. G Barreto, L M R Loureiro, C E G Reis, B Saunders. Eur J Sport Sci (2022)
Can I Have My Coffee and Drink It? A Systematic Review and Meta-analysis to Determine Whether Habitual Caffeine Consumption Affects the Ergogenic Effect of Caffeine. Arthur Carvalho, Felipe Miguel Marticorena, Beatriz Helena Grecco, Gabriel Barreto, Bryan Saunders. Sports Med (2022)
Effects of caffeine on isometric handgrip strength: A meta-analysis. Jozo Grgic. Clin Nutr ESPEN (2022)
International society of sports nutrition position stand: caffeine and exercise performance. Nanci S Guest, Trisha A VanDusseldorp, Michael T Nelson Jozo Grgic, Brad J Schoenfeld, Nathaniel D M Jenkins, Shawn M Arent, Jose Antonio, Jeffrey R Stout, Eric T Trexler, Abbie E Smith-Ryan, Erica R Goldstein, Douglas S Kalman, Bill I Campbell. J Int Soc Sports Nutr (2021)
Ergogenic Effects of Acute Caffeine Intake on Muscular Endurance and Muscular Strength in Women: A Meta-Analysis. Jozo Grgic, Juan Del Coso. Int J Environ Res Public Health (2021)
Does Acute Caffeine Supplementation Improve Physical Performance in Female Team-Sport Athletes? Evidence from a Systematic Review and Meta-Analysis. Alejandro Gomez-Bruton, Jorge Marin-Puyalto, Borja Muñiz-Pardos, Angel Matute-Llorente, Juan Del Coso, Alba Gomez-Cabello, German Vicente-Rodriguez, Jose A Casajus, Gabriel Lozano-Berges. Nutrients (2021)
Does Acute Caffeine Supplementation Improve Physical Performance in Female Team-Sport Athletes? Evidence from a Systematic Review and Meta-Analysis. Alejandro Gomez-Bruton, Jorge Marin-Puyalto, Borja Muñiz-Pardos, Angel Matute-Llorente, Juan Del Coso, Alba Gomez-Cabello, German Vicente-Rodriguez, Jose A Casajus, Gabriel Lozano-Berges. Nutrients (2021)
Caffeinated Drinks and Physical Performance in Sport: A Systematic Review. Sergio L Jiménez, Javier Díaz-Lara, Helios Pareja-Galeano, Juan Del Coso. Nutrients (2021)
Ergogenic Effects of Acute Caffeine Intake on Muscular Endurance and Muscular Strength in Women: A Meta-Analysis. Grgic J, Del Coso J. Int J Environ Res Public Health (2021)
Is caffeine mouth rinsing an effective strategy to improve physical and cognitive performance? A systematic review. da Silva WF, Lopes-Silva JP, Camati Felippe LJ, Ferreira GA, Lima-Silva AE, Silva-Cavalcante MD. Crit Rev Food Sci Nutr (2021)
Caffeine and Cognitive Functions in Sports: A Systematic Review and Meta-Analysis. Lorenzo Calvo J, Fei X, Domínguez R, Pareja-Galeano H. Nutrients (2021)
Nonplacebo Controls to Determine the Magnitude of Ergogenic Interventions: A Systematic Review and Meta-analysis.
Marticorena FM, Carvalho A, de Oliveira LF, Dolan E, Gualano B, Swinton P, Saunders B. Med Sci Sports Exerc (2021)
CYP1A2 genotype and acute ergogenic effects of caffeine intake on exercise performance: a systematic review. Grgic J, Pickering C, Del Coso J, Schoenfeld BJ, Mikulic P. Eur J Nutr (2021)
Effects of diet interventions, dietary supplements, and performance-enhancing substances on the performance of CrossFit-trained individuals: A systematic review of clinical studies. Dos Santos Quaresma MVL, Guazzelli Marques C, Nakamoto FP. Nutrition (2021)
Effect of Acute Caffeine Intake on the Fat Oxidation Rate during Exercise: A Systematic Review and Meta-Analysis. Collado-Mateo D, Lavín-Pérez AM, Merellano-Navarro E, Coso JD. Nutrients (2020)
Effect of Supplements on Endurance Exercise in the Older Population: Systematic Review. Martínez-Rodríguez A, Cuestas-Calero BJ, Hernández-García M, Martíez-Olcina M, Vicente-Martínez M, Rubio-Arias JÁ. Int J Environ Res Public Health (2020)
The Effects of Caffeine Mouth Rinsing on Exercise Performance: A Systematic Review. Ehlert AM, Twiddy HM, Wilson PB. Int J Sport Nutr Exerc Metab (2020)
Effects of caffeine supplementation on muscle endurance, maximum strength, and perceived exertion in adults submitted to strength training: a systematic review and meta-analyses. Ferreira TT, da Silva JVF, Bueno NB. Crit Rev Food Sci Nutr (2020)
Acute Effects of Caffeine Supplementation on Movement Velocity in Resistance Exercise: A Systematic Review and Meta-analysis. Raya-González J, Rendo-Urteaga T, Domínguez R, Castillo D, Rodríguez-Fernández A, Grgic J. Sports Med (2020)
The Effects of Caffeine Ingestion on Measures of Rowing Performance: A Systematic Review and Meta-Analysis. Grgic J, Diaz-Lara FJ, Coso JD, Duncan MJ, Tallis J, Pickering C, Schoenfeld BJ, Mikulic P. Nutrients (2020)
Is Caffeine Recommended Before Exercise? A Systematic Review To Investigate Its Impact On Cardiac Autonomic Control Via Heart Rate And Its Variability. Benjamim CJR, Kliszczewicz B, Garner DM, Cavalcante TCF, da Silva AAM, Santana MDR, Valenti VE. J Am Coll Nutr (2020)
Isolated effects of caffeine and sodium bicarbonate ingestion on performance in the Yo-Yo test: A systematic review and meta-analysis. Grgic J, Garofolini A, Pickering C, Duncan MJ, Tinsley GM, Del Coso J. J Sci Med Sport (2020)
Wake up and smell the coffee: caffeine supplementation and exercise performance-an umbrella review of 21 published meta-analyses. Grgic J, Grgic I, Pickering C, Schoenfeld BJ, Bishop DJ, Pedisic Z. Br J Sports Med (2020)
Effect of Caffeine Supplementation on Sports Performance Based on Differences Between Sexes: A Systematic Review. Juan Mielgo-Ayuso, Diego Marques-Jiménez, Ignacio Refoyo, Juan Del Coso, Patxi León-Guereño, Julio Calleja-González. Nutrients (2019)
The effects of caffeine ingestion on isokinetic muscular strength: A meta-analysis. Grgic J, Pickering C. J Sci Med Sport (2019)
Caffeine Supplementation and Physical Performance, Muscle Damage and Perception of Fatigue in Soccer Players: A Systematic Review. Mielgo-Ayuso J, Calleja-Gonzalez J, Del Coso J, Urdampilleta A, León-Guereño P, Fernández-Lázaro D. Nutrients (2019)
Effects of acute ingestion of caffeine on team sports performance: a systematic review and meta-analysis. Salinero JJ, Lara B, Del Coso J. Res Sports Med (2019)
Correction to: The Effect of Acute Caffeine Ingestion on Endurance Performance: A Systematic Review and Meta-Analysis. Southward K, Rutherfurd-Markwick KJ, Ali A. Sports Med (2018). Note: this article was originally published here but contained errors that were corrected in this revised version.
Effects of Coffee Components on Muscle Glycogen Recovery: A Systematic Review. Loureiro LMR, Reis CEG, da Costa THM. Int J Sport Nutr Exerc Metab (2018)
Caffeine and Physiological Responses to Submaximal Exercise: A Meta-Analysis. Glaister M, Gissane C. Int J Sports Physiol Perform (2018)
Caffeine ingestion enhances Wingate performance: a meta-analysis. Grgic J. Eur J Sport Sci (2018)
Coffee, caffeine, and sleep: A systematic review of epidemiological studies and randomized controlled trials. Ian Clark, Hans Peter Landolt. Sleep Med Rev (2017)
Acute effects of caffeine-containing energy drinks on physical performance: a systematic review and meta-analysis. Souza DB, Del Coso J, Casonatto J, Polito MD. Eur J Nutr (2017)
A systematic review of the efficacy of ergogenic aids for improving running performance. Schubert MM, Astorino TA. J Strength Cond Res (2013)
Does caffeine added to carbohydrate provide additional ergogenic benefit for endurance? Conger SA, Warren GL, Hardy MA, Millard-Stafford ML. Int J Sport Nutr Exerc Metab (2011)
Efficacy of acute caffeine ingestion for short-term high-intensity exercise performance: a systematic review. Astorino TA, Roberson DW. J Strength Cond Res (2010)
Effect of caffeine on sport-specific endurance performance: a systematic review. Ganio MS, Klau JF, Casa DJ, Armstrong LE, Maresh CM. J Strength Cond Res (2009)
Effects of caffeine ingestion on rating of perceived exertion during and after exercise: a meta-analysis. Doherty M, Smith PM. Scand J Med Sci Sports (2005 )
Consult WADA’s prohibited list.
Cross-check your meds against the Global DRO drug reference list.
Only choose supplements that have been independently tested by Informed Sport or LabDoor. 
You are the only person responsible for what goes in your body. Ignorance is not an excuse! Stay educated. Be informed.
Nail your daily nutrition habits first, layer specific sports nutrition on top of that, and then start to consider supplements.
The information I provide is not medical advice. Taurine can have side effects and might interact with other drugs, nutrients, and medical conditions (see here). If you are unsure, always consult your doctor to ensure that a specific supplement is safe for you to use.
What is taurine?
Taurine is an amino acid and the body makes it from another amino acid (called cysteine), but we also get it from food — mostly meat, dairy, seafood, and algae-containing foods like seaweed (see here and here). Unlike some amino acids, taurine doesn’t build proteins. Instead, it helps control how water and electrolytes move in and out of cells, supports cell membrane stability, and keeps calcium handling on track during muscle contractions. Those jobs matter for both the heart and skeletal muscle. For a deep dive into the physiology of taurine, see Lambert et al. 2014.
Because taurine helps with calcium control and contraction, people often assume it could improve strength or endurance. That’s one reason you’ll see it listed on energy drink cans (hello Red Bull). But energy drink labels and science aren’t the same thing, so let’s look at the evidence.
What is the scientific evidence on taurine’s impact on athletic performance?
Taurine appears safe at amounts used in studies, and typical energy drinks contain much less than doses linked with adverse events (see here and here). Clinical studies have tested about 3 to 10 grams per day and reported good short-term tolerance. That said, there’s no evidence-informed “performance dose” for runners or endurance athletes.
One meta-analysisA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment. (see Waldron et al. 2018) reported that taking taurine before exercise might slightly extend time-to-exhaustion. The effect looked clearer in people with heart failure and was fuzzy in healthy folks and athletes. It’s also unknown whether people who eat very little taurine get more benefit — we just don’t have that answer yet.
A meta-analysis (Souza et al. 2017) of energy drinks found a positive link between higher taurine dose and better performance when the drink was taken before exercise — but those drinks also contained caffeine, so you can’t tell what taurine did on its own. A separate meta-analysis by Waldron et al. 2018 that looked specifically at taurine dose did not find a dose-response for performance.
Overall, the current quality of evidence is low, high-quality dose-response studies are lacking, and high-quality randomised controlled trials are urgently needed.
Can taurine enhance athletic performance?
Taurine is unlikely to improve performance.
The lack of benefit appears to be similar between trained athletes and untrained folks, and between males and females; however, further research is needed in females because they are underrepresented among studies in this field.
Keep in mind: due to the low quality of evidenceA low quality of evidence means that, in general, studies in this field have several limitations. This could be due to inconsistency in effects between studies, a large range of effect sizes between studies, and/or a high risk of bias (caused by inappropriate controls, a small number of studies, small numbers of participants, poor/absent randomization processes, missing data, inappropriate methods/statistics). When the quality of evidence is low, there is more doubt and less confidence in the overall effect of an intervention, and future studies could easily change overall conclusions. The best way to improve the quality of evidence is for scientists to conduct large, well-controlled, high-quality randomized controlled trials. from existing clinical studies, the overall effect sizeAn effect size is a standardized measure of the magnitude of an effect of an intervention. Unlike p-values, effect sizes show how large the effect is and indicate how meaningful it might be. Common effect size measures include standardised mean difference (SMD), Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients. is unclear.
Additional high-quality randomised controlled trialsThe “gold standard” approach for determining whether a treatment has a causal effect on an outcome of interest. In such a study, a sample of people representing the population of interest is randomised to receive the treatment or a no-treatment placebo (control), and the outcome of interest is measured before and after exposure to the treatment and control. are needed to formulate evidence on the effects of taurine on performance in humans.
The nice part: taurine doesn't appear to hurt performance. So, if you like it and believe it works for you, give it a whirl. But, remember that time and money spent trying to improve your performance with something that has no obvious benefit might be better spent optimising your training load, sleep habits, and dietary/nutritional choices.
To minimise the risk of consuming a supplement that contains prohibited substances, only choose products that have been independently tested (e.g., Informed Sport). And, remember: Supplements do not make athletes and do not replace training; they're just the icing on a very well-baked cake. Before reaching for pills and potions, optimise your training load and dial in your sleep, nutrition, and rest.
How to use this: If you still want to experiment, keep expectations low. There’s no proven performance dose. Some clinical studies used about 3 to 10 grams per day, but that was for safety, not performance. Track your training and results for a few weeks, then decide if it’s worth continuing.
The information I provide is not medical advice. Taurine can have side effects and might interact with other drugs, nutrients, and medical conditions (see here). If you are unsure, always consult your doctor to ensure that a specific supplement is safe for you to use.
Full list of meta-analyses examining taurine for performance.
Here are the meta-analyses I've summarised above:
Does One Shot Work? The Acute Impact of a Single Taurine Dose on Exercise Performance: A Meta-Analytic Review. Denget al. (2025) Scand J Med Sci Sports.
The Dose Response of Taurine on Aerobic and Strength Exercises: A Systematic Review. Chen Q, Li Z, Pinho RA, Gupta RC, Ugbolue UC, Thirupathi A, Gu Y. Front Physiol (2021).
The Effects of an Oral Taurine Dose and Supplementation Period on Endurance Exercise Performance in Humans: A Meta-Analysis. Mark Waldron, Stephen David Patterson, Jamie Tallent, Owen Jeffries. Sports Med (2018)
Acute effects of caffeine-containing energy drinks on physical performance: a systematic review and meta-analysis. Diego B Souza, Juan Del Coso, Juliano Casonatto, Marcos D Polito. Eur J Nutr (2017)
Consult WADA’s prohibited list.
Cross-check your meds against the Global DRO drug reference list.
Only choose supplements that have been independently tested by Informed Sport or LabDoor. You are the only person responsible for what goes in your body. Ignorance is not an excuse! Stay educated. Be informed.
Nail your daily nutrition habits first, layer specific sports nutrition on top of that, and then start to consider supplements.
The information I provide is not medical advice. Creatine can have side effects and might interact with other drugs, nutrients, and medical conditions (see here). If you are unsure, always consult your doctor to ensure that a specific supplement is safe for you to use.
What is creatine?
Creatine is a naturally occurring compound your body makes from the amino acids arginine and glycine. It isn’t built into proteins and it isn’t coded by your genes. Instead, creatine helps your cells manage energy, and about 95% of it lives in your muscles.
Your body makes some creatine from the amino acids, arginine and glycine, but also breaks it down to creatinine, which you pee out. That means you also need creatine from food to keep levels topped up. Eating meat (inc. red meat, chicken, pork, etc.), fish (e.g., salmon), and seafood can provide it. If you don’t eat those foods, supplements can fill the gap because creatine in supplements is chemically synthesised and not extracted from meat (and, strict plant-based folks can simply choose a plant-based capsule).
During exercise, your muscles chew through adenosine triphosphate (ATP), which is the cell’s “energy coin”. At very high power outputs, ATP from carbohydrate and fat isn’t made fast enough. That’s where phosphocreatine (PCr) comes in. Breaking down PCr into creatine (Cr) frees a phosphate molecule (Pi) that helps rebuild ATP quickly — basically a nitro button for brief, all-out efforts.
ATP resynthesis: PCr → Cr + Pi then ADP + Pi → ATP
So if your muscles hold more creatine, you can produce more phosphocreatine and resupply ATP faster during maximal-effort, anaerobic or sprint-type work. Because daily creatine supplementation increases muscle creatine levels, creatine has become one of the most studied — and most popular — sports supplements. So…
What is the scientific evidence on creatine’s impact on athletic performance?
Creatine supplementation is safe for most people. That said, folks with asthma, immune dysfunction, and/or kidney or liver conditions, should consult their doctor before considering a creatine supplement.
Creatine does not improve training-related gains in endurance performance (for example, time trials or time-to-exhaustion). In fact, one meta-analysisA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment. even reports small reductions in the training-induced improvements in V̇O2maxV̇O2max is the maximal rate of oxygen consumption your body can achieve during exercise. It is a measure of cardiorespiratory fitness and indicates the size of your engine, i.e., your maximal aerobic power, which contributes to endurance performance. (small effect sizeAn effect size is a quantitative measure of the magnitude of a relationship or difference between groups in a study. Unlike p-values, effect sizes show how large or meaningful that effect is. Common effect size measures include Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients.).
Creatine improves gains in maximal strength and in sets taken to failure that last under about 3 minutes (small to moderate effect sizes).
Creatine improves high-intensity “anaerobic” performance, such as 30-second Wingate tests (large effect sizes).
In older adults (60 and older), combining creatine with strength training helps preserve muscle mass (large effect sizes), muscle strength (small to moderate), and functional ability (for example, chair sit-to-stand; large) more than training alone — a handy add-on for healthy ageing.
Early evidence suggests creatine might help short-term memory and reasoning in healthy people (Avgerinos et al. 2018). However, further randomised controlled trials are needed, especially in older populations, to make firm conclusions.
Some studies note more stomach upset when caffeine and creatine are taken together, and chronic caffeine during a creatine loading phase might blunt creatine’s benefits (although the acute effect of caffeine seems intact). However, better trials are needed to fully map the caffeine-creatine interactions.
Because meat contains creatine, people who avoid meat may have lower muscle creatine levels. Fortunately, creatine supplementation raises muscle creatine and improves high-intensity performance in plant-based eaters too. And again, the creatine in supplements is synthesised, not taken from meat; plant-based eaters might just want to ensure a capsulated creatine product uses a plant-based capsule.
If you choose to use creatine, a reasonable dose that increases muscle levels of creatine is:
A loading phase of 5 grams of creatine monohydrate, 4 times per day for 5 to 7 days, then a maintenance dose of 3 to 5 grams per day. Note: These doses reliably raise muscle creatine and improve performance in studies.
Or skip loading and take 3 grams per day for 28 days. Note: This slower approach still raises muscle creatine, just later.
Taking more doesn’t necessarily mean a bigger effect, but some studies show that larger athletes may need to ingest up to 5 to 10 grams per day to maintain creatine stores.
When supplementation is stopped, muscle creatine levels usually return to baseline levels in around 4 to 6 weeks.
Can creatine enhance athletic recovery and performance?
Taking a daily creatine supplement alongside regular training is likely to improve performance during maximal strength and reps-to-failure tasks, and during high-intensity/maximal speed-based efforts lasting up to about 30 seconds.
The effect sizeAn effect size is a standardized measure of the magnitude of an effect of an intervention. Unlike p-values, effect sizes show how large the effect is and indicate how meaningful it might be. Common effect size measures include standardised mean difference (SMD), Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients. is medium to large.
The effect appears to be similar between trained athletes and untrained folks.
The effect appears to be larger in males; however, this is probably due to a lack of widespread research in females rather than a lack of a biological effect. Further high-quality creatine research in females is needed!
Meanwhile, supplementation with creatine is unlikely to improve endurance performance — it may even blunt training-induced gains in V̇O2max.
These conclusions are based on a moderate quality of evidenceA moderate quality of evidence means that, in general, studies in this field have some limitations. This could be due to somewhat inconsistent effects between studies, a moderate range of effect sizes between studies, and/or a moderate risk of bias (caused by a small to medium number of studies, small to medium numbers of participants, partially described randomization processes, some missing data, some inappropriate methods/statistics). When the quality of evidence is moderate, there is some doubt and only moderate confidence in the overall effect of an intervention, and future studies could change overall conclusions. The best way to improve the quality of evidence is for scientists to conduct large, well-controlled, high-quality randomized controlled trials.: there’s a large number of reasonably well-designed yet small studies and the effects are fairly consistent between studies (low to moderate heterogeneity/variability)Heterogeneity shows how much the results in different studies in a meta-analysis vary from each other. It is measured as the percentage of variation (the I2 value). A rule of thumb: if I2 is roughly 25%, that indicates low heterogeneity (good), 50% is moderate, and 75% indicates high heterogeneity (bad). High heterogeneity means there’s more variability in effects between studies and, therefore, a less precise overall effect estimate.. So, there’s a moderate level of confidence that the overall effect sizes reported in meta-analysesA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment. reflect the true effect of creatine.
To minimise the risk of consuming a supplement that contains prohibited substances, only choose products that have been independently tested (e.g., Informed Sport). And, remember: Supplements do not make athletes and do not replace training; they're just the icing on a very well-baked cake. Before reaching for pills and potions, optimise your training load and dial in your sleep, nutrition, and rest.
How to use this: If your goal is sprint speed, repeated surges, or strength, consider creatine monohydrate. Either load with 5 grams, 4 times per day for 5 to 7 days, then take 3 to 5 grams daily; or skip loading and take 3 grams daily for 28 days. Be consistent, watch how your gut feels if you also use caffeine, and if you stop, expect muscle creatine levels to drift back to baseline over about 4 to 6 weeks.
The information I provide is not medical advice. Creatine can have side effects and might interact with other drugs, nutrients, and medical conditions (see here). If you are unsure, always consult your doctor to ensure that a specific supplement is safe for you to use.
Full list of meta-analyses examining creatine for performance.
Here are the meta-analyses I've summarised above:
The Effects of Creatine Supplementation on Upper- and Lower-Body Strength and Power: A Systematic Review and Meta-Analysis. Kazeminasab et al. (2025) Nutrients.
Does Creatine Supplementation Enhance Performance in Active Females? A Systematic Review. Tam et al. (2025) Nutrients.
The Effect of Creatine Supplementation on Resistance Training-Based Changes to Body Composition: A Systematic Review and Meta-analysis. Desai et al. (2024) J Strength Cond Res.
Creatine supplementation protocols with or without training interventions on body composition: a GRADE-assessed systematic review and dose-response meta-analysis. Pashayee-Khamene et al. (2024) J Int Soc Sports Nutr.
The Effects of Creatine Supplementation Combined with Resistance Training on Regional Measures of Muscle Hypertrophy: A Systematic Review with Meta-Analysis. Ryan Burke, Alec Piñero, Max Coleman, Adam Mohan, Max Sapuppo, Francesca Augustin, Alan A Aragon, Darren G Candow, Scott C Forbes, Paul Swinton, Brad J Schoenfeld. Nutrients (2023)
Effects of Creatine Monohydrate on Endurance Performance in a Trained Population: A Systematic Review and Meta-analysis. Julen Fernández-Landa, Asier Santibañez-Gutierrez, Nikola Todorovic, Valdemar Stajer, Sergej M Ostojic. Sports Med (2023)
Effectiveness of Creatine in Metabolic Performance: A Systematic Review and Meta-Analysis. Arturo P Jaramillo, Luisa Jaramillo, Javier Castells, Andres Beltran, Neyla Garzon Mora, Sol Torres, Gabriela Carolina Barberan Parraga, Maria P Vallejo, Yurianna Santos. Cureus (2023)
Short-Term Creatine Supplementation and Repeated Sprint Ability-A Systematic Review and Meta-Analysis. Mark Glaister, Lauren Rhodes. Int J Sport Nutr Exerc Metab (2022)
Efficacy of Alternative Forms of Creatine Supplementation on Improving Performance and Body Composition in Healthy Subjects: A Systematic Review. Carly Fazio, Craig L Elder, Margaret M Harris. J Strength Cond Res (2022)
The Paradoxical Effect of Creatine Monohydrate on Muscle Damage Markers: A Systematic Review and Meta-Analysis. Kenji Doma, Akhilesh Kumar Ramachandran, Daniel Boullosa & Jonathan Connor. Sports Med (2022)
Interaction Between Caffeine and Creatine When Used as Concurrent Ergogenic Supplements: A Systematic Review. Sara Elosegui, Jaime López-Seoane, María Martínez-Ferrán, Helios Pareja-Galeano. Int J Sport Nutr Exerc Metab (2022)
Effects of creatine and caffeine ingestion in combination on exercise performance: A systematic review. Alisson H Marinho, Jaqueline S Gonçalves, Palloma K Araújo, Adriano E Lima-Silva, Thays Ataide-Silva, Gustavo G de Araujo. Crit Rev Food Sci Nutr (2021)
Creatine supplementation and VO2 max: a systematic review and meta-analysis. Damien Gras, Charlotte Lanhers, Reza Bagheri, Fred Dutheil. Crit Rev Food Sci Nutr (2021)
The Effect of Creatine Supplementation on Markers of Exercise-Induced Muscle Damage: A Systematic Review and Meta-Analysis of Human Intervention Trials. Northeast B, Clifford T. Int J Sport Nutr Exerc Metab (2021)
Benefits of Creatine Supplementation for Vegetarians Compared to Omnivorous Athletes: A Systematic Review. Kaviani M, Shaw K, Chilibeck PD. Int J Environ Res Public Health (2020)
The Additive Effects of Creatine Supplementation and Exercise Training in an Aging Population: A Systematic Review of Randomized Controlled Trials. Stares A, Bains M. J Geriatr Phys Ther (2020)
Effect of the Combination of Creatine Monohydrate Plus HMB Supplementation on Sports Performance, Body Composition, Markers of Muscle Damage and Hormone Status: A Systematic Review. Fernández-Landa J, Calleja-González J, León-Guereño P, Caballero-García A, Córdova A, Mielgo-Ayuso J. Nutrients (2019)
Effects of Creatine Supplementation on Athletics Performance in Soccer Players: A Systematic Review and Meta-Analysis. Mielgo-Ayuso J, Calleja-Gonzalez J, Marqués-Jiménez D, Caballero-García A, Córdova A, Fernández-Lázaro D. Nutrients (2019)
Effects of creatine supplementation on cognitive function of healthy individuals: A systematic review of randomized controlled trials. Konstantinos I Avgerinos, Nikolaos Spyrou, Konstantinos I Bougioukas, Dimitrios Kapogiannis. Exp Gerontol (2018)
Creatine Supplementation and Upper Limb Strength Performance: A Systematic Review and Meta-Analysis. Lanhers C, Pereira B, Naughton G, Trousselard M, Lesage FX, Dutheil F. Sports Med (2017)
Creatine Supplementation and Lower Limb Strength Performance: A Systematic Review and Meta-Analyses. Lanhers C, Pereira B, Naughton G, Trousselard M, Lesage FX, Dutheil F. Sports Med (2015)
Creatine supplementation and aging musculoskeletal health. Candow DG, Chilibeck PD, Forbes SC. Endocrine (2014)
Creatine supplementation during resistance training in older adults-a meta-analysis. Devries MC, Phillips SM. Med Sci Sports Exerc (2014)
Effect of creatine supplementation on body composition and performance: a meta-analysis. Branch JD. Int J Sport Nutr Exerc Metab (2003)
Does oral creatine supplementation improve strength? A meta-analysis. Dempsey RL, Mazzone MF, Meurer LN. J Fam Pract (2002)
Creatine supplementation as an ergogenic aid for sports performance in highly trained athletes: a critical review. Mujika I, Padilla S. Int J Sports Med (1997)
Consult WADA’s prohibited list.
Cross-check your meds against the Global DRO drug reference list.
Only choose supplements that have been independently tested by Informed Sport or LabDoor. You are the only person responsible for what goes in your body. Ignorance is not an excuse! Stay educated. Be informed.
Nail your daily nutrition habits first, layer specific sports nutrition on top of that, and then start to consider supplements.
The information I provide is not medical advice. Supplements can have side effects and might interact with other drugs, nutrients, and medical conditions. If you are unsure, always consult your doctor to ensure a specific supplement is safe for you to use.
What is nitrate?
Nitrate (NO3-) is a common ion found in high amounts in leafy greens like spinach and in beetroot — the poster child of nitrate talk. After you eat nitrate, your body converts it to nitrite (NO2-), which then helps make nitric oxide (NO). Nitric oxide is a short-lived signaling molecule that widens blood vessels and supports how your cells make energy. However, it has a very short half-life in the body — when nitric oxide is produced, it acts rapidly and is used very quickly.
But, us humans lack the right machinery to reduce nitrate to nitrite and rely on bacteria in our mouth that use an enzyme called nitrate reductase to donate an electron and a proton to do the job:
NO3- + e- + H+ → NO2- + H2O
Nitrate + an Electron + a Proton → Nitrite + Water
Because of that, using a strong alcohol-based mouthwash can disrupt this bacteria-powered pathway — fewer mouth bugs, less nitrite, and less nitric oxide after a nitrate-rich meal (see here & here). Oh NO.
Your body can also make nitric oxide from the amino acid L-arginine using nitric oxide synthase enzymes. Dietary nitrate is simply a second route to the same end product. Since nitric oxide influences blood flow and mitochondrial function, you can see why nitrate or beetroot keeps popping up in sports performance chats. But nitrate’s also a classic PubMed rabbit hole where you can cherry-pick a paper to “prove” either side, so...
What is the scientific evidence on nitrate’s/beetroot’s impact on athletic performance?
Nitrate and beetroot juice are generally safe, but some people get stomach issues. Beetroot can also turn urine red or purple — called beeturia — which is harmless but mildly alarming the first time (see here).
Effects on Strength and power:
A single pre-exercise dose of beetroot juice can increase maximal sprint power and maximal force during all-out contractions (small effect sizeAn effect size is a quantitative measure of the magnitude of a relationship or difference between groups in a study. Unlike p-values, effect sizes show how large or meaningful that effect is. Common effect size measures include Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients.). But, taking it for several days may shrink that effect to basically nothing.
A single dose can also increase muscular endurance in isolated muscle tests (isokinetic contractions) taken to failure (small effect).
These short-term power and endurance benefits may carry over to weightlifting performance (see here), but only a few studies have tested that so far.
Effects on Endurance:
Short-term nitrate use can lower oxygen cost during exercise without changing your average power output. That suggests a small bump in exercise economyThe rate of energy expenditure (measured in kiloJoules [KJ], kilocalories [kcal] or oxygen consumption [V̇O2]) per kilogram body mass (kg) per unit of distance i.e. per 1 kilometer traveled. A runner with a lower energy cost per kilometer has a higher economy than a runner with a higher energy cost. or efficiency. Promising — but keep reading.
When all endurance tests are pooled, the average effect on performance is tiny and the results vary a lot across studies. If we split by test type, nitrate tends to help time-to-exhaustion tasks (exercise capacity at fixed intensity until fatigue) a little, but it doesn’t move the needle in time-trials (time to complete a distance). It also doesn’t seem to help repeated high-intensity efforts during longer endurance sessions or in high-intensity interval or sprint-interval formats.
Studies using nitrate-rich foods like beetroot, red spinach, Swiss chard, or rhubarb report similar patterns — no clear effect on time trials or time-to-exhaustion when dosed once or over the longer term.
Bottom line so far: nitrate can improve running economy and endurance capacity (exercise until you can’t) at lower intensities, but it does not reliably improve time-trial results (go this distance as fast as possible).
All that said, are some important nuances:
Most studies test people when they’re fresh. We don’t know if the same effects hold when you’re already fatigued — for example, after a hard session, then testing again.
The best dose, how many days to take it, and the best timing before exercise aren’t nailed down yet — more good studies needed.
Taking nitrate regularly during a training block doesn’t seem to improve long-term training outcomes compared to training alone (see Hogwood et al. 2023). That said, current studies are small and inconsistent, so confidence is limited.
Meta-analysesA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment.
show that training status matters (here, here, and here). The most reliable benefits show up in recreational athletes. In highly trained folks (especially with V̇O2max around 65 mL/kg/min or higher), the performance boost is mostly absent. The good news: nitrate doesn’t seem to make performance worse.
Females are underrepresented in this research area. A meta-analysis of 9 randomised controlled trialsThe “gold standard” approach for determining whether a treatment has a causal effect on an outcome of interest. In such a study, a sample of people representing the population of interest is randomised to receive the treatment or a no-treatment placebo (control), and the outcome of interest is measured before and after exposure to the treatment and control. in females (Meng et al.) reported a benefit for peak power but not for muscle strength or sprint performance. More trials in females are needed before we can be confident.
Across systematic reviewsA systematic review answers a specific research question by systematically collating all known experimental evidence, which is collected according to pre-specified eligibility criteria. A systematic review helps inform decisions, guidelines, and policy. and meta-analyses, exercise tests, doses, product types, dosing strategies, and durations vary a lot. Reporting quality also varies, which raises the risk of biasRisk of bias in a meta-analysis refers to the potential for systematic errors in the studies included in the analysis. Such errors can lead to misleading/invalid results and unreliable conclusions. This can arise because of issues with the way participants are selected (randomisation), how data is collected and analysed, and how the results are reported.. So, any concrete conclusion needs a pinch of caution.
If you choose to use nitrate/beetroot, a reasonable dose is:
300 to 600 milligrams taken about 2 to 3 hours before exercise. Note: this reflects doses commonly used in research.
You can get that from sodium nitrate, beetroot extract, or beetroot juice.
Taking more doesn’t necessarily mean a bigger effect. Taking more can also increase gastrointestinal issues.
Can nitrate or beetroot enhance athletic recovery and performance?
Taking a nitrate or beetroot supplement before exercise is likely to improve performance during muscular endurance, power, and speed-based events in trained athletes and untrained folks.
The effect sizeAn effect size is a standardized measure of the magnitude of an effect of an intervention. Unlike p-values, effect sizes show how large the effect is and indicate how meaningful it might be. Common effect size measures include standardised mean difference (SMD), Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients. is small.
Taking a nitrate or beetroot supplement before exercise is also likely to improve endurance exercise capacity (time-to-exhaustion) with a small effect size, but is unlikely to improve endurance time trial performance. Importantly, the benefit to exercise capacity is typically only evident in recreational level athletes, and the endurance-enhancing effect appears to be blunted in highly-trained endurance athletes.
Effects appear to be similar between males and females. That said, one meta-analysis found benefits in females on peak power, but not muscle strength or sprint performance. However, further research is needed in females because they are underrepresented among studies in this field.
Keep in mind: because there is moderate heterogeneityHeterogeneity shows how much the results in different studies in a meta-analysis vary from each other. It is measured as the percentage of variation (the I2 value). A rule of thumb: if I2 is roughly 25%, that indicates low heterogeneity (good), 50% is moderate, and 75% indicates high heterogeneity (bad). High heterogeneity means there’s more variability in effects between studies and, therefore, a less precise overall effect estimate. (variability) in effects between studies, moderate risk of biasRisk of bias in a meta-analysis refers to the potential for systematic errors in the studies included in the analysis. Such errors can lead to misleading/invalid results, and unreliable conclusions. ratings, and evidence for publication biasPublication bias in meta-analysis occurs when studies with significant results are more likely to be published than those with non-significant findings, leading to distorted conclusions. This bias can inflate effect sizes and misrepresent the true effectiveness of interventions, making it crucial to identify and correct for it in research., additional high-quality randomised controlled trialsThe “gold standard” approach for determining whether a treatment has a causal effect on an outcome of interest. In such a study, a sample of people representing the population of interest is randomised to receive the treatment or a no-treatment placebo (control), and the outcome of interest is measured before and after exposure to the treatment and control. are needed to increase the certaintyCertainty of evidence tells us how confident we are that the results reflect the true effect. It’s based on factors like study design, risk of bias, consistency, directness, and precision. High certainty means strong, consistent research. Low certainty means more doubt and less confidence, and that new studies could easily change the conclusions. (confidence) in the overall effect sizes reported in meta-analysesA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment..
The nice part: nitrate/beetroot doesn't appear to hurt recovery or performance. So, if you like it and believe it works for you, give it a whirl. But, remember that time and money spent trying to improve your performance with something that has no obvious benefit might be better spent optimising your training load, sleep habits, and dietary/nutritional choices.
To minimise the risk of consuming a supplement that contains prohibited substances, only choose products that have been independently tested (e.g., Informed Sport). And, remember: Supplements do not make athletes and do not replace training; they're just the icing on a very well-baked cake. Before reaching for pills and potions, optimise your training load and dial in your sleep, nutrition, and rest.
How to use this: If you want to experiment, start with 300 to 600 milligrams of nitrate from sodium nitrate, beetroot extract, or beetroot juice taken 2 to 3 hours before key sessions or races. Try it first in training to check your gut, skip strong antiseptic mouthwash on those days, and don’t expect miracles — aim for small wins.
The information I provide is not medical advice. Supplements can have side effects and might interact with other drugs, nutrients, and medical conditions. If you are unsure, always consult your doctor to ensure a specific supplement is safe for you to use.
Full list of meta-analyses examining nitrate and beetroot for performance.
Here are the meta-analyses I've summarised above:
Dietary Nitrate Supplementation and Exercise Performance: An Umbrella Review of 20 Published Systematic Reviews with Meta-analyses. Poon et al. (2025) Sports Med.
Does Nitrate Supplementation Improve Muscle Strength, Power, and Sprint Performance in Females? A Systematic Review and Meta-Analysis. Meng et al. (2025) Life (Basel).
Effects of dietary inorganic nitrate on blood pressure during and post exercise: A systematic review and meta-analysis of randomized placebo-controlled trials. Benjamim et al. (2024) Free Radic Biol Med
Does Beetroot Supplementation Improve Performance in Combat Sports Athletes? A Systematic Review of Randomized Controlled Trials. Delleli et al. (2023) Nutrients
Limited Effects of Inorganic Nitrate Supplementation on Exercise Training Responses: A Systematic Review and Meta-analysis. Hogwood et al. (2023) Sports Med Open
Effects of Dietary Nitrate Supplementation on Back Squat and Bench Press Performance: A Systematic Review and Meta-Analysis. Tan et al. (2023) Nutrients
Effects of Beetroot-Based Supplements on Muscular Endurance and Strength in Healthy Male Individuals: A Systematic Review and Meta-Analysis. Evangelista et al. (2023) JANA
Effects of Dietary Nitrate Supplementation on Performance during Single and Repeated Bouts of Short-Duration High-Intensity Exercise: A Systematic Review and Meta-Analysis of Randomised Controlled Trials. Alsharif et al. (2023) Antioxidants
Factors that Moderate the Effect of Nitrate Ingestion on Exercise Performance in Adults: A Systematic Review with Meta-Analyses and Meta-Regressions. Silva et al. (2022) Adv Nutr
Dietary Inorganic Nitrate as an Ergogenic Aid: An Expert Consensus Derived via the Modified Delphi Technique. Shannon et al. (2022) Sports Med The Effect of Dietary Nitrate on the Contractile Properties of Human Skeletal Muscle: A Systematic Review and Meta-Analysis. Ozcan Esen, Nick Dobbin, Michael J Callaghan. J Am Nutr Assoc (2022)
The Effects of Dietary Nitrate Supplementation on Explosive Exercise Performance: A Systematic Review. Rachel Tan,Leire Cano, Ángel Lago-Rodríguez and Raúl Domínguez. Int J Environ Res Public Health (2022)
The Effect of Beetroot Ingestion on High-Intensity Interval Training: A Systematic Review and Meta-Analysis. Tak Hiong Wong, Alexiaa Sim, Stephen F Burns. Nutrients (2021)
Effect of food sources of nitrate, polyphenols, L-arginine and L-citrulline on endurance exercise performance: a systematic review and meta-analysis of randomised controlled trials. Noah M. A. d’Unienville, Henry T. Blake, Alison M. Coates, Alison M. Hill, Maximillian J. Nelson & Jonathan D. Buckley. J Int Soc Sports Nutr (2021)
Effect of dietary nitrate on human muscle power: a systematic review and individual participant data meta-analysis. Coggan AR, Baranauskas MN, Hinrichs RJ, Liu Z, Carter SJ. J Int Soc Sports Nutr (2021)
Effects of Beetroot Supplementation on Recovery After Exercise-Induced Muscle Damage: A Systematic Review. Rojano-Ortega D, Peña Amaro J, Berral-Aguilar AJ, Berral-de la Rosa FJ. Sports Health (2021)
The effects of dietary nitrate supplementation on endurance exercise performance and cardiorespiratory measures in healthy adults: a systematic review and meta-analysis. Gao C, Gupta S, Adli T, Hou W, Coolsaet R, Hayes A, Kim K, Pandey A, Gordon J, Chahil G, Belley-Cote EP, Whitlock RP. J Int Soc Sports Nutr (2021)
The Effect of Nitrate-Rich Beetroot Juice on Markers of Exercise-Induced Muscle Damage: A Systematic Review and Meta-Analysis of Human Intervention Trials. Jones L, Bailey SJ, Rowland SN, Alsharif N, Shannon OM, Clifford T. < J Diet Suppl (2021)
Effect of dietary nitrate ingestion on muscular performance: a systematic review and meta-analysis of randomized controlled trials. Alvares TS, Oliveira GV, Volino-Souza M, Conte-Junior CA, Murias JM. Crit Rev Food Sci Nutr (2021)
Ergogenic potential of foods for performance and recovery: a new alternative in sports supplementation? A systematic review. Costa MS, Toscano LT, Toscano LLT, Luna VR, Torres RA, Silva JA, Silva AS. Crit Rev Food Sci Nutr (2020)
The Effect of Dietary Nitrate Supplementation on Isokinetic Torque in Adults: A Systematic Review and Meta-Analysis.. Lago-Rodríguez Á, Domínguez R, Ramos-Álvarez JJ, Tobal FM, Jodra P, Tan R, Bailey SJ. Nutrients (2020)
Ergogenic Effect of Nitrate Supplementation: A Systematic Review and Meta-analysis. Senefeld JW, Wiggins CC, Regimbal RJ, Dominelli PB, Baker SE, Joyner MJ. Med Sci Sports Exerc (2020)
Nutritional Ergogenic Aids in Racquet Sports: A Systematic Review. Vicente-Salar N, Santos-Sánchez G, Roche E. Nutrients (2020)
Effects of Dietary Nitrates on Time Trial Performance in Athletes with Different Training Status: Systematic Review. Hlinský T, Kumstát M, Vajda P. Nutrients (2020)
Effects of diet interventions, dietary supplements, and performance-enhancing substances on the performance of CrossFit-trained individuals: A systematic review of clinical studies. Dos Santos Quaresma MVL, Guazzelli Marques C, Nakamoto FP. Nutrition (2021)
Effects of Dietary Nitrate Supplementation on Weightlifting Exercise Performance in Healthy Adults: A Systematic Review. San Juan AF, Dominguez R, Lago-Rodríguez Á, Montoya JJ, Tan R, Bailey SJ. Nutriients (2020)
Effectiveness of beetroot juice derived nitrates supplementation on fatigue resistance during repeated-sprints: a systematic review. Rojas-Valverde D, Montoya-Rodríguez J, Azofeifa-Mora C, Sanchez-Urena B. Crit Rev Food Sci Nutr (2020)
Influence of Nitrate Supplementation on Endurance Cyclic Sports Performance: A Systematic Review. Lorenzo Calvo J, Alorda-Capo F, Pareja-Galeano H, Jiménez SL. Nutrients (2020)
Nutritional Strategies to Optimize Performance and Recovery in Rowing Athletes. Kim J, Kim EK. Nutrients (2020)
The Effect of Nitrate Supplementation on Exercise Tolerance and Performance: A Systematic Review and Meta-Analysis. Van De Walle GP, Vukovich MD. J Strength Cond Res (2018)
Nitrate supplementation improves physical performance specifically in non-athletes during prolonged open-ended tests: a systematic review and meta-analysis. Campos HO, Drummond LR, Rodrigues QT, Machado FSM, Pires W, Wanner SP, Coimbra CC. Br J Nutr (2018)
Performance and Health Benefits of Dietary Nitrate Supplementation in Older Adults: A Systematic Review. Stanaway L, Rutherfurd-Markwick K, Page R, Ali A. Nutrients (2017)
The Effect of Dietary Nitrate Supplementation on Endurance Exercise Performance in Healthy Adults: A Systematic Review and Meta-Analysis. McMahon NF, Leveritt MD, Pavey TG. Sports Med (2017)
Effects of Beetroot Juice Supplementation on Cardiorespiratory Endurance in Athletes. A Systematic Review. Domínguez R, Cuenca E, Maté-Muñoz JL, García-Fernández P, Serra-Paya N, Estevan MC, Herreros PV, Garnacho-Castaño MV. Nutrients (2017)
The effect of nitrate supplementation on exercise performance in healthy individuals: a systematic review and meta-analysis. Hoon MW, Johnson NA, Chapman PG, Burke LM. Int J Sport Nutr Exerc Metab (2013)
Consult WADA’s prohibited list.
Cross-check your meds against the Global DRO drug reference list.
Only choose supplements that have been independently tested by Informed Sport or LabDoor. You are the only person responsible for what goes in your body. Ignorance is not an excuse! Stay educated. Be informed.
Nail your daily nutrition habits first, layer specific sports nutrition on top of that, and then start to consider supplements.
The information I provide is not medical advice. Citrulline can have side effects and might interact with other drugs, nutrients, and medical conditions (see here). If you are unsure, always consult your doctor to ensure that a specific supplement is safe for you to use.
What is citrulline?
Citrulline is a “nonessential” amino acid, which means your body can make it. It isn’t used to build proteins, but it plays a role in the urea cycle and is made when your body produces nitric oxide (NO). In the urea cycle, your liver’s mitochondria turn ammonia (a by-product of hard exercise) into urea so you can excrete it. For a clear primer on the urea cycle, see this overview and the reaction map here.
2 L-arginine + 3 NADPH + 3 H+ + 4 O2 ⇌ 2 L-citrulline + 2 nitric oxide + 4 H2O + 3 NADP+
You can raise blood citrulline by eating watermelon or by taking supplements like L-citrulline or citrulline malate. Malate is part of the tricarboxylic acid (TCA) cycle (your mitochondria’s ATP-making engine). Some folks think adding malate boosts energy production, but we don’t have strong proof that malate adds benefits beyond L-citrulline on its own. During exercise, the two main ideas are simple: more NO may briefly increase blood flow to working muscles, and better ammonia clearance might delay fatigue. Do those ideas translate to real-world performance? Let’s see…
What is the scientific evidence on citrulline’s and watermelon’s impact on athletic performance?
L-citrulline is generally safe to consume for short-term use, though some people report mild stomach upset.
For strength-type efforts, meta-analysesA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all studies of that treatment. show a small improvement in repetitions or power after pre-exercise L-citrulline or citrulline malate (Vårvik et al. 2021, Gough et al. 2021).
For endurance outcomes like V̇O2maxV̇O2max is the maximal rate of oxygen consumption your body can achieve during exercise. It is a measure of cardiorespiratory fitness and indicates the size of your engine, i.e., your maximal aerobic power, which contributes to endurance performance., time to exhaustion, or time-trial performance, current meta-analyses do not show meaningful benefits (Harnden et al. 2023).
Watermelon juice and L-citrulline can improve a vascular health marker called flow-mediated dilation in longer-term use, but translation to faster racing is inconsistent (Smeets et al. 2021).
Most studies test people when they’re fresh. We don’t yet know whether citrulline helps when you’re already fatigued late in a session or race.
I bloody love watermelon, and always feel pretty epic riding home from the grocery store with a massive one in my pannier bag. But, I’ve never tried a citrulline supplement or citrulline malate. Folks who have, tell me it has a sour taste, which means it might be your yin to the yang of a sweet sugary drink.
Typical research doses are about 3 grams of L-citrulline or about 8 grams of citrulline malate taken about 60 minutes before exercise. Some studies suggest that daily dosing for more than 7 days might matter more than a single hit, but results are mixed (Vårvik et al. 2021; Gonzalez et al. 2023).
Bottom line on mechanisms: the evidence for better muscle blood flow during exercise is mixed, and the role of added malate is still up in the air (Gough et al.2021; Aguiar et al.2022). Overall, the current body of evidence is small, the acute vs. chronic effects are not well defined, and the varying dose and duration among studies make firm conclusions difficult.
If you choose to use citrulline or watermelon juice, a reasonable dose is:
~3 grams of L-citrulline (or ~8 grams of citrulline malate) about 60 minutes before exercise is a reasonable starting point based on research use.
Daily dosing for more than 7 days might have a bigger effect than a single pre-exercise dose, but that’s not nailed down.
Matching the suggested dose with watermelon would mean roughly 7.5 to 105 KILOGRAMS of watermelon per day depending on variety and water content — not happening for most of us, but(fun to imagine. (Note: the citrulline content of watermelon ranges from 3.9 to 28.5 mg/g dry weight)
Taking more doesn’t necessarily mean a bigger effect.
Can citrulline or watermelon enhance athletic recovery and performance?
Taking citrulline or watermelon juice before a strength session is somewhat likely to improve performance.
The effect sizeAn effect size is a standardized measure of the magnitude of an effect of an intervention. Unlike p-values, effect sizes show how large the effect is and indicate how meaningful it might be. Common effect size measures include standardised mean difference (SMD), Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients. is trivial to small.
Citrulline and watermelon juice are unlikely to improve endurance performance, but there is little research so effects are uncertain.
Due to insufficient research it is unclear how effects compare between trained athletes and untrained folks, and between males and females.
Keep in mind: because of there is only a small number of trials with a small number of participants, and because effects are inconsistent between studies, certaintyCertainty of evidence tells us how confident we are that the results reflect the true effect. It’s based on factors like study design, risk of bias, consistency, directness, and precision. High certainty means strong, consistent research. Low certainty means more doubt and less confidence, and that new studies could easily change the conclusions. (confidence) in the overall effect sizes reported in meta-analysesA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment. is low-to-moderate at best. Therefore, additional high-quality randomised controlled trialsThe “gold standard” approach for determining whether a treatment has a causal effect on an outcome of interest. In such a study, a sample of people representing the population of interest is randomised to receive the treatment or a no-treatment placebo (control), and the outcome of interest is measured before and after exposure to the treatment and control. are needed to increase the confidence in the currently reported effects.
To minimise the risk of consuming a supplement that contains prohibited substances, only choose products that have been independently tested (e.g., Informed Sport). And, remember: Supplements do not make athletes and do not replace training; they're just the icing on a very well-baked cake. Before reaching for pills and potions, optimise your training load and dial in your sleep, nutrition, and rest.
How to use this: If you want to try it, start with 3 grams of L-citrulline or about 8 grams of citrulline malate about 60 minutes before heavy lifting or hard intervals. Log how you feel and what you lift or output. If you notice zero change after 2 to 3 weeks of targeted use, save your cash and move on.
The information I provide is not medical advice. Citrulline can have side effects and might interact with other drugs, nutrients, and medical conditions (see here). If you are unsure, always consult your doctor to ensure that a specific supplement is safe for you to use.
Full list of meta-analyses examining citrulline and watermelon for performance.
Here are the meta-analyses I've summarised above:
Effects of citrulline on endurance performance in young healthy adults: a systematic review and meta-analysis. Harnden et al. (2023) J Int Soc Sports Nutr
Effects of Citrulline Supplementation on Different Aerobic Exercise Outcomes: A Systematic Review and Meta-Analysis. Viribay et al. (2022) Nutrients
Effects of Citrulline Malate Supplementation on Muscle Strength in Resistance-Trained Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Aguiar et al. (2022) J Diet Suppl
Effect of food sources of nitrate, polyphenols, L-arginine and L-citrulline on endurance exercise performance: a systematic review and meta-analysis of randomised controlled trials. Noah M. A. d’Unienville, Henry T. Blake, Alison M. Coates, Alison M. Hill, Maximillian J. Nelson & Jonathan D. Buckley. J Int Soc Sports Nutr (2021)
Acute Effect of Citrulline Malate on Repetition Performance During Strength Training: A Systematic Review and Meta-Analysis. Vårvik FT, Bjørnsen T, Gonzalez AM. Int J Sport Nutr Exerc Metab (2021)
Nutritional Ergogenic Aids in Racquet Sports: A Systematic Review. Vicente-Salar N, Santos-Sánchez G, Roche E. Nutrients (2020)
Effects of Citrulline Supplementation on Exercise Performance in Humans: A Review of the Current Literature. Gonzalez AM, Trexler ET. J Strength Cond Res (2020)
Effect of citrulline on post-exercise rating of perceived exertion, muscle soreness, and blood lactate levels: A systematic review and meta-analysis. Rhim HC, Kim SJ, Park J, Jang KM. J Sport Health Sci (2020)
Effects of Citrulline alone or combined with exercise on muscle mass, muscle strength, and physical performance among older adults: a systematic review. Aubertin-Leheudre M, Buckinx F. Curr Opin Clin Nutr Metab Care (2020)
Acute Effects of Citrulline Supplementation on High-Intensity Strength and Power Performance: A Systematic Review and Meta-Analysis. Trexler ET, Persky AM, Ryan ED, Schwartz TA, Stoner L, Smith-Ryan AE. Sports Med (2019)
Consult WADA’s prohibited list.
Cross-check your meds against the Global DRO drug reference list.
Only choose supplements that have been independently tested by Informed Sport or LabDoor. You are the only person responsible for what goes in your body. Ignorance is not an excuse! Stay educated. Be informed.
Nail your daily nutrition habits first, layer specific sports nutrition on top of that, and then start to consider supplements.
The information I provide is not medical advice. Supplements can have side effects and might interact with other drugs, nutrients, and medical conditions. If you are unsure, always consult your doctor to ensure a specific supplement is safe for you to use.
What are BCAAs and leucine?
Proteins in your body are always turning over — they’re built and broken down on repeat. You need a minimum daily protein intake to keep basic functions running, including maintaining muscle. Exercise speeds up both building and breakdown, and after exercise — especially strength work — there’s an “anabolic” window of opportunity when eating protein supplies amino acids that tip the balance toward building. If you want a deeper dive, see veohtu.com/protein, veohtu.com/postexercisenutrition, and veohtu.com/carbohydrateplusprotein.
The proteins in your body include enzymes, peptide hormones, neurotransmitters, and the structural stuff that literally holds you together. They’re built from amino acids. Some amino acids help build proteins; others also have roles in metabolism, immunity, and the nervous system. Your body can make some amino acids from other compounds, but it can’t make others (or make them fast enough) — those are the “essential” amino acids you must get from food.
Humans need 9 essential amino acids: phenylalanine, threonine, tryptophan, methionine, leucine, isoleucine, valine, lysine, and histidine. Three of them — leucine, isoleucine, and valine — are called branched-chain amino acids (BCAAs). BCAAs are a bit special because they help build proteins and can act directly in the body. For example, leucine can signal muscles to increase protein synthesis after a meal (see a systematic review on this topic here). Getting BCAAs from food is easy. Omnivores get them from animal and plant foods. People who eat plant-based can also meet needs by eating a variety of plants. Read more at veohtu.com/protein.
Because leucine can drive muscle building and BCAAs have direct effects, supplements became popular and great marketing pushed them into the stratosphere. But, popularity isn’t the same thing as proven performance magic. So…
What is the scientific evidence on BCAA’s and leucine’s impact on athletic performance?
BCAAs are generally safe to take.
Supplementing with BCAAs may reduce post-exercise muscle-damage markers (like creatine kinase in blood) and ease delayed-onset muscle soreness (DOMS) for 24 to 48 hours after tough sessions (often strength or plyometric workouts). The effect sizeAn effect size is a quantitative measure of the magnitude of a relationship or difference between groups in a study. Unlike p-values, effect sizes show how large or meaningful that effect is. Common effect size measures include Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients. is usually moderate to large.
BCAA supplements do not speed the recovery of performance after exercise, nor do they directly improve exercise performance.
In older adults (ages 65 and older), especially people with sarcopenia (muscle loss), daily leucine may help maintain muscle mass (see here, here, and here), but the impact on strength and performance is not convincing. Right now, adequate daily protein plus resistance training looks like the best combo to maintain muscle, strength, and function in older age (see here). There isn’t a meta-analysisA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment. of leucine and performance in younger adults.
In general, this research field is small and results are variable. Studies differ in training status, BCAA dose, timing, and how much muscle damage the exercise causes. We need more high-quality randomised controlled trialsThe “gold standard” approach for determining whether a treatment has a causal effect on an outcome of interest. In such a study, a sample of people representing the population of interest is randomised to receive the treatment or a no-treatment placebo (control), and the outcome of interest is measured before and after exposure to the treatment and control..
If you choose to use BCAAs or leucine, a reasonable dose is:
2 to 3 grams per day of leucine, or a BCAA mix that provides about 2 grams per day of leucine, about 1 gram per day of isoleucine, and about 1 gram per day of valine. Note: based on effective doses used in research.
Taking more doesn’t necessarily mean a bigger effect.
And, don’t forget that whole foods can easily meets your needs:
100 grams of roasted chicken provides about 2.6 grams of leucine, about 1.5 grams of isoleucine, and about 1.5 grams of valine, plus about 24 grams of total protein, about 13 grams of fat including 3 grams of polyunsaturates, some sodium and potassium, and a little iron and vitamin A.
100 grams of tofu provides about 1.4 grams of leucine, about 0.8 grams of isoleucine, and about 0.9 grams of valine, plus about 10 grams of total protein, about 5 grams of fat (mostly unsaturated), and some sodium, potassium, calcium, and iron.
Can BCAAs or leucine enhance athletic recovery and performance?
Supplementation with BCAAs is likely to improve recovery from exercise.
The effect sizeAn effect size is a standardized measure of the magnitude of an effect of an intervention. Unlike p-values, effect sizes show how large the effect is and indicate how meaningful it might be. Common effect size measures include standardised mean difference (SMD), Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients. is medium to large.
The effect appears to be similar between trained athletes and untrained folks, and between males and females.
However, taking a daily dose of BCAAs or leucine or taking a single-dose before/during/after exercise is very unlikely to improve performance.
Keep in mind: because there is moderate heterogeneityHeterogeneity shows how much the results in different studies in a meta-analysis vary from each other. It is measured as the percentage of variation (the I2 value). A rule of thumb: if I2 is roughly 25%, that indicates low heterogeneity (good), 50% is moderate, and 75% indicates high heterogeneity (bad). High heterogeneity means there’s more variability in effects between studies and, therefore, a less precise overall effect estimate. (variability) in effects between studies, mixed risk of biasRisk of bias in a meta-analysis refers to the potential for systematic errors in the studies included in the analysis. Such errors can lead to misleading/invalid results, and unreliable conclusions. ratings, and some (but not all) meta-analyses find evidence for publication biasPublication bias in meta-analysis occurs when studies with significant results are more likely to be published than those with non-significant findings, leading to distorted conclusions. This bias can inflate effect sizes and misrepresent the true effectiveness of interventions, making it crucial to identify and correct for it in research.. So, the overall certainty of evidenceCertainty of evidence tells us how confident we are that the results reflect the true effect. It’s based on factors like study design, risk of bias, consistency, directness, and precision. Low certainty means more doubt and less confidence, and that future studies could easily change the conclusions. High certainty means that the current evidence is so strong and consistent that future studies are unlikely to change conclusions. (confidence) is low-to-moderateA moderate quality of evidence means that, in general, studies in this field have some limitations. This could be due to somewhat inconsistent effects between studies, a moderate range of effect sizes between studies, and/or a moderate risk of bias (caused by a small to medium number of studies, small to medium numbers of participants, poorly described randomization processes, some missing data, some inappropriate methods/statistics). When the quality of evidence is moderate, there is some doubt and only moderate confidence in the overall effect of an intervention, and future studies could change overall conclusions. The best way to improve the quality of evidence is for scientists to conduct large, well-controlled, high-quality randomized controlled trials. for performance and recovery. Therefore, additional high-quality randomised controlled trialsThe “gold standard” approach for determining whether a treatment has a causal effect on an outcome of interest. In such a study, a sample of people representing the population of interest is randomised to receive the treatment or a no-treatment placebo (control), and the outcome of interest is measured before and after exposure to the treatment and control. are needed to increase confidence in the overall effect sizes reported in meta-analysesA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment..
Eating whole foods that contain protein provides us with the entire range of amino acids in adequate amounts. For this reason, when following a healthy eating pattern with an adequate daily protein intake, there is absolutely no rational basis for supplementing with specific amino acids. This is because drinking a BCAA-containing drink or taking a leucine pill doesn’t initiate any magic on top of high-quality protein you have already ingested.
In fact, supplementing with such things while neglecting whole foods may leave you deficient in total protein and lacking in other specific amino acids. So, if you want to “branch” out and get your BCAA fix, go and eat some tasty protein-containing whole food.
The nice part: BCAAs and leucine do not appear to have a detrimental effect on recovery or performance. So, if you like it and believe it works for you, give it a whirl. But, remember that time and money spent trying to improve your performance with something that has no obvious benefit might be better spent optimising your training load, sleep habits, and dietary/nutritional choices.
To minimise the risk of consuming a supplement that contains prohibited substances, only choose products that have been independently tested (e.g., Informed Sport). And, remember: Supplements do not make athletes and do not replace training; they're just the icing on a very well-baked cake. Before reaching for pills and potions, optimise your training load and dial in your sleep, nutrition, and rest.
How to use this: If you’re curious, try BCAAs after your hardest strength or downhill sessions for a few weeks and see if soreness drops — keep the dose in the ranges above, keep your daily protein intake adequate, and don’t expect faster times on race day. Track how you feel, then keep or ditch it.
The information I provide is not medical advice. Supplements can have side effects and might interact with other drugs, nutrients, and medical conditions. If you are unsure, always consult your doctor to ensure a specific supplement is safe for you to use.
Full list of meta-analyses examining BCAAs and leucine for performance.
Here are the meta-analyses I've summarised above:
Attenuating Muscle Damage Biomarkers and Muscle Soreness After an Exercise-Induced Muscle Damage with Branched-Chain Amino Acid (BCAA) Supplementation: A Systematic Review and Meta-analysis with Meta-regression. Salem et al. (2024) Sports Med Open
International Society of Sports Nutrition Position Stand: Effects of essential amino acid supplementation on exercise and performance. Ferrando et al. (2023) J Int Soc Sports Nutr
Association of postprandial postexercise muscle protein synthesis rates with dietary leucine: A systematic review. Wilkinson et al. (2023) Physiol Rep
The use of BCAA to decrease delayed-onset muscle soreness after a single bout of exercise: a systematic review and meta-analysis. Martim Gomes Weber, Silas Seolin Dias, Tarlyson Regioli de Angelis, Eduardo Vignoto Fernandes, Andrea Gomes Bernardes, Vinicius Flavio Milanez, Eduardo Inocente Jussiani, Solange de Paula Ramos. Amino acids (2021)
Intake of branched chain amino acids favors post-exercise muscle recovery and may improve muscle function: optimal dosage regimens and consumption conditions. Alejandra Arroyo-Cerezo, Isabel Cerrillo, Ángeles Ortega, María-Soledad Fernández-Pachón. J Sports Med Phys Fitness (2021)
Does Branched-Chain Amino Acids (BCAAs) Supplementation Attenuate Muscle Damage Markers and Soreness after Resistance Exercise in Trained Males? A Meta-Analysis of Randomized Controlled Trials. Chutimon Khemtong, Chia-Hua Kuo, Chih-Yen Chen, Salvador J Jaime, Giancarlo Condello. Nutrients (2021)
The effect of branched-chain amino acid on muscle damage markers and performance following strenuous exercise: a systematic review and meta-analysis. Kenji Doma, Utkarsh Singh, Daniel Boullosa, Jonathan Douglas Connor. Appl Physiol Nutr Metab (2021)
Nutritional interventions to improve muscle mass, muscle strength, and physical performance in older people: an umbrella review of systematic reviews and meta-analyses. Gielen E, Beckwée D, Delaere A, De Breucker S, Vandewoude M, Bautmans I; Sarcopenia Guidelines Development Group of the Belgian Society of Gerontology and Geriatrics (BSGG). Nutr Rev (2021)
Effect of Branched-Chain Amino Acid Supplementation on Muscle Soreness following Exercise: A Meta-Analysis. Fedewa MV, Spencer SO, Williams TD, Becker ZE, Fuqua CA. Int J Vitam Nutr Res (2019)
Branched-chain amino acid supplementation and exercise-induced muscle damage in exercise recovery: A meta-analysis of randomized clinical trials. Rahimi MH, Shab-Bidar S, Mollahosseini M, Djafarian K. Nutrition (2017)
Effects of branched amino acids in endurance sports: a review. (SPANISH) Salinas-García ME, Martínez-Sanz JM, Urdampilleta A, Mielgo-Ayuso J, Norte Navarro A, Ortiz-Moncada R. Nutr Hosp (2014)
Consult WADA’s prohibited list.
Cross-check your meds against the Global DRO drug reference list.
Only choose supplements that have been independently tested by Informed Sport or LabDoor. You are the only person responsible for what goes in your body. Ignorance is not an excuse! Stay educated. Be informed.
Nail your daily nutrition habits first, layer specific sports nutrition on top of that, and then start to consider supplements.
The information I provide is not medical advice. Supplements can have side effects and might interact with other drugs, nutrients, and medical conditions. If you are unsure, always consult your doctor to ensure a specific supplement is safe for you to use.
What is HMB?
β-hydroxy β-methylbutyrate (HMB) is a naturally occurring carboxylic acid that circulates in tiny amounts in your blood. Your body makes it from leucine, an amino acid found in protein-rich foods. You’ll also find trace amounts of HMB in foods like asparagus, avocados, cauliflower, and grapefruit. HMB is present in muscle, can cross the blood–brain barrier, and is cleared in urine.
Researchers have studied HMB for decades. Early work in the 1990s showed that HMB taken during resistance training can affect muscle function, and later studies found that HMB can both stimulate muscle protein synthesis and reduce muscle protein breakdown. Because of that, HMB often appears in high-protein medical foods, such as Ensure, used to help counter muscle loss (cachexia) in people with conditions like cancer and AIDS. But…
What is the scientific evidence on HMB’s impact on athletic performance?
HMB is generally safe to consume for most healthy adults.
Most research has tested HMB during strength training. Far fewer studies look at HMB during aerobic or endurance training.
Daily HMB during regular training might help endurance performance a little, but we need higher-quality trials to be confident.
In athletes, HMB may slightly increase fat-free mass (FFM), a marker of muscle mass (small effect sizeAn effect size is a quantitative measure of the magnitude of a relationship or difference between groups in a study. Unlike p-values, effect sizes show how large or meaningful that effect is. Common effect size measures include Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients.) without changing total body weight or fat mass. This small effect tends to fade when athletes already eat enough protein (at least 1.6 grams per kilogram per day).
In older untrained adults (ages 50 to 80), daily HMB without strength training may increase FFM and strength a little (small effect sizesAn effect size is a quantitative measure of the magnitude of a relationship or difference between groups in a study. Unlike p-values, effect sizes show how large or meaningful that effect is. Common effect size measures include Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients.), but once people start strength training, HMB doesn’t seem to add more on top for body composition, strength, or function comnpared to strength training alone.
In younger adults (ages 18 to 50), HMB during a strength program can increase strength a bit (small effect sizeAn effect size is a quantitative measure of the magnitude of a relationship or difference between groups in a study. Unlike p-values, effect sizes show how large or meaningful that effect is. Common effect size measures include Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients.) — but mainly in previously untrained men. In trained athletes, HMB doesn’t improve strength or performance.
The bottom line: HMB may help recovery by reducing signs of muscle damage, but we still need more high-quality work and a solid meta-analysisA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment.. Evidence for endurance performance is still too thin to be sure.
If you choose to use HMB, a reasonable dose is:
3 grams per day as a single dose, or 1 gram taken 3 times per day. Note: this matches doses used in research.
That’s roughly the HMB you’d get from about 6000 avocados. Please don’t do that. If someone at the gym offers you that many avocados, say “oh no” to avocado.
Taking more doesn’t necessarily mean a bigger effect.
Can HMB enhance athletic recovery and performance?
In older-aged people who DO NOT strength train, daily supplementation with HMB is somewhat likely to increase fat-free mass (a marker of muscle mass). The effect sizeAn effect size is a standardized measure of the magnitude of an effect of an intervention. Unlike p-values, effect sizes show how large the effect is and indicate how meaningful it might be. Common effect size measures include standardised mean difference (SMD), Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients. is small. The effect on strength is less clear, and the effect of HMB is not observed in older-aged people who strength train.
In trained athletes who consume insufficient daily protein, daily supplementation with HMB is also somewhat likely to increase fat-free mass (a marker of muscle mass). The effect sizeAn effect size is a standardized measure of the magnitude of an effect of an intervention. Unlike p-values, effect sizes show how large the effect is and indicate how meaningful it might be. Common effect size measures include standardised mean difference (SMD), Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients. is small.
In young (18 to 50 years old) previous untrained adults, daily supplementation with HMB is likely to increase muscle strength during a strength training intervention. The effect sizeAn effect size is a standardized measure of the magnitude of an effect of an intervention. Unlike p-values, effect sizes show how large the effect is and indicate how meaningful it might be. Common effect size measures include standardised mean difference (SMD), Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients. is small.
In trained athletes, daily supplementation with HMB is unlikely to increase muscle strength.
The effect of HMB on endurance performance is uncertain due to insufficient evidence.
It is also unclear whether the effects described above are similar between males and females, because females are underrepresented among studies in this field.
Keep in mind: there is high heterogeneityHeterogeneity shows how much the results in different studies in a meta-analysis vary from each other. It is measured as the percentage of variation (the I2 value). A rule of thumb: if I2 is roughly 25%, that indicates low heterogeneity (good), 50% is moderate, and 75% indicates high heterogeneity (bad). High heterogeneity means there’s more variability in effects between studies and, therefore, a less precise overall effect estimate. (variability) in effects between studies, and because there is a general low quality of evidenceA low quality of evidence means that, in general, studies in this field have several limitations. This could be due to inconsistency in effects between studies, a large range of effect sizes between studies, and/or a high risk of bias (caused by inappropriate controls, a small number of studies, small numbers of participants, poor/absent randomisation processes, missing data, inappropriate methods/statistics). When the quality of evidence is low, there is more doubt and less confidence in the overall effect of an intervention, and new studies could easily change overall conclusions. The most effective way to enhance the quality of evidence is for scientists to conduct large, well-controlled, high-quality randomised controlled trials.. So, additional high-quality randomised controlled trialsThe “gold standard” approach for determining whether a treatment has a causal effect on an outcome of interest. In such a study, a sample of people representing the population of interest is randomised to receive the treatment or a no-treatment placebo (control), and the outcome of interest is measured before and after exposure to the treatment and control. are needed to increase the certaintyCertainty of evidence tells us how confident we are that the results reflect the true effect. It’s based on factors like study design, risk of bias, consistency, directness, and precision. High certainty means strong, consistent research. Low certainty means more doubt and less confidence, and that new studies could easily change the conclusions. (confidence) in these conclusions.
The nice part: HMB doesn't appear to hurt recovery or performance. So, if you like it and believe it works for you, give it a whirl. But, remember that time and money spent trying to improve your performance with something that has no obvious benefit might be better spent optimising your training load, sleep habits, and dietary/nutritional choices.
To minimise the risk of consuming a supplement that contains prohibited substances, only choose products that have been independently tested (e.g., Informed Sport). And, remember: Supplements do not make athletes and do not replace training; they're just the icing on a very well-baked cake. Before reaching for pills and potions, optimise your training load and dial in your sleep, nutrition, and rest.
How to use this: If you decide to experiment, take 3 grams of HMB daily (either once or split into 3 doses). Give it several weeks while keeping training, sleep, and protein intake consistent. If you don’t notice practical benefits — feeling or performing better — save your money for shoes, coaching, good food, and the occasional phenomenal beerLiquid joy. The thing I drink when I don’t train..
The information I provide is not medical advice. Supplements can have side effects and might interact with other drugs, nutrients, and medical conditions. If you are unsure, always consult your doctor to ensure a specific supplement is safe for you to use.
Full list of meta-analyses examining HMB for performance.
Here are the meta-analyses I've summarised above:
Effects of oral supplementation of β-hydroxy-β-methylbutyrate on muscle mass and strength in individuals over the age of 50: a meta-analysis. Li et al. (2025) Front Nutr.
Ergogenic Benefits of β-Hydroxy-β-Methyl Butyrate (HMB) Supplementation on Body Composition and Muscle Strength: An Umbrella Review of Meta-Analyses. Bideshki et al. (2025) J Cachexia Sarcopenia Muscle.
Effects of HMB on Endurance Performance in a Healthy Population: A Systematic Review and Meta-Analysis. Fernández-Landa et al. (2024) J Strength Cond Res
An umbrella review of systematic reviews of β‐hydroxy‐β‐methyl butyrate supplementation in ageing and clinical practice. Stuart M. Phillips, Kyle J. Lau, Alysha C. D'Souza, Everson A. Nunes. J Cachexia Sarcopenia Muscle (2022)
Does HMB Enhance Body Composition in Athletes? A Systematic Review and Meta-analysis. Brett M Holland, Brandon M Roberts, James W Krieger, Brad J Schoenfeld. J Strength Cond Res (2022)
Effects of oral administration of β-hydroxy β-methylbutyrate on lean body mass in older adults: a systematic review and meta-analysis. Lin Z, Zhao Y, Chen Q. Eur Geriatr Med (2021)
Nutritional Strategies to Optimize Performance and Recovery in Rowing Athletes. Kim J, Kim EK. Nutrients (2020)
Supplementation with the Leucine Metabolite β-hydroxy-β-methylbutyrate (HMB) does not Improve Resistance Exercise-Induced Changes in Body Composition or Strength in Young Subjects: A Systematic Review and Meta-Analysis.
Jakubowski JS, Nunes EA, Teixeira FJ, Vescio V, Morton RW, Banfield L, Phillips SM. Nutrients (2020)
Does HMB Enhance Body Composition in Athletes? A Systematic Review and Meta-analysis. Holland BM, Roberts BM, Krieger JW, Schoenfeld BJ. J Strength Cond Res (2019)
Health Benefits of β-Hydroxy-β-Methylbutyrate (HMB) Supplementation in Addition to Physical Exercise in Older Adults: A Systematic Review with Meta-Analysis. Courel-Ibáñez J, Vetrovsky T, Dadova K, Pallarés JG, Steffl M. Nutrients (2019)
The Effects of Beta-Hydroxy-Beta-Methylbutyrate Supplementation on Recovery Following Exercise-Induced Muscle Damage: A Systematic Review and Meta-Analysis. Rahimi MH, Mohammadi H, Eshaghi H, Askari G, Miraghajani M. J Am Coll Nutr (2018)
Effects of beta-hydroxy-beta-methylbutyrate supplementation on strength and body composition in trained and competitive athletes: A meta-analysis of randomized controlled trials. Sanchez-Martinez J, Santos-Lozano A, Garcia-Hermoso A, Sadarangani KP, Cristi-Montero C. J Sci Med Sport (2018)
β-hydroxy-β-methylbutyrate free acid supplementation may improve recovery and muscle adaptations after resistance training: a systematic review. Silva VR, Belozo FL, Micheletti TO, Conrado M, Stout JR, Pimentel GD, Gonzalez AM. Nutr Res (2017)
Beta-hydroxy-beta-methylbutyrate supplementation in health and disease: a systematic review of randomized trials. Molfino A, Gioia G, Rossi Fanelli F, Muscaritoli M. Amino Acids (2013)
Effects of beta-hydroxy-beta-methylbutyrate supplementation during resistance training on strength, body composition, and muscle damage in trained and untrained young men: a meta-analysis. Rowlands DS, Thomson JS. J Strength Cond Res (2009)
Effect of dietary supplements on lean mass and strength gains with resistance exercise: a meta-analysis. Nissen SL, Sharp RL. J Appl Physiol (2003)
Consult WADA’s prohibited list.
Cross-check your meds against the Global DRO drug reference list.
Only choose supplements that have been independently tested by Informed Sport or LabDoor. You are the only person responsible for what goes in your body. Ignorance is not an excuse! Stay educated. Be informed.
Nail your daily nutrition habits first, layer specific sports nutrition on top of that, and then start to consider supplements.
The information I provide is not medical advice. Supplements can have side effects and might interact with other drugs, nutrients, and medical conditions. If you are unsure, always consult your doctor to ensure a specific supplement is safe for you to use.
What are beta-alanine, carnosine, and anserine?
Some amino acids build proteins; others moonlight. Beta-alanine is an amino acid, but unlike its more famous sibling, L-alanine, it doesn’t get stitched into proteins. Instead, beta-alanine can nudge nerve signaling by acting as a neurotransmitter and binding to GABA and NMDA receptors. Crucially, for athletes, your body also uses beta-alanine plus histidine to make carnosine (β-alanyl-L-histidine), which sits inside muscle and buffers hydrogen ions (H+) when intensity spikes, helping keep pH in check.
β-alanine + histidine + ATP ⇌ carnosine + ADP + Pi
Supplementing with beta-alanine can raise muscle carnosine content (see Rezende et al. 2020), which is why it’s popular in sport. Oral carnosine sounds simpler, but your gut breaks it back down into histidine and beta-alanine. A related compound, anserine (carnosine with a —CH3 group attached to it; made from beta-alanine and 3-methylhistidine), resists breakdown a bit better and, like carnosine, also buffers pH inside muscle. So…
What is the scientific evidence on beta-alanine’s, carnosine’s, and anserine’s impact on athletic performance?
Beta-alanine is generally safe to consume (see here). A common side effect is a short, harmless tingling or prickling called paraesthesia — it fades quickly and not everyone gets it. Many studies don’t fully report side effects, so the true rate isn’t clear.
Performance gains show up most in short, very hard efforts powered mainly by glycolysis (glucose breakdown). That’s your fast war-face zone.
The sweet spot for beta-alanine supplementation is exercise lasting about 30 seconds to 10 minutes (although earlier evidence pointed to roughly 1 to 4 minutes). Below 30 seconds, benefits haven’t been found.
Co-supplementing daily beta-alanine with pre-exercise sodium bicarbonate produced the largest effect sizeAn effect size is a quantitative measure of the magnitude of a relationship or difference between groups in a study. Unlike p-values, effect sizes show how large or meaningful that effect is. Common effect size measures include Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients. when compared with placebo (see here and here).
Why does beta-alanine help? Carnosine buffers H+, but it may also help mop up inorganic phosphate (Pi) that piles up during repeated hard contractions. Together, H+ and Pi can impair force and power more than either alone — a truly annoying tag-team that hovers on the dark side of the force.
Some nerdiness: It is debated whether buffering compounds like beta-alanine are performance enhancing because of their H+ buffering capacity or whether they are performance enhancing because they also buffer the intramuscular phosphate (Pi) that accumulates during high-intensity exercise (which is a series of high force muscle contractions). Some evidence shows that H+ (hydrogen) and Pi (phosphate) ions in combination more strongly impair maximal isometric force and peak power than what either ion exerts individually. Therefore, H+ and Pi accumulation during high-intensity exercise may synergistically and additively reduce muscle function during fatigue.
But, what about carnosine and anserine as alternative supplements to beta-alanine? Well, there is not currently a meta-analysisA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment. on carnosine and anserine supplementation. That said, fun fact: chicken broth is loaded with both carnosine and anserine, and one small study hinted that pre-exercise chicken broth (rich in carnosine and anserine) improved a cycling time trial.
If you choose to use beta-alanine, a reasonable dose is:
about 6 grams per day for roughly 2 to 4 weeks raises muscle carnosine. Note: this is based on effective doses used in research.
Taking more doesn’t necessarily mean a bigger effect.
The chicken broth thing: since there is approximately 1 gram of carnosine in 600 mL of chicken broth, which is broken down to approximately 570 milligrams of beta-alanine, you’d have to drink about 6 litres of chicken broth per day to obtain 6 g/day of beta-alanine. Don’t do that! And, if anyone down your gym tells you to chug chicken broth, they’re probably a cock; send them clucking!
If you stop supplementing, how fast muscle carnosine levels drift back to baseline is unclear — studies don’t agree yet.
Can beta-alanine enhance athletic recovery and performance?
Taking a daily beta-alanine supplement is likely to improve performance during high-intensity short-duration events lasting between 30-seconds and 10-minutes.
The effect sizeAn effect size is a standardized measure of the magnitude of an effect of an intervention. Unlike p-values, effect sizes show how large the effect is and indicate how meaningful it might be. Common effect size measures include standardised mean difference (SMD), Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients. is small.
The effect appears to be similar between trained athletes and untrained folks, and between males and females; however, further research is needed in females because they are underrepresented among studies in this field.
These conclusions are based on a moderate quality of evidenceA high quality of evidence means that, in general, there is a small range of effect sizes between studies, effects are consistent, and there is a low risk of bias (due to a large number of studies, large numbers of participants, good study designs, appropriate methods, etc). When the quality of evidence is high, there is a high level of confidence that the overall effect size reflects the true effect.: effects are reasonably consistent between studies, but additional high-quality randomised controlled trialsThe “gold standard” approach for determining whether a treatment has a causal effect on an outcome of interest. In such a study, a sample of people representing the population of interest is randomised to receive the treatment or a no-treatment placebo (control), and the outcome of interest is measured before and after exposure to the treatment and control. are needed to increase overall quality of evidence. Consequently, there’s a moderate level of confidence that the overall effect sizes reported in meta-analysesA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment. reflect the true effect of beta-alanine.
Due to insufficient evidence, the effect of carnosine or anserine on performance is currently unclear. This may change when a meta-analysis becomes available.
To minimise the risk of consuming a supplement that contains prohibited substances, only choose products that have been independently tested (e.g., Informed Sport). And, remember: Supplements do not make athletes and do not replace training; they're just the icing on a very well-baked cake. Before reaching for pills and potions, optimise your training load and dial in your sleep, nutrition, and rest.
How to use this: If your target events include hard efforts of roughly 30 seconds to 10 minutes, consider a daily beta-alanine phase: about 6 grams per day for around 2 to 4 weeks. You don’t need megadoses. For very short efforts (under 30 seconds) or steady long races, don’t expect much. Some athletes pair daily beta-alanine with pre-race sodium bicarbonate for extra punch on short, intense efforts; if you try that combo, test it well before race day.
The information I provide is not medical advice. Supplements can have side effects and might interact with other drugs, nutrients, and medical conditions. If you are unsure, always consult your doctor to ensure a specific supplement is safe for you to use.
Full list of meta-analyses examining beta-alanine, carnosine, and anserine for performance.
Here are the meta-analyses I've summarised above:
Dosing strategies for β-alanine supplementation in strength and power performance: a systematic review. Ong et al. (2025) J Int Soc Sports Nutr.
Effect of Beta-Alanine Supplementation on Maximal Intensity Exercise in Trained Young Male Individuals: A Systematic Review and Meta-Analysis. Georgiou et al. (2024) Int J Sport Nutr Exerc Metab.
β-Alanine Supplementation in Combat Sports: Evaluation of Sports Performance, Perception, and Anthropometric Parameters and Biochemical Markers-A Systematic Review of Clinical Trials. Fernández-Lázaro et al. (2023) Nutrients
Effects of beta-alanine supplementation on body composition: a GRADE-assessed systematic review and meta-analysis. Damoon Ashtary-Larky, Reza Bagheri, Matin Ghanavati, Omid Asbaghi, Alexei Wong, Jeffrey R Stout, Katsuhiko Suzuki. J Int Soc Sports Nutr (2022)
Effect of β-alanine and sodium bicarbonate co-supplementation on the body's buffering capacity and sports performance: A systematic review. Laura Gilsanz, Jaime López-Seoane, Sergio L Jiménez, Helios Pareja-Galeano. Crit Rev Food Sci Nutr (2021)
Individual Participant Data Meta-Analysis Provides No Evidence of Intervention Response Variation in Individuals Supplementing With Beta-Alanine. Gabriel Perri Esteves, Paul Swinton, Craig Sale, Ruth M James, Guilherme Giannini Artioli, Hamilton Roschel, Bruno Gualano, Bryan Saunders, Eimear Dolan. Int J Sport Nutr Exerc Metab (2021)
Effects of beta-alanine supplementation on Yo-Yo test performance: A meta-analysis. Jozo Grgic. Clin Nutr ESPEN (2021)
The Muscle Carnosine Response to Beta-Alanine Supplementation: A Systematic Review With Bayesian Individual and Aggregate Data E-Max Model and Meta-Analysis. Rezende et al. (2020) Front Physiol
Effects of Beta-Alanine Supplementation on Physical Performance in Aerobic-Anaerobic Transition Zones: A Systematic Review and Meta-Analysis. Ojeda et al. (2020) Nutrients
Effects of Beta-Alanine Supplementation on Physical Performance in Aerobic–Anaerobic Transition Zones: A Systematic Review and Meta-Analysis. Álvaro Huerta Ojeda, Camila Tapia Cerda, María Fernanda Poblete Salvatierra, Guillermo Barahona-Fuentes, and Carlos Jorquera Aguilera. Nutrients (2020)
Effect of Supplements on Endurance Exercise in the Older Population: Systematic Review. Martínez-Rodríguez A, Cuestas-Calero BJ, Hernández-García M, Martíez-Olcina M, Vicente-Martínez M, Rubio-Arias JÁ. Int J Environ Res Public Health (2020)
Nutritional Strategies to Optimize Performanceand Recovery in Rowing Athletes. Kim J, Kim EK. Nutrients (2020)
The Impact of Preconditioning Strategies Designed to Improve 2000-m Rowing Ergometer Performance in Trained Rowers: A Systematic Review and Meta-Analysis. Turnes T, Cruz RSO, Caputo F, De Aguiar RA. Int J Sports Physiol Perform (2019)
β-alanine supplementation to improve exercise capacity and performance: a systematic review and meta-analysis. Saunders B, Elliott-Sale K, Artioli GG, Swinton PA, Dolan E, Roschel H, Sale C, Gualano B. Br J Sports Med (2017)
Effects of beta-alanine supplementation on performance and muscle fatigue in athletes and non-athletes of different sports: a systematic review. Berti Zanella P, Donner Alves F, Guerini de Souza C. J Sports Med Phys Fitness (2017)
The effects of beta-alanine supplementation on performance: a systematic review of the literature. Quesnele JJ, Laframboise MA, Wong JJ, Kim P, Wells GD. Int J Sport Nutr Exerc Metab (2014)
Effects of β-alanine supplementation on exercise performance: a meta-analysis. Hobson RM, Saunders B, Ball G, Harris RC, Sale C. Amino Acids (2012)
Consult WADA’s prohibited list.
Cross-check your meds against the Global DRO drug reference list.
Only choose supplements that have been independently tested by Informed Sport or LabDoor. You are the only person responsible for what goes in your body. Ignorance is not an excuse! Stay educated. Be informed.
Nail your daily nutrition habits first, layer specific sports nutrition on top of that, and then start to consider supplements.
The information I provide is not medical advice. Sodium bicarbonate (bicarb) can have side effects and might interact with other drugs, nutrients, and medical conditions (see here). If you are unsure, always consult your doctor to ensure that a specific supplement is safe for you to use.
What is sodium bicarbonate?
Sodium bicarbonate (NaHCO3) is a salt made of a sodium ion (Na+) and a bicarbonate ion (HCO3−). You probably know it as baking soda — the white stuff hiding in your cupboard and sneaking into muffins.
In the oven, heat causes sodium bicarbonate (baking soda) to spontaneously react and release carbon dioxide, which helps dough rise:
2 NaHCO3 → Na2CO3 + CO2 + H2O
Note: this reaction does not occur in your body.
In your gut, bicarb acts like an antacid — it neutralizes stomach acid and can ease heartburn and indigestion. When it meets acid (H+ ions, or HCl in the stomach), you get sodium (Na+ or NaCl in the stomach), water, and carbon dioxide::
NaHCO3 + H+ → Na+ + CO2 + H2O
Now you’re probably starting to see how bicarbonate might work in the context of exercise.
So, zooming out: your body runs a built-in bicarbonate buffering system to keep pH in a safe zone. Your stomach, for example, operates optimally at an “acidic” pH, which would destroy the epithelial cell lining of your gastrointestinal system (the gastric mucosa) if the bicarbonate buffering system was not present to protect the cells from stomach acid. Meanwhile, your blood is tightly regulated around a neutral pH. When hard exercise ramps up carbon dioxide and hydrogen ions, the buffering system steps in — it binds H+ ions and helps move CO2 to your lungs so you can puff it out:
CO2 + H2O ⇌ H2CO3 ⇌ HCO3- + H+
Carbon dioxide + Water ⇌ Carbonic acid ⇌ Bicarbonate + Hydrogen ion
Like all buffers, the bicarbonate buffering system in your body consists of a weak acid (carbonic acid, H2CO3) and its conjugate base (bicarbonate, HCO3--) that helps neutralise any excess acid or base that appears.
During very hard, glycolytic efforts — when you’re burning through glucose to make ATP fast — you produce carbon dioxide (CO2) at a high rate and hydrogen ions (H+) can accumulate possibly causing intramuscular acidosis (a drop in pH in muscles), which is one (of many) theorised causes of fatigue. So, adding an external buffer can help your internal buffering system overcome the large disturbance in the force. That’s why athletes have played with bicarb for decades. Fun fact: famous exercise physiologists like David Bruce (D.B.) Dill in the Harvard Fatigue Laboratory were studying the effects of sodium bicarbonate in runners over 100-years ago! But…
What is the scientific evidence on sodium bicarbonate’s impact on athletic performance?
Bicarb is generally safe for healthy people to consume, and it reliably boosts blood bicarbonate, lowers hydrogen ions, and helps steady blood pH during hard work (see Oliveira et al. 2021, Calvo et al. 2021, Siegler et al. 2016, Grgic et al. 2016, Carr et al. 2011, Renfree 2007).
However, some people get stomach issues — bloating, nausea, maybe vomiting — likely from the reaction with stomach acid (see Siegler et al. 2016 and Grgic et al. 2016). Test it in training first, not on race day.
Before exercise, bicarb can improve muscular endurance (reps to failure and time-to-maintain isometric force) in single-joint moves (knee extensions, elbow flexion) and big compound lifts (squat, bench, pull-up) with a small effect sizeAn effect size is a quantitative measure of the magnitude of a relationship or difference between groups in a study. Unlike p-values, effect sizes show how large or meaningful that effect is. Common effect size measures include Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients..
But, it does not improve muscular strength.
For long-duration endurance events, bicarb hasn’t shown clear performance gains (neither in humans nor in horses; yes, “it is time to stop horsing around with baking soda”).
In short, very hard efforts that last roughly 45 seconds to 8 minutes, bicarb may improve performance. But, effect sizesAn effect size is a quantitative measure of the magnitude of a relationship or difference between groups in a study. Unlike p-values, effect sizes show how large or meaningful that effect is. Common effect size measures include Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients. are trivial to small on average, and there’s some uncertainty due to possible publication biasPublication bias in meta-analysis occurs when studies with significant results are more likely to be published than those with non-significant findings, leading to distorted conclusions. This bias can inflate effect sizes and misrepresent the true effectiveness of interventions, making it crucial to identify and correct for it in research. and unclear study quality — more high-quality work is needed.
In very-short duration, 30-second “all-out” Wingate cycling tests (“all-out” cycling for 30 seconds on a cycling ergometer), pre-exercise sodium bicarbonate supplementation does not enhance peak or average power output but might benegfit average power during repeated maximal sprints (small effect sizeAn effect size is a quantitative measure of the magnitude of a relationship or difference between groups in a study. Unlike p-values, effect sizes show how large or meaningful that effect is. Common effect size measures include Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients.).
Most studies test people when they’re fresh. We don’t yet know if the same benefits hold when you’re already fatigued — for example, after a long ride or run and then a finishing effort.
There’is a current sex bias in this field — only 20% of studies include females — but a preliminary meta-analysisA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment. shows that the effects of sodium bicarbonate supplementation are similar between males and females.
It’s unclear if taking bicarb daily beats a single pre-exercise dose. One meta-analysisA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment. (see here) found trivial average benefits from a one-off pre-exercise dose in Wingate tests, but a large effect after daily dosing. However, that conclusion was based on only two studies, so treat it with a pinch of salt bicarb.
Combining daily beta-alanine with pre-exercise bicarb shows the biggest average benefit compared with placebo in some meta-analyses (see here and here). That combo may suit folks doing short, hard intervals or events.
If you choose to use bicarbonate, a reasonable dose is:
0.2 to 0.3 grams per kilogram of body weight, taken 1 to 3 hours before high-intensity exercise. Note: based on effective doses used in research.
Taking more doesn’t necessarily mean a bigger effect but we’re short on high-quality dose-response studies.
Can bicarb enhance athletic recovery and performance?
Taking bicarbonate before a session or race is likely to improve performance during high-intensity short-duration events lasting between ∼45-seconds and 8-minutes, and is also likely to improve muscle endurance “reps-to-failure” and repeated maximal sprint power.
The effect sizeAn effect size is a standardized measure of the magnitude of an effect of an intervention. Unlike p-values, effect sizes show how large the effect is and indicate how meaningful it might be. Common effect size measures include standardised mean difference (SMD), Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients. is small.
The effect appears to be similar between trained athletes and untrained folks, and between males and females; however, further research is needed in females because they are underrepresented among studies in this field.
Keep in mind: because there is moderate to high heterogeneityHeterogeneity shows how much the results in different studies in a meta-analysis vary from each other. It is measured as the percentage of variation (the I2 value). A rule of thumb: if I2 is roughly 25%, that indicates low heterogeneity (good), 50% is moderate, and 75% indicates high heterogeneity (bad). High heterogeneity means there’s more variability in effects between studies and, therefore, a less precise overall effect estimate. (variability) in effects between studies, and because there is a moderate to low quality of evidenceA low quality of evidence means that, in general, studies in this field have several limitations. This could be due to inconsistency in effects between studies, a large range of effect sizes between studies, and/or a high risk of bias (caused by inappropriate controls, a small number of studies, small numbers of participants, poor/absent randomisation processes, missing data, inappropriate methods/statistics). When the quality of evidence is low, there is more doubt and less confidence in the overall effect of an intervention, and new studies could easily change overall conclusions. The most effective way to enhance the quality of evidence is for scientists to conduct large, well-controlled, high-quality randomised controlled trials. with possible publication biasPublication bias in meta-analysis occurs when studies with significant results are more likely to be published than those with non-significant findings, leading to distorted conclusions. This bias can inflate effect sizes and misrepresent the true effectiveness of interventions, making it crucial to identify and correct for it in research., additional high-quality randomised controlled trialsThe “gold standard” approach for determining whether a treatment has a causal effect on an outcome of interest. In such a study, a sample of people representing the population of interest is randomised to receive the treatment or a no-treatment placebo (control), and the outcome of interest is measured before and after exposure to the treatment and control. are needed to increase the certaintyCertainty of evidence tells us how confident we are that the results reflect the true effect. It’s based on factors like study design, risk of bias, consistency, directness, and precision. High certainty means strong, consistent research. Low certainty means more doubt and less confidence, and that new studies could easily change the conclusions. (confidence) in the overall effect sizes reported in meta-analysesA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment..
To minimise the risk of consuming a supplement that contains prohibited substances, only choose products that have been independently tested (e.g., Informed Sport). And, remember: Supplements do not make athletes and do not replace training; they're just the icing on a very well-baked cake. Before reaching for pills and potions, optimise your training load and dial in your sleep, nutrition, and rest.
How to use this: If you’re targeting short, hard efforts — think track intervals, hill reps, OCR sprints, time-to-exhaustion tests — trial bicarb in training 1 to 3 hours pre-session at 0.2 to 0.3 grams per kilogram of body weight. Start low, split the dose if your gut is touchy, and don’t debut it on race day. For longer steady races, skip it — the juice probably isn’t worth the slosh.
The information I provide is not medical advice. Sodium bicarbonate can have side effects and might interact with other drugs, nutrients, and medical conditions (see here). If you are unsure, always consult your doctor to ensure that a specific supplement is safe for you to use.
Full list of meta-analyses examining bicarbonate for performance.
Here are the meta-analyses I've summarised above:
Acute effects of sodium bicarbonate ingestion on cycling time-trial performance: A systematic review and meta-analysis of randomized controlled trials. Lopes-Silva et al. (2023) Eur J Sport Sci
Effects of Ketone Monoester and Bicarbonate Co-Ingestion on Cycling Performance in WorldTour Cyclists. Ramos-Campo et al. (2023) Int J Sport Nutr Exerc Metab
Effects of Sodium Bicarbonate Ingestion on Measures of Wingate Test Performance: A Meta-Analysis. Jozo Grgic. J Am Nutr Assoc (2022)
Effect of sodium bicarbonate supplementation on two different performance indicators in sports: a systematic review with meta-analysis. Lino et al. (2021) Phys Act Nutr
Effect of sodium bicarbonate contribution on energy metabolism during exercise: a systematic review and meta-analysis. Calvo et al. (2021) J Int Soc Sports Nutr
Sodium bicarbonate supplementation and the female athlete: A brief commentary with small scale systematic review and meta-analysis. Saunders B, Oliveira LF, Dolan E, Durkalec-Michalski K, McNaughton L, Artioli GG, Swinton PA. Eur J Sport Sci (2021)
Effect of β-alanine and sodium bicarbonate co-supplementation on the body's buffering capacity and sports performance: A systematic review. Laura Gilsanz, Jaime López-Seoane, Sergio L Jiménez, Helios Pareja-Galeano. Crit Rev Food Sci Nutr (2021)
Extracellular Buffering Supplements to Improve Exercise Capacity and Performance: A Comprehensive Systematic Review and Meta-analysis. Luana Farias de Oliveira, Eimear Dolan, Paul A Swinton, Krzysztof Durkalec-Michalski, Guilherme G Artioli, Lars R McNaughton, Bryan Saunders. Sports Med (2021).
Effects of sodium bicarbonate supplementation on exercise performance: an umbrella review.
Jozo Grgic, Ivana Grgic, Juan Del Coso, Brad J Schoenfeld, Zeljko Pedisic. J Int Soc Sports Nutr (2021)
Effect of sodium bicarbonate supplementation on two different performance indicators in sports: a systematic review with meta-analysis. Lino RS, Lagares LS, Oliveira CVC, Queiroz CO, Pinto LLT, Almeida LAB, Bonfim ES, Santos CPCD. Phys Act Nutr (2021)
Effects of diet interventions, dietary supplements, and performance-enhancing substances on the performance of CrossFit-trained individuals: A systematic review of clinical studies. Dos Santos Quaresma MVL, Guazzelli Marques C, Nakamoto FP. Nutrition (2021)
A Systematic Review and Meta-analysis on Sodium Bicarbonate Administration and Equine Running Performance: Is it Time to Stop Horsing Around With Baking Soda? Denham J, Hulme A. J Equine Vet Sci (2020)
Effects of Sodium Bicarbonate Supplementation on Muscular Strength and Endurance: A Systematic Review and Meta-analysis. Grgic J, Rodriguez RF, Garofolini A, Saunders B, Bishop DJ, Schoenfeld BJ, Pedisic Z. Sports Med (2020)
Isolated effects of caffeine and sodium bicarbonate ingestion on performance in the Yo-Yo test: A systematic review and meta-analysis. Grgic J, Garofolini A, Pickering C, Duncan MJ, Tinsley GM, Del Coso J. J Sci Med Sport (2020)
The Impact of Preconditioning Strategies Designed to Improve 2000-m Rowing Ergometer Performance in Trained Rowers: A Systematic Review and Meta-Analysis. Turnes T, Cruz RSO, Caputo F, De Aguiar RA. Int J Sports Physiol Perform (2019)
The Impact of Sodium Bicarbonate on Performance in Response to Exercise Duration in Athletes: A Systematic Review. Hadzic M, Eckstein ML, Schugardt M. J Sports Sci Med (2019)
Acute and chronic effect of sodium bicarbonate ingestion on Wingate test performance: a systematic review and meta-analysis. Lopes-Silva JP, Reale R, Franchini E. J Sports Sci (2019)
β-alanine supplementation to improve exercise capacity and performance: a systematic review and meta-analysis. Saunders B, Elliott-Sale K, Artioli GG, Swinton PA, Dolan E, Roschel H, Sale C, Gualano B. Br J Sports Med (2017)
A systematic review of the efficacy of ergogenic aids for improving running performance. Schubert MM, Astorino TA. J Strength Cond Res (2013)
Practical recommendations for coaches and athletes: a meta-analysis of sodium bicarbonate use for athletic performance. Peart DJ, Siegler JC, Vince RV. J Strength Cond Res (2012)
Effects of acute alkalosis and acidosis on performance: a meta-analysis. Carr AJ, Hopkins WG, Gore CJ. Sports Med (2011)
Effects of sodium bicarbonate ingestion on anaerobic performance: a meta-analytic review. Matson LG, Tran ZV. Int J Sport Nutr (1993) .
Consult WADA’s prohibited list.
Cross-check your meds against the Global DRO drug reference list.
Only choose supplements that have been independently tested by Informed Sport or LabDoor. You are the only person responsible for what goes in your body. Ignorance is not an excuse! Stay educated. Be informed.
Nail your daily nutrition habits first, layer specific sports nutrition on top of that, and then start to consider supplements.
The information I provide is not medical advice. L-carnitine can have side effects and might interact with other drugs, nutrients, and medical conditions (see here). If you are unsure, always consult your doctor to ensure that a specific supplement is safe for you to use.
What is carnitine?
Carnitine is an amino acid predominantly found in muscle tissue, but it isn’t a building block of protein and it’s not coded by your genes. Your body can make it from lysine and methionine, and if you eat meat you’ll also get a chunk from food. Its job: to move fatty acids into mitochondria so they can be oxidized for energy. The gatekeeper for that process is the carnitine palmitoyltransferase system, which helps fat enter the mitochondria and then feed into beta-oxidation — a process that produces lots of ATP (energy). And, this is important because during rest and low to moderate-intensity exercise, the body predominantly “burns” fatty acids to produce energy (ATP).
In the world of medicine, carnitine is sometimes used in people with peripheral artery disease to help treat a symptom called “intermittent claudication” — jargon for achy calf pain during walking that eases when the person stops — which occurs because of poor blood flow and energy metabolism (muscle carnitine deficiency, which reduces fat metabolism). Several meta-analysesA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment. (see here, here, here, & here) show that oral or intravenous administration of either L-carnitine or propionyl-L-carnitine (a derivative) can help treat intermittent claudication and improve walking capacity in folks with peripheral artery disease.
In people with peripheral artery disease and in healthy folks, supplementing with L-carnitine or propionyl-L-carnitine can raise carnitine levels in muscle. Propionyl-L-carnitine can also form propionyl-CoA, which can be turned into succinyl-CoA and drop into the Krebs cycle to help produce extra energy (ATP). Furthermore, because people with peripheral artery disease often walk farther after taking it, athletes reasonably ask: “does this help running performance too?”. Carnitine certainly gained some notoriety for that purpose because it was one of the “supplements” that played a starring role in the Alberto Salazar–Mo Farah saga. But…
What is the scientific evidence on carnitine’s impact on athletic performance?
L-carnitine and propionyl-L-carnitine are generally considered to be safe to consume (see here, here, here, and here).
Short-term doses before exercise or daily use might help during high-intensity efforts (80% of V̇O2maxV̇O2max is the maximal rate of oxygen consumption your body can achieve during exercise. It is a measure of cardiorespiratory fitness and indicates the size of your engine, i.e., your maximal aerobic power, which contributes to endurance performance. or higher), but the evidence is limited and not super consistent.
Only a few studies have tested moderate-intensity work (below 80% of V̇O2max), and the study designs differ so much that it's hard to tell what’s truly going on.
Most tests were done when participants were fresh. We don’t know if the same effects show up when people are already fatigued — for example, a performance test after a long run.
There’s also very little data in trained athletes: we need more high-quality trials.
There are also two unanswered questions, and high-quality randomised controlled trialsThe “gold standard” approach for determining whether a treatment has a causal effect on an outcome of interest. In such a study, a sample of people representing the population of interest is randomised to receive the treatment or a no-treatment placebo (control), and the outcome of interest is measured before and after exposure to the treatment and control. are needed to answer them:
Does orally taken carnitine actually reach the muscles’ mitochondria in useful amounts?
Is propionyl-L-carnitine the better choice for performance?
One trial directly compared the two forms and found propionyl-L-carnitine led to better exercise capacity than L-carnitine (see Brevetti et al. 1992), but that was in people with peripheral artery disease, not athletes.
If you choose to use L-carnitine / propionyl-L-carnitine, a reasonable dose is:
3 to 4 grams about 60 to 90 minutes before exercise, or 2 to 3 grams per day for 9 to 24 weeks. These are doses used in studies, not a personal prescription.
Taking more doesn’t necessarily mean a bigger effect.
When supplementation is stopped, we don’t yet know how fast muscle levels fall back to baseline.
Can carnitine enhance athletic recovery and performance?
Moderate quality of evidenceA moderate quality of evidence means that, in general, studies in this field have some limitations. This could be due to somewhat inconsistent effects between studies, a moderate range of effect sizes between studies, and/or a moderate risk of bias (caused by a small to medium number of studies, small to medium numbers of participants, poorly described randomization processes, some missing data, some inappropriate methods/statistics). When the quality of evidence is moderate, there is some doubt and only moderate confidence in the overall effect of an intervention, and future studies could change overall conclusions. The best way to improve the quality of evidence is for scientists to conduct large, well-controlled, high-quality randomized controlled trials. shows that propionyl-L-carnitine is likely to improve walking distance in people with peripheral artery disease. However, this medical benefit does not automatically apply to trained athletes.
Although some evidence shows that L-carnitine taken daily or pre-session might help in high-intensity efforts, but overall it’s unlikely to boost performance in a meaningful way.
Due to insufficient research, it is unclear whether these effects are similar between trained athletes and untrained folks or between males and females.
Because there is not a high quality meta-analysisA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment., the overall effect sizeAn effect size is a standardized measure of the magnitude of an effect of an intervention. Unlike p-values, effect sizes show how large the effect is and indicate how meaningful it might be. Common effect size measures include standardised mean difference (SMD), Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients. is currently uncertain.
Keep in mind: there is also high heterogeneityHeterogeneity shows how much the results in different studies in a meta-analysis vary from each other. It is measured as the percentage of variation (the I2 value). A rule of thumb: if I2 is roughly 25%, that indicates low heterogeneity (good), 50% is moderate, and 75% indicates high heterogeneity (bad). High heterogeneity means there’s more variability in effects between studies and, therefore, a less precise overall effect estimate. (variability) in effects between studies, moderate/high risk of biasRisk of bias in a meta-analysis refers to the potential for systematic errors in the studies included in the analysis. Such errors can lead to misleading/invalid results, and unreliable conclusions. This can arise because of issues with the way participants are selected (randomisation), how data is collected and analysed, and how the results are reported., and possible publication biasPublication bias in meta-analysis occurs when studies with significant results are more likely to be published than those with non-significant findings, leading to distorted conclusions. This bias can inflate effect sizes and misrepresent the true effectiveness of interventions, making it crucial to identify and correct for it in research.. So, the overall certainty of evidenceCertainty of evidence tells us how confident we are that the results reflect the true effect. It’s based on factors like study design, risk of bias, consistency, directness, and precision. Low certainty means more doubt and less confidence, and that future studies could easily change the conclusions. High certainty means that the current evidence is so strong and consistent that future studies are unlikely to change conclusions. is lowA low quality of evidence means that, in general, studies in this field have several limitations. This could be due to inconsistency in effects between studies, a large range of effect sizes between studies, and/or a high risk of bias (caused by inappropriate controls, a small number of studies, small numbers of participants, poor/absent randomisation processes, missing data, inappropriate methods/statistics). When the quality of evidence is low, there is more doubt and less confidence in the overall effect of an intervention, and new studies could easily change overall conclusions. The most effective way to enhance the quality of evidence is for scientists to conduct large, well-controlled, high-quality randomised controlled trials.. Therefore, additional high-quality randomised controlled trialsThe “gold standard” approach for determining whether a treatment has a causal effect on an outcome of interest. In such a study, a sample of people representing the population of interest is randomised to receive the treatment or a no-treatment placebo (control), and the outcome of interest is measured before and after exposure to the treatment and control. are needed.
The nice part: carnitine doesn't appear to hurt recovery or performance. So, if you like it and believe it works for you, give it a whirl. But, remember that time and money spent trying to improve your performance with something that has no obvious benefit might be better spent optimising your training load, sleep habits, and dietary/nutritional choices.
To minimise the risk of consuming a supplement that contains prohibited substances, only choose products that have been independently tested (e.g., Informed Sport). And, remember: Supplements do not make athletes and do not replace training; they're just the icing on a very well-baked cake. Before reaching for pills and potions, optimise your training load and dial in your sleep, nutrition, and rest.
How to use this: If you want to self-experiment, keep it simple: try 3 to 4 grams about 60 to 90 minutes before a single key session, or 2 to 3 grams per day for at least a few weeks. Track something that matters to you (time to exhaustion, reps, race splits). If there’s no clear, consistent benefit after a few weeks, save your money and invest in good sleep, healthy nutrition, and ample rest.
Full list of meta-analyses examining carnitine for performance.
Here are the meta-analyses I've summarised above:
Clinical Effects of L-Carnitine Supplementation on Physical Performance in Healthy Subjects, the Key to Success in Rehabilitation: A Systematic Review and Meta-Analysis from the Rehabilitation Point of View. Vecchio et al. (2021) J Funct Morphol Kinesio
Effect of Acute and Chronic Oral l-Carnitine Supplementation on Exercise Performance Based on the Exercise Intensity: A Systematic Review. Mielgo-Ayuso et al. (2021) Nutrients
Consult WADA’s prohibited list.
Cross-check your meds against the Global DRO drug reference list.
Only choose supplements that have been independently tested by Informed Sport or LabDoor. You are the only person responsible for what goes in your body. Ignorance is not an excuse! Stay educated. Be informed.
Nail your daily nutrition habits first, layer specific sports nutrition on top of that, and then start to consider supplements.
The information I provide is not medical advice. Supplements can have side effects and might interact with other drugs, nutrients, and medical conditions. If you are unsure, always consult your doctor to ensure a specific supplement is safe for you to use.
What are ketones?
Ketones are small molecules your body makes — acetate, acetoacetate, and β-hydroxybutyrate (also called 3-hydroxybutyrate). In everyday life they hover in your blood in tiny amounts (below 0.5 millimoles per litre, 0.5 mM). Levels rise when your carb tank is low. That state is called ketosis and usually sits around 0.5 to 3 mM. You might reach ketosis during a long fast (about 12 hours without calories), a very long workout, or a very low-carb diet (under 50 grams per day). That’s called “physiological” ketosis, which is safe and normal, and not the same as ketoacidosis, which is a dangerous medical emergency seen in some people with diabetes when ketones can climb toward 10 mM or higher. Different thing, different vibe, call a doctor for that one.
When carbs are scarce, your liver turns fat (triglycerides and fatty acids) into ketones and ships them around the body—especially to your brain—so you can keep moving and thinking. Besides the physiological/pathophysiological events described above, you can also raise blood ketones by drinking them (see here & here). Products usually contain a ketone ester (for example, (R)-3-hydroxybutyl (R)-3-hydroxybutyrate) or a ketone precursor like R-1,3-butanediol. Some evidence shows that a single dose of ketones can decrease blood glucose concentrations, showing its potential for diabetes treatment. There are also studies showing how ketone supplementation may affect appetite and cognitive function in humans, but more high-quality studies are needed before we get carried away.
The first published exercise study using ketone supplementation reported higher fat burning and a faster time trial even when muscle glycogen levels were normal and carbohydrates were ingested during exercise (see Cox et al. 2016). Consequently, the media has gone nuts, athlete/team sponsorships are rife, and several companies started selling ketone-containing products. The most heavily marketed ketone supplement is the “drinkable ketone” from HVMN — KetoneIQ — which contains a ketone precursor (R-1,3-butanediol) that is converted to β-hydroxybutyrate (a ketone) in the body. If you follow pro cycling, you will hear a lot about this product because they sponsor a large number of the pro teams. But sexy marketing does not equal proof of benefit. So…
What is the scientific evidence on ketones’ impact on athletic performance?
Ketones are generally safe to consume for healthy adults.
Meta-analysesA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment. report that short-term (single dose) or longer-term (daily) use of ketone esters or ketone precursors doesn’t improve endurance performance during time-to-exhaustion and time trial tests that range from about 90 seconds to 2 hours (see Brookset al. 2022 and Valenzuela et al. 2020).
Across studies, ketone esters and ketone precursors perform about the same—neither reliably boosts endurance.
However, its difficult to make firm conclusions about the effects of ketones because of the large variability in designs and effects between studies (see Margolis et al. 2019, Brookset al. 2022 and Valenzuela et al. 2020). For example, test durations differ widely, fed versus fasted states vary, and many trials pair ketones with carbohydrate intake. When small benefits do turn up, they tend to show up with higher doses that raise blood β-hydroxybutyrate above about 2 mM (see Figure 4 in Margolis et al. 2020). However, because we don’t yet have good dose-response studies, that is also a shakey observation, not a rule.
So, the ketone supplement world seems to be one of those “first paper dogma” stories where the first paper published (Cox et al. 2016 Cell Metabolism) found a beneficial effect but subsequent studies did not confirm the findings yet the media kept echoing the narrative of “ketones are the bomb”.
That aside, there are some unanswered questions:
There’s currently no meta-analysisA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment. on strength outcomes with ketone supplements.
There’s also no meta-analysis on ultra-distance performance. Because ketones matter more when glycogen and blood glucose are low, ultras are a logical testing ground but right now that’s a big question mark. Because ketones can fuel the brain when glucose is scarce (Cunnane et al.), it has been proposed that ketones might help cognition under stress (fasting, hypoxia, hard exercise). Some rodent studies (see Pawlosky et al., Murray et al., Ahmad et al.) and a few human trials show benefits (see Evans et al., McClure et al., Waldman et al., Quinones et al., Kackley et al., Walsh et al., Krolak-Salmon et al.), but several others don’t (see Waldman et al., Waldman et al., McClure et al.) — so, more research is needed before we claim sharper late-race decision-making.
If you choose to use a ketone supplement, a reasonable dose is:
A pre-exercise dose that lifts blood β-hydroxybutyrate to at least 2 mM. Note: that suggestion mirrors doses used in research; it is not a magic threshold that definitely causes a benefit.
Can ketones enhance athletic recovery and performance?
Ketones are unlikely to improve performance or recovery in typical endurance settings.
The effect sizeAn effect size is a standardized measure of the magnitude of an effect of an intervention. Unlike p-values, effect sizes show how large the effect is and indicate how meaningful it might be. Common effect size measures include standardised mean difference (SMD), Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients. is trivial.
The effect appears to be similar between trained athletes and untrained folks, and between males and females; however, further research is needed in females because they are underrepresented among studies in this field.
Keep in mind: the studies are small and there is high heterogeneityHeterogeneity shows how much the results in different studies in a meta-analysis vary from each other. It is measured as the percentage of variation (the I2 value). A rule of thumb: if I2 is roughly 25%, that indicates low heterogeneity (good), 50% is moderate, and 75% indicates high heterogeneity (bad). High heterogeneity means there’s more variability in effects between studies and, therefore, a less precise overall effect estimate. (variability) in effects between studies, a moderate-to-high risk of biasRisk of bias in a meta-analysis refers to the potential for systematic errors in the studies included in the analysis. Such errors can lead to misleading/invalid results, and unreliable conclusions. This can arise because of issues with the way participants are selected (randomisation), how data is collected and analysed, and how the results are reported., and possible publication biasPublication bias in meta-analysis occurs when studies with significant results are more likely to be published than those with non-significant findings, leading to distorted conclusions. This bias can inflate effect sizes and misrepresent the true effectiveness of interventions, making it crucial to identify and correct for it in research.. So, the overall certainty of evidenceCertainty of evidence tells us how confident we are that the results reflect the true effect. It’s based on factors like study design, risk of bias, consistency, directness, and precision. Low certainty means more doubt and less confidence, and that future studies could easily change the conclusions. High certainty means that the current evidence is so strong and consistent that future studies are unlikely to change conclusions. is lowA low quality of evidence means that, in general, studies in this field have several limitations. This could be due to inconsistency in effects between studies, a large range of effect sizes between studies, and/or a high risk of bias (caused by inappropriate controls, a small number of studies, small numbers of participants, poor/absent randomisation processes, missing data, inappropriate methods/statistics). When the quality of evidence is low, there is more doubt and less confidence in the overall effect of an intervention, and new studies could easily change overall conclusions. The most effective way to enhance the quality of evidence is for scientists to conduct large, well-controlled, high-quality randomised controlled trials.. Therefore, additional high-quality randomised controlled trialsThe “gold standard” approach for determining whether a treatment has a causal effect on an outcome of interest. In such a study, a sample of people representing the population of interest is randomised to receive the treatment or a no-treatment placebo (control), and the outcome of interest is measured before and after exposure to the treatment and control. are needed to increase the certainty (confidence) in the overall effect sizes reported in meta-analysesA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment..
The nice part: ketones do not appear to have a detrimental effect on recovery or performance. So, if you like it and believe it works for you, give it a whirl. But, remember that time and money spent trying to improve your performance with something that has no obvious benefit might be better spent optimising your training load, sleep habits, and dietary/nutritional choices.
Additional trials on ultra-endurance performance are needed since this could feasibly be where ketones emerge to be beneficial, either direct performance benefits or effects on cognition function. Watch this space!
To minimise the risk of consuming a supplement that contains prohibited substances, only choose products that have been independently tested (e.g., Informed Sport). And, remember: Supplements do not make athletes and do not replace training; they're just the icing on a very well-baked cake. Before reaching for pills and potions, optimise your training load and dial in your sleep, nutrition, and rest.
How to use this: Treat ketones as an optional experiment for long training days or ultra builds. If you try them, take a pre-workout dose that reliably raises blood β-hydroxybutyrate above about 2 mM, test it in training (not race day first), and track how you feel, think, and perform. If there’s no clear benefit after a few trials, save your time and money to invest in things that definitely move the needle: good sleep, nutritious food, adequate rest, and an optimal training load.
The information I provide is not medical advice. Supplements can have side effects and might interact with other drugs, nutrients, and medical conditions. If you are unsure, always consult your doctor to ensure a specific supplement is safe for you to use.
Full list of meta-analyses examining ketones for performance.
Here are the meta-analyses I've summarised above:
Acute Ingestion of Ketone Monoesters and Precursors Do Not Enhance Endurance Exercise Performance: A Systematic Review and Meta-Analysis. Emma Brooks, Gilles Lamothe, Taniya S Nagpal, Pascal Imbeault, Kristi Adamo, Jameel Kara, Éric Doucet. Int J Sport Nutr Exerc Metab (2022).
Utility of Ketone Supplementation to Enhance Physical Performance: A Systematic Review. Margolis LM, O'Fallon KS. Adv Nutr (2020).
Acute Ketone Supplementation and Exercise Performance: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Valenzuela PL, Morales JS, Castillo-García A, Lucia A. Int J Sports Physiol Perform (2020).
Consult WADA’s prohibited list.
Cross-check your meds against the Global DRO drug reference list.
Only choose supplements that have been independently tested by Informed Sport or LabDoor. You are the only person responsible for what goes in your body. Ignorance is not an excuse! Stay educated. Be informed.
Nail your daily nutrition habits first, layer specific sports nutrition on top of that, and then start to consider supplements.
The information I provide is not medical advice. CBD and THC can have side effects and might interact with other drugs, nutrients, and medical conditions (see CBD here and THC/cannabis here). If you are unsure, always consult your doctor to ensure that a specific supplement is safe for you to use.
What are CBD, THC, and cannabis?
CBD (cannabidiol) and THC (tetrahydrocannabinol) belong to a class of chemicals called, cannabinoids. THC is the main cannabinoid that provides the relaxing “high” plus a bunch of other side effects (paranoia, sleepiness, short-term memory loss, dizziness, confusion, reduced coordination, slurred speech) when smoking/eating/vaping marijuana (or when eating “edibles” containing isolated THC). On the other hand, CBD is isolated from dried, crushed cannabis plants and does not have any psychoactive properties but is alleged to relieve pain, improve sleep, and reduce inflammation.
Cannabinoids have been used to develop some drugs. For example, CBD is the active ingredient in Epidiolex, which is prescribed to treat seizures in patients with rare forms of epilepsy; while THC is the active ingredient in Nabiximols/Sativex, which is used to treat pain in patients with multiple sclerosis. Beyond that, “medical marijuana” is now prescribed in some countries, while some folks recreationally use THC-containing “edibles” or smoke marijuana to relieve anxiety and pain caused by chronic disease. However, despite being a prescription drug in some countries, the overall effect and risk/benefit balance of marijuana is debated. All that said, business is booming for CBD and THC. And, the theoretical benefits of cannabinoids in sports are frequently reported. Plus, the world has gone wild for CBD oils and tinctures and rubs with abundant claims of greatest for athletes. So, the important question…
What is the scientific evidence on CBD’s, THC’s, and cannabis’ impact on athletic performance?
CBD and THC are generally safe to consume, but some studies indicate that chronic (long-term regular) use of THC or smoking cannabis is associated with addiction, and cognitive impairments.
That said, inhaling solid particles and other chemicals into your lungs — smoking (cigarettes or cannabis) — may impair lung function, which is not a smart athlete’s goal.
At the time of writing, CBD is not on WADA’s prohibited list but WADA does prohibit the in-competition use of other cannabinoids, including THC. Also, be aware that many CBD-containing products are contaminated with THC.
Effects of THC and cannabis:
Neither THC or cannabis improve exercise performance (either endurance or strength) or markers of performance (e.g. V̇O2max).
Furthermore, when taken before exercise, THC and cannabis increase breathing rate, impair balance and reduce strength and maximal work capacity — reasons not to indulge before exercise.
Some evidence suggests that THC and cannabis cause psychotropic enhancement and pain reduction. This may aid some sports and probably explains why THC and cannabis remain on WADA’s “in competition” prohibited list. But the side effects of THC/cannabis (e.g. sleepiness, short-term memory loss, dizziness, confusion, reduced coordination, slurred speech) may raise a safety issue in some sports; another reason they exist on WADA’s prohibited list. Furthermore, cannabis is an illegal drug in many countries; another reason WADA is keeping it on the prohibited list.
Effects of CBD:
CBD is a very well-marketed product that “treats all ailments” and “improves all aspects” of human physiology. At this time, those effects are anecdotal and evidence from high-quality randomised controlled trials does not exist to support the narrative.
But an absence of evidence is not evidence of absence. At this time, because of the lack of randomised controlled trials, there is not a meta-analysisA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment. examining the effect of CBD on performance or recovery after exercise (that will no doubt change soon).
In the meantime, a 2020 narrative review by McCartney and colleagues dug into the evidence, concluding that “the available evidence is preliminary, at times inconsistent, and largely based on preclinical studies involving laboratory animals”.
A 2024 meta-analysis by Lo et al. suggests that acute CBD consumption may slightly increase feelings of sedation compared to placebo but does not significantly impact performance across a range of cognitive domains. Therefore, the acute use of CBD (in the absence of THC or other drugs) is unlikely to lead to functional impairment. That said, the long-term effects of daily CBD intake on neurocognitive function have not been fully examined.
One problem with the widespread outbreak of over-the-counter CBD products is that CBD is treated as a dietary supplement and, therefore, CBD products are monitored but not regulated. One study analysed the CBD content of an array of CBD oils and of the 25 products, only 3 were within 20% of the claimed amount, 15 were well below the claimed amount, 3 contained THC in amounts above the legal limit, and 5 products did not state the CBD content at all. This is a problem for athletes wanting to use CBD products, so be warned.
Can CBD, THC, and cannabis enhance athletic recovery and performance?
For CBD, only anecdotes promote its use and the evidence suggests that CBD is highly unlikely to enhance performance. THC and cannabis are also highly unlikely to improve performance; furthermore, cannabis is more likely to impair performance than be of any benefit.
Precise effect sizesAn effect size is a standardized measure of the magnitude of an effect of an intervention. Unlike p-values, effect sizes show how large the effect is and indicate how meaningful it might be. Common effect size measures include standardised mean difference (SMD), Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients. is unclear because there is no meta-analysisA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment..
The effects are likely to be similar between trained athletes and untrained folks, and between males and females, but further comparative research is needed for increased confidence.
Keep in mind: despite the lack of meta-analyses, systematic reviewsA systematic review answers a specific research question by systematically collating all known experimental evidence, which is collected according to pre-specified eligibility criteria. A systematic review helps inform decisions, guidelines, and policy. report high heterogeneityHeterogeneity shows how much the results in different studies in a meta-analysis vary from each other. It is measured as the percentage of variation (the I2 value). A rule of thumb: if I2 is roughly 25%, that indicates low heterogeneity (good), 50% is moderate, and 75% indicates high heterogeneity (bad). High heterogeneity means there’s more variability in effects between studies and, therefore, a less precise overall effect estimate. (variability) in study designs and effects between studies and a moderate-to-high risk of biasRisk of bias in a meta-analysis refers to the potential for systematic errors in the studies included in the analysis. Such errors can lead to misleading/invalid results, and unreliable conclusions. This can arise because of issues with the way participants are selected (randomisation), how data is collected and analysed, and how the results are reported.. This suggests that the overall certainty of evidenceCertainty of evidence tells us how confident we are that the results reflect the true effect. It’s based on factors like study design, risk of bias, consistency, directness, and precision. Low certainty means more doubt and less confidence, and that future studies could easily change the conclusions. High certainty means that the current evidence is so strong and consistent that future studies are unlikely to change conclusions. is lowA low quality of evidence means that, in general, studies in this field have several limitations. This could be due to inconsistency in effects between studies, a large range of effect sizes between studies, and/or a high risk of bias (caused by inappropriate controls, a small number of studies, small numbers of participants, poor/absent randomisation processes, missing data, inappropriate methods/statistics). When the quality of evidence is low, there is more doubt and less confidence in the overall effect of an intervention, and new studies could easily change overall conclusions. The most effective way to enhance the quality of evidence is for scientists to conduct large, well-controlled, high-quality randomised controlled trials.. Additional high-quality randomised controlled trialsThe “gold standard” approach for determining whether a treatment has a causal effect on an outcome of interest. In such a study, a sample of people representing the population of interest is randomised to receive the treatment or a no-treatment placebo (control), and the outcome of interest is measured before and after exposure to the treatment and control. are needed to conduct a meta-analysisA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment. and to increase the certainty (confidence) in the overall effect.
The nice part: CBD doesn't appear to hurt recovery or performance. So, if you like it and believe it works for you, give it a whirl. But, remember that time and money spent trying to improve your performance with something that has no obvious benefit might be better spent optimising your training load, sleep habits, and dietary/nutritional choices.
However, because cannabis is more likely to impair performance than be of any benefit, it would be wise to avoid THC or cannabis before exercise. Plus, because THC and cannabis are drugs, consult WADA’s prohibited list before use.
To minimise the risk of consuming a supplement that contains prohibited substances, only choose products that have been independently tested (e.g., Informed Sport). And, remember: Supplements do not make athletes and do not replace training; they're just the icing on a very well-baked cake. Before reaching for pills and potions, optimise your training load and dial in your sleep, nutrition, and rest.
The information I provide is not medical advice. CBD and THC can have side effects and might interact with other drugs, nutrients, and medical conditions (see CBD here and THC/cannabis here). If you are unsure, always consult your doctor to ensure that a specific supplement is safe for you to use.
Full list of meta-analyses examining CBD, THC, and cannabis for performance.
Here are the meta-analyses I've summarised above:
The Effect of Cannabidiol on Performance and Post-Load Recovery among Healthy and Physically Active Individuals: A Systematic Review. Bezuglov et al. (2024) Nutrients.
Does acute cannabidiol (CBD) use impair performance? A meta-analysis and comparison with placebo and delta-9-tetrahydrocannabinol (THC). Lo et al. (2024) Neuropsychopharmacology.
Chronic cannabis consumption and physical exercise performance in healthy adults: a systematic review. Andrew Kramer, Justin Sinclair, Lara Sharpe, Jerome Sarris. J Cannabis Res (2022)
Acute effects of cannabis consumption on exercise performance: a systematic and umbrella review. Charron J, Carey V, Marcotte L'heureux V, Roy P, Comtois AS, Ferland PM. J Sports Med Phys Fitness (2021).
Cannabis Use and Sport: A Systematic Review. Shgufta Docter, Moin Khan, Chetan Gohal, Bheeshma Ravi, Mohit Bhandari, Rajiv Gandhi, Timothy Leroux. Sports Health (2020).
Chronic cannabis consumption and physical exercise performance in healthy adults: a systematic review. Kramer A, Sinclair J, Sharpe L, Sarris J. J Cannabis Res (2020).
Cannabis: Exercise performance and sport. A systematic review. Kennedy MC. J Sci Med Sport (2017).
Consult WADA’s prohibited list.
Cross-check your meds against the Global DRO drug reference list.
Only choose supplements that have been independently tested by Informed Sport or LabDoor. You are the only person responsible for what goes in your body. Ignorance is not an excuse! Stay educated. Be informed.
Nail your daily nutrition habits first, layer specific sports nutrition on top of that, and then start to consider supplements.
The information I provide is not medical advice. Omega-3 fatty acids can have side effects and might interact with other drugs, nutrients, and medical conditions (see here). If you are unsure, always consult your doctor to ensure that a specific supplement is safe for you to use.
What are omega-3s and fish oils?
Fish oils are rich in DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid), which are long-chain polyunsaturated n–3 (ω-3) fatty acids (aka omega-3 fatty acids) found in oily fish like salmon, herring, mackerel, and tuna, and in predatory fish that eat oily fish (e.g. swordfish, shark, tuna). DHA and EPA are also found in algae and in high amounts in flax seeds, chia seeds, hemp seeds, and walnuts.
In our body, DHA and EPA have a number of roles. EPA primarily acts as a precursor in the synthesis of prostaglandins and leukotrienes, which are molecules involved in inflammation and immune function. Meanwhile, DHA primary acts as a structural component in the cerebral cortex, skin, and retina. But, while both EPA and DHA are important fatty acids, neither are classified as essential fatty acidsEssential fatty acids are fatty acids that must be obtained in our diet because our body cannot synthesise them in sufficient quantities to maintain normal bodily function. because our body can synthesise them in adequate amounts to maintain normal function, but only if you have an adequate dietary source of another omega-3 fatty acid, called alpha-linolenic acid (aka ALA, one of the two essential fatty acids in humans along with linoleic acid). Alpha-linolenic acid is found in chia seeds and flax seeds but, in humans, the synthesis efficiency of alpha-linolenic acid to EPA and DHA is rather poor, hence the dietary recommendation to consume foods containing ALA, DHA and EPA.
Because of the abundance of omega-3 fatty acids in several foods, it is likely that you’ve been getting your daily fix of omega-3s for years. And, because we are under the perilous dietary fallacies of our elders, you might have been subjected to that spoonful of cod liver oil* your mum used to trick you into eating every morning as a kid. (*Note: cod liver oil is not only rich in DHA and EPA but also vitamins A and E; and, it tastes like sh*t — I hated my mum 40 years ago.) But, since many folks’ diet is subpar and since many folks probably don’t eat fish or seeds, it is also likely that many folks aren’t getting any DHA, EPA, or alpha-linolenic acid (ALA) in their diet. Therefore, omega-3s and fish oils have become very popular dietary supplements and supplementation may be necessary for people whose diet lacks foods containing DHA, EPA, and ALA. Beyond that, it is very difficult to ignore brand marketing campaigns regularly plugging fish oil products for athlete recovery and/or performance — on that note, the important question is…
What is the scientific evidence on omega-3’s and fish oil’s impact on athletic performance?
Please note that this summary is about exercise performance/recovery, not disease risk, prevention, or treatment. To go deep on the effects of omega-3s (DHA and EPA) or fish oils on general health, please check out examine.com/supplements/fish-oil and examine.com/supplements/omega-3. I consider Examine a carefully-researched and trusted resource. (For full disclosure, I’ve worked as a researcher and medical writer for Examine since October 2022, but do not receive royalties/bonuses for these referals.)
The adequate requirement for dietary intake of EPA, DHA, ALA, and linoleic acid is unknown but the adequate intake for adults, based on population averages, is 250 milligrams (mg) per day for DHA+EPA (source: Dietary Reference Values for the EU). Fish oils are generally safe to consume. That said, oily fish and fish oils can be contaminated with heavy metals and fat-soluble pollutants but the benefits of fish intake are generally considered to far outweigh the potential risks. Also note that liver-derived fish oil contains vitamin A, which can be toxic in high doses so there is an upper limit of ~3000 micrograms (μg) per day in adults (source: Dietary Reference Values for the EU).
For dietary reference values (DRVs) in Europe, consult efsa.europa.eu/drvs/index.htm. Or click here to view all DRVs for vitamins, minerals, and fatty acids (DHA, EPA, and ALA). And, to search for the vitamin/mineral content of specific foods, consult fdc.nal.usda.gov/fdc-app.html.
In younger adults aged 18 to 55, omega-3 (DHA + EPA) supplementation does not improve muscle hypertrophy, muscle strength or skeletal muscle biomarkers of inflammation and muscle damage beyond those obtained by strength training. There is no current systematic review on endurance performance.
But…
Omega-3 (DHA + EPA) supplementation does improve recovery of muscle soreness (self-reported feelings of soreness) and range of motion following exercise-induced muscle damage.
In older adults (55 years +), omega-3 (DHA + EPA) supplementation does not affect walking performance or upper-body strength but may increase lower-body strength and lower-body functional performance (get-up-and-go & sit-to-stand tests).
The effects of omega-3 supplementation in older adults are found in the presence and absence of resistance training, suggesting that older adults who cannot or do not exercise may benefit from omega-3 supplementation.
But…
The range of omega-3 doses used is large — e.g. EPA ranging from 300 to 2400 mg/d and DHA from 400 to 1500 mg/d — and there is large between-study heterogeneity (variability) and pooling of studies using various blends of supplements (e.g. fish oils, DHA, EPA, ALA, and linoleic acid). Furthermore, there is evidence of publication bias toward only positive findings being reported.
It is also currently unclear whether people enrolled in the studies had a prior omega-3 deficiency (diet lacking omega-3-containing foods) upon enrollment in the studies. If this was the case, then the omega-3 supplement would simply be replacing what is missing.
More high-quality randomised controlled trials are needed and dose responses need to be clarified.
If you choose to use omega-3s (DHA and EPA) or fish oils, a reasonable dose is:
~250 milligrams (mg) per day for combined EPA and DHA. A 1 gram (or 1000 milligrams; mg) fish oil supplement typically contains ~300 mg of combined EPA and DHA. But always check the nutritional label of your fish oil supplement. Note: this is based on the estimated adequate requirement for dietary intake (source: Dietary Reference Values for the EU). The effective dose for recovery and performance has not yet been clearly defined by research.
This is equivalent to ~2 × 100-gram portions of cooked salmon per week (source: fdc.nal.usda.gov/fdc-app.html) or ~1 to 2 grams of dried chia seeds per day (source: fdc.nal.usda.gov/fdc-app.html).
Taking more doesn’t necessarily mean a bigger effect and dietary supplements like omega-3s and fish oils are intended as a supplement to, not a replacement for, real food.
Can omega-3s and fish oils enhance athletic recovery and performance?
A daily omega-3 or fish oil supplement is highly unlikely to improve performance, except in people who are of older age (>55 years) and/or have a DHA or EPA deficiency.
For example, a daily omega-3 or fish oil supplement is likely to improve lean mass and muscle strength in older-aged adults, but not in younger adults.
A daily omega-3 or fish oil supplement is also likely to help alleviate feelings of muscle soreness and restore range of motion following muscle-damaging exercise. BUT, remember: trying to blunt soreness and inflammation after exercise may also blunt the very processes that are causing adaptations to exercise — read all about that at veohtu.com/NSAIDs.
The effect sizeAn effect size is a standardized measure of the magnitude of an effect of an intervention. Unlike p-values, effect sizes show how large the effect is and indicate how meaningful it might be. Common effect size measures include standardised mean difference (SMD), Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients. is trivial-to-small for the benefit to lean mass and muscle strength in older-aged adults, and small-to-moderate for the benefit to muscle soreness and range of motion following muscle-damaging exercise.
These effects appear to be similar between trained athletes and untrained folks, and between males and females.
Keep in mind: there is high heterogeneityHeterogeneity shows how much the results in different studies in a meta-analysis vary from each other. It is measured as the percentage of variation (the I2 value). A rule of thumb: if I2 is roughly 25%, that indicates low heterogeneity (good), 50% is moderate, and 75% indicates high heterogeneity (bad). High heterogeneity means there’s more variability in effects between studies and, therefore, a less precise overall effect estimate. (variability) in study designs and effect sizes between studies, a high risk of biasRisk of bias in a meta-analysis refers to the potential for systematic errors in the studies included in the analysis. Such errors can lead to misleading/invalid results, and unreliable conclusions. This can arise because of issues with the way participants are selected (randomisation), how data is collected and analysed, and how the results are reported., and possible publication biasPublication bias in meta-analysis occurs when studies with significant results are more likely to be published than those with non-significant findings, leading to distorted conclusions. This bias can inflate effect sizes and misrepresent the true effectiveness of interventions, making it crucial to identify and correct for it in research.. So, the overall certainty of evidenceCertainty of evidence tells us how confident we are that the results reflect the true effect. It’s based on factors like study design, risk of bias, consistency, directness, and precision. Low certainty means more doubt and less confidence, and that future studies could easily change the conclusions. High certainty means that the current evidence is so strong and consistent that future studies are unlikely to change conclusions. is lowA low quality of evidence means that, in general, studies in this field have several limitations. This could be due to inconsistency in effects between studies, a large range of effect sizes between studies, and/or a high risk of bias (caused by inappropriate controls, a small number of studies, small numbers of participants, poor/absent randomisation processes, missing data, inappropriate methods/statistics). When the quality of evidence is low, there is more doubt and less confidence in the overall effect of an intervention, and new studies could easily change overall conclusions. The most effective way to enhance the quality of evidence is for scientists to conduct large, well-controlled, high-quality randomised controlled trials.. Therefore, additional high-quality randomised controlled trialsThe “gold standard” approach for determining whether a treatment has a causal effect on an outcome of interest. In such a study, a sample of people representing the population of interest is randomised to receive the treatment or a no-treatment placebo (control), and the outcome of interest is measured before and after exposure to the treatment and control. are needed to increase the certainty (confidence) in the overall effect sizes reported in meta-analysesA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment..
The nice part: omega-3s and fish oils do not appear to have a detrimental effect on recovery or performance. So, if you like them and believe they work for you, give em a whirl. But, remember that time and money spent trying to improve your performance or recovery with something that has no obvious benefit might be better spent optimising your training load, sleep habits, and dietary/nutritional choices.
If your habitual diet is deficient in foods containing DHA, EPA, or ALA (e.g., oily fish, seeds, etc.) then an omega-3/fish oil supplement could be sensible, under the direction of your doctor or a dietitian. As with any dietary supplement, “taking more does not equal a bigger effect” and a dietary supplement is intended as a supplement to, not a replacement for, real food — learn how to establish a healthy eating pattern at veohtu.com/healthyeatingpattern.
To minimise the risk of consuming a supplement that contains prohibited substances, only choose products that have been independently tested (e.g., Informed Sport). And, remember: Supplements do not make athletes and do not replace training; they're just the icing on a very well-baked cake. Before reaching for pills and potions, optimise your training load and dial in your sleep, nutrition, and rest.
The information I provide is not medical advice. Omega-3 fatty acids can have side effects and might interact with other drugs, nutrients, and medical conditions (see here). If you are unsure, always consult your doctor to ensure that a specific supplement is safe for you to use.
Full list of meta-analyses examining omega-3s and fish oils for performance.
Here are the meta-analyses I've summarised above:
Examining the Influence of Omega-3 Fatty Acids on Performance, Recovery, and Injury Management for Health Optimization: A Systematic Review Focused on Military Service Members. Rittenhouse et al. (2025) Nutrients.
Omega-3 Fatty Acid Supplementation on Post-Exercise Inflammation, Muscle Damage, Oxidative Response, and Sports Performance in Physically Healthy Adults-A Systematic Review of Randomized Controlled Trials. Fernández-Lázaro et al. (2024) Nutrients
Effects of Omega-3 fatty acids supplementation and resistance training on skeletal muscle. Uchida et al. (2024) Clin Nutr ESPEN
Effects of Omega-3 Fatty Acid Supplementation on Skeletal Muscle Mass and Strength in Adults: A Systematic Review. Moon et al. (2023) Clin Nutr Res
Effects of Omega-3 Supplementation Alone and Combined with Resistance Exercise on Skeletal Muscle in Older Adults: A Systematic Review and Meta-Analysis. Stephen M Cornish Dean M Cordingley, Keely A Shaw, Scott C Forbes, Taylor Leonhardt, Ainsley Bristol, Darren G Candow, Philip D Chilibeck. Nutrients (2022)
The effect of long chain omega-3 polyunsaturated fatty acids on muscle mass and function in sarcopenia: A scoping systematic review and meta-analysis. Julia K Bird, Barbara Troesch, Ines Warnke, Philip C Calder. Clin Nutr ESPEN (2021)
Effect of omega-3 fatty acids supplementation on indirect blood markers of exercise-induced muscle damage: Systematic review and meta-analysis of randomized controlled trials. Gao Xin, Hesam Eshaghi. Food Sci Nutr (2021)
N-3 PUFA as an ergogenic supplement modulating muscle hypertrophy and strength: a systematic review. López-Seoane J, Martinez-Ferran M, Romero-Morales C, Pareja-Galeano H. Crit Rev Food Sci Nutr (2021).
The effect of fish oil supplementation on the promotion and preservation of lean body mass, strength, and recovery from physiological stress in young, healthy adults: a systematic review. Heileson JL, Funderburk LK. Nutr Rev (2020).
Are There Benefits from the Use of Fish Oil Supplements in Athletes? A Systematic Review. Lewis NA, Daniels D, Calder PC, Castell LM, Pedlar CR. Adv Nutr (2020).
Omega-3 Polyunsaturated Fatty Acid Supplementation for Reducing Muscle Soreness after Eccentric Exercise: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Zheng-Tao Lv, Jin-Ming Zhang, Wen-Tao Zh. Biomed Res Int (2020)
Response to exercise in older adults who take supplements of antioxidants and/or omega-3 polyunsaturated fatty acids: A systematic review. Rosario Pastor, Josep A Tur. Biochem Pharmacol (2020)
Consult WADA’s prohibited list.
Cross-check your meds against the Global DRO drug reference list.
Only choose supplements that have been independently tested by Informed Sport or LabDoor. You are the only person responsible for what goes in your body. Ignorance is not an excuse! Stay educated. Be informed.
Nail your daily nutrition habits first, layer specific sports nutrition on top of that, and then start to consider supplements.
The information I provide is not medical advice. Vitamin D can have side effects and might interact with other drugs, nutrients, and medical conditions (see here). If you are unsure, always consult your doctor to ensure that a specific supplement is safe for you to use.
What is vitamin D?
Vitamin D is a fat-soluble vitamin that primarily regulates calcium (and phosphate and magnesium) metabolism to facilitate bone growth and maintain bone health. Vitamin D deficiency causes bone irregularities, which in the extreme can cause rickets (impaired bone growth) in children and osteomalacia (soft bones & weak muscles) and osteoporosis (low bone density & fractures) in adults. Our skin cells can synthesise cholecalciferol (aka vitamin D3) when our skin is exposed to sunlight (UV-B radiation), but we also obtain vitamin D3 in our diet from foods like egg yolks, liver, oily fish (salmon, mackerel, sardines), and cod liver oil, as well as from foods that have been “fortified” with vitamin D3 (like some breakfast cereals and milk).
But vitamin D synthesis and metabolism are super complex and confusing. When synthesised in the skin or eaten, cholecalciferol (vitamin D3) travels in the blood to the liver where it is “hydroxylated” (a hydroxyl group, —OH, is added) to produce a prohormone called calcifediol (aka 25-hydroxyvitamin D aka 25(OH)D). Calcifediol then leaves the liver and travels in the blood to your kidneys, where it is further “hydroxylated” to produce the active “hormonal” form of vitamin D, called calcitriol (1,25(OH)2D). Calcitriol is released by the kidney into the blood and then acts like a hormone, binding to vitamin D receptors on various tissues in the body to cause its effects. Furthermore, calcitriol is also produced in some immune cells where it plays a role in innate immunity.
Phew!
The prevalence of vitamin D deficiency is widely studied and, likely due to poor dietary habits and low exposure to direct sunlight, is actually pretty high — ~20% in Australia, ~68% across 5 South-East Asian countries, ~40% in the USA, ~34% in Scotland, and ~18% across Africa, etc. But, it is important to note that prevalence estimates massively vary by season.
Due to the high prevalence of vitamin D deficiency, vitamin D is commonly prescribed as a dietary supplement to bring bodily levels of cholecalciferol (aka vitamin D3) back up to normal. However, vitamin D supplements are also freely available over the counter, which creates a problem because vitamin D is fat-soluble and, therefore, is stored in the body and can be toxic when supplemented in high amounts. Interestingly, the 2013-14 NHANES (National Health and Nutrition Examination Survey) survey found that 18% of American adults exceeded 1000 IU (international units) of supplemental vitamin D per day, which is more than twice the US RDA (recommended daily amount), and that 3% took more than 4000 IU per day, which exceeds the upper tolerable limit and, therefore, increases the risk of adverse effects. The 1999-2000 NHANES survey found that just 0.3% and 0.1% of the population exceeded 1000 or 4000 IUs daily, indicating that intentional (and excessive) vitamin D supplementation has increased dramatically.
Vitamin D has many physiological roles and is essential for maintaining health. Systematic reviewsA systematic review answers a specific research question by systematically collating all known experimental evidence, which is collected according to pre-specified eligibility criteria. A systematic review helps inform decisions, guidelines, and policy. and meta-analysesA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment. have examined the association of blood concentrations of the vitamin D prohormone, calcifediol (or 25(OH)D) with various health outcomes — low 25(OH)D is associated with higher all-cause and cardiovascular-related risk of dying (aka mortality; see here & here), and a greater risk of severe infections (sepsis), cardiovascular disease, type 2 diabetes (see here & here), gestational diabetes, and dementia. But, associations do not prove that low vitamin D is causal in disease nor do they prove that vitamin supplementation will prevent or treat disease. Fortunately, systematic reviews and meta-analyses have determined the effect of vitamin D supplementation on disease…
Vitamin D supplementation doesn’t lower the risk of death from any cause (aka all-cause mortality) in the general population (see here, here, & here) nor does it lower the risk of cardiovascular disease (CVD) or CVD end-points (myocardial infarction, stroke, CVD mortality). But, Vitamin D supplementation may lower cancer-related risk of death, all-cause mortality in elderly folks, risk of diabetes in folks with prediabetes (see here, here, & here), and may help improve blood glucose control in patients with type 2 diabetes (see here & here).
NOTE: At this time, the effect of vitamin D supplementation on cognitive decline in dementia has not been systematically reviewed.
To summarise the above, vitamin D deficiency is associated with disease risk and supplementation may reduce the risk for some conditions. But, importantly, several of the meta-analyses found that the effects of vitamin D supplementation were only (or most) pronounced in folks who had vitamin D deficiency (blood 25-(OH)D <30 ng/ml) — i.e. supplementation was simply bringing vitamin D back to healthy levels.
Vitamin D has become a very popular dietary supplement and supplementation can be necessary for people who have a vitamin D deficiency (caused by a lack of daily sunlight, a dietary lack of foods containing vitamin D, or an irregularity of vitamin D metabolism). As of 2020, Public Health England, the health authority in the cloudy and sunlight-deficient UK, now recommends that all people who don’t obtain sufficient vitamin D in their diet should take a vitamin D supplement in the autumn and winter months (when sunlight is nonexistent, which is a normal day in the life of a Brit). However, the optimal vitamin D supplementation dose and the optimal dietary vitamin D intake are currently uncertain (see here). All that said, certain populations — children and adolescents aged 1 to 18 years, adults aged 75 years and older, pregnant women, people with intestinal disorders, etc. — have an increased risk of vitamin D deficiency (see here), so if you suspect you have a vitamin D deficiency, consult your doctor who can assess your vitamin D status by ordering a blood test for 25(OH)D (25-hydroxyvitamin D). A plasma concentration of <30 ng/ml indicates deficiency and your doctor may prescribe you a vitamin D supplement based on your results.
NOTE: you will see many names assigned to a vitamin D blood test — a 25-OH vitamin D blood test, cholecalciferol (vitamin D3) test, ergocalciferol (vitamin D2) test, calcidiol test, vitamin D2 test, or vitamin D3 test — which all assess a different aspect of vitamin D metabolism.
Since vitamin D receptors and vitamin D-related metabolites have been discovered in skeletal muscle and given that vitamin D regulates calcium metabolism and calcium is essential for muscle contraction, it is not absurd to hypothesise a role for vitamin D in muscle function. Indeed, a 2013 systematic review found that the blood concentration of 25(OH)D (25-hydroxyvitamin D, aka calcifediol) is associated with muscle strength. Since vitamin D deficiency is not rare, it is also not absurd to hypothesise that vitamin D supplementation may help performance — no doubt you have noticed the outbreak of brand marketing campaigns regularly plugging vitamin D products for athlete recovery and/or performance. So, the important question is…
What is the scientific evidence on vitamin D’s impact on athletic performance?
Please note that this summary is about exercise performance/recovery, not disease risk, prevention, or treatment. To go deep on the effects of vitamin D on general health, please check out examine.com/supplements/vitamin-d. I consider Examine a carefully-researched and trusted resource. (For full disclosure, I’ve worked as a researcher and medical writer for Examine since October 2022, but do not receive royalties/bonuses for these referals.)
The adequate requirement for dietary intake of vitamin D is unknown but the adequate intake for adults, based on population averages, is 15 micrograms (μg) per day (~600 IU/day) for vitamin D in the form of ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3). Vitamin D is generally safe to consume but there is a tolerable upper intake level of 100 μg per day (~4000 IU/day). Source: Dietary Reference Values for the EU.
For dietary reference values (DRVs) in Europe, consult efsa.europa.eu/drvs/index.htm. Or click here to view all DRVs for vitamins, minerals, and fatty acids (DHA, EPA, and ALA). And, to search for the vitamin/mineral content of specific foods, consult fdc.nal.usda.gov/fdc-app.html.
In postmenopausal women, daily vitamin D supplementation (~800 to 1,000 IU per day of cholecalciferol, aka vitamin D3) without daily exercise does not improve functional performance (timed up-and-go) but can induce small increases in hand-grip strength, a biomarker of whole body muscle strength. However, this effect is most pronounced in women over 60 years of age, women who do not take calcium supplementation, and women with vitamin D deficiency (blood 25(OH)D <30 ng/ml).
In older adults (aged 50 or older), daily vitamin D supplementation (~800 to 1,000 IU per day of cholecalciferol) without daily exercise does not improve muscle strength, functional performance (timed up-and-go), or lean body mass (a biomarker for muscle mass).
But…
In older adults, daily vitamin D supplementation combined with regular strength training may improve muscle strength beyond strength training alone. More high-quality studies are needed in this area.
In younger adults (~18 to 50 years old), the effects of daily vitamin D supplementation on muscle strength are trivial and there are no effects on muscle mass or muscle power. But, greater benefits are seen in folks with vitamin D deficiency (blood 25(OH)D <30 ng/ml). More high-quality studies are needed in this area.
In adults of all ages, daily vitamin D supplementation has a moderate effect sizeAn effect size is a quantitative measure of the magnitude of a relationship or difference between groups in a study. Unlike p-values, effect sizes show how large or meaningful that effect is. Common effect size measures include Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients. on preventing the rise in blood creatine kinase levels after exercise-induced muscle damage but it does not help prevent the impairment in muscle strength following exercise-induced muscle damage. Further evidence also shows that daily vitamin D supplementation (at least 2000 IU/day for at least 1 week) can attenuate post-exercise muscle damage and inflammation (see Rojano-Ortega et al. 2023). However, further high quality randomised controlled trials are required to tackle this topic.
In athletes, daily vitamin D supplementation combined with regular training does not improve performance. Some data show beneficial effects on lower-limb but not upper-limb muscle strength and some data shows beneficial effects on athletes who train indoors. But, between-study heterogeneity (variability) in study designs is large and more high-quality studies are needed, especially examining athletes with and without vitamin D deficiency and athletes located in different geographical latitudes and climates (and, therefore, different exposures to UV light).
If you choose to use vitamin D, a reasonable dose is:
~15 micrograms (μg) or ~600 international units (IU) of cholecalciferol (vitamin D3) every day. Note: this is based on effective doses used in research.
This is equivalent to ~30-minutes of skin exposure to the sun each day.
Sometimes the amount of vitamin D is expressed in micrograms (μg) or International Units (IU) — 1 μg of vitamin D is equal to 40 IU. Therefore, a reasonable daily dose of 15 μg/day is equal to 600 IU/day and the tolerable upper intake level of 100 μg/day is equal to 4000 IU/day.
Taking more doesn’t necessarily mean a bigger effect and dietary supplements like vitamin D are intended as a supplement to, not a replacement for, real food.
Can vitamin D enhance athletic recovery and performance?
Vitamin D is unlikely to improve recovery or performance if your vitamin D status is in the healthy range.
That said, in older-aged people, supplementation with vitamin D alongside strength training is likely to increase muscle strength compared to strength training alone.
Similarly, in people with a vitamin D deficiency (blood 25OHD <30 ng/ml), supplementation with vitamin D alongside strength training is likely to increase muscle strength compared to strength training alone. However, supplementation might simply be restoring muscle strength back to the level it would be if you had a healthy blood vitamin D level.
If you suspect you have a vitamin D deficiency because of insufficient exposure to sunlight or an insufficient intake of vitamin D-containing foods (e.g., egg yolks, liver, oily fish, cod liver oil, and “fortified” foods like some breakfast cereals and milk), consult your doctor for a blood test and subsequent supplementation decisions can be made with their advice. Self-diagnosis is never wise and mega-dosing with supplements is not recommended. As with any dietary supplement, “taking more does not equal a bigger effect” and a dietary supplement is intended as a supplement to, not a replacement for, real food — learn how to establish a healthy eating pattern at veohtu.com/healthyeatingpattern.
The effect sizesAn effect size is a standardized measure of the magnitude of an effect of an intervention. Unlike p-values, effect sizes show how large the effect is and indicate how meaningful it might be. Common effect size measures include standardised mean difference (SMD), Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients. are small for benefits to muscle strength, and the effects appear to be similar between males and females, although further research is needed in females because they are underrepresented among studies in this field.
Keep in mind: there is moderate-to-high heterogeneityHeterogeneity shows how much the results in different studies in a meta-analysis vary from each other. It is measured as the percentage of variation (the I2 value). A rule of thumb: if I2 is roughly 25%, that indicates low heterogeneity (good), 50% is moderate, and 75% indicates high heterogeneity (bad). High heterogeneity means there’s more variability in effects between studies and, therefore, a less precise overall effect estimate. (variability) in study designs and effect sizes between studies, the studies are generally small, and there is a moderate risk of biasRisk of bias in a meta-analysis refers to the potential for systematic errors in the studies included in the analysis. Such errors can lead to misleading/invalid results, and unreliable conclusions. This can arise because of issues with the way participants are selected (randomisation), how data is collected and analysed, and how the results are reported. and possible publication biasPublication bias in meta-analysis occurs when studies with significant results are more likely to be published than those with non-significant findings, leading to distorted conclusions. This bias can inflate effect sizes and misrepresent the true effectiveness of interventions, making it crucial to identify and correct for it in research.. So, the overall certainty of evidenceCertainty of evidence tells us how confident we are that the results reflect the true effect. It’s based on factors like study design, risk of bias, consistency, directness, and precision. Low certainty means more doubt and less confidence, and that future studies could easily change the conclusions. High certainty means that the current evidence is so strong and consistent that future studies are unlikely to change conclusions. is lowA low quality of evidence means that, in general, studies in this field have several limitations. This could be due to inconsistency in effects between studies, a large range of effect sizes between studies, and/or a high risk of bias (caused by inappropriate controls, a small number of studies, small numbers of participants, poor/absent randomisation processes, missing data, inappropriate methods/statistics). When the quality of evidence is low, there is more doubt and less confidence in the overall effect of an intervention, and new studies could easily change overall conclusions. The most effective way to enhance the quality of evidence is for scientists to conduct large, well-controlled, high-quality randomised controlled trials.. Therefore, additional high-quality randomised controlled trialsThe “gold standard” approach for determining whether a treatment has a causal effect on an outcome of interest. In such a study, a sample of people representing the population of interest is randomised to receive the treatment or a no-treatment placebo (control), and the outcome of interest is measured before and after exposure to the treatment and control. are needed to increase the certainty (confidence) in the overall effect sizes reported in meta-analysesA meta-analysis quantifies the overall effect size of a treatment by compiling effect sizes from all known studies of that treatment..
To minimise the risk of consuming a supplement that contains prohibited substances, only choose products that have been independently tested (e.g., Informed Sport). And, remember: Supplements do not make athletes and do not replace training; they're just the icing on a very well-baked cake. Before reaching for pills and potions, optimise your training load and dial in your sleep, nutrition, and rest.
The information I provide is not medical advice. Vitamin D can have side effects and might interact with other drugs, nutrients, and medical conditions (see here). If you are unsure, always consult your doctor to ensure that a specific supplement is safe for you to use.
Full list of meta-analyses examining vitamin D for performance.
Here are the meta-analyses I've summarised above:
Effects of vitamin D supplementation on maximal strength and power in athletes: a systematic review and meta-analysis of randomized controlled trials. Sist et al. (2023) Front Nutr
Effects of vitamin D supplementation on muscle function and recovery after exercise-induced muscle damage: A systematic review. Rojano-Ortega et al. (2023) J Hum Nutr Diet
Vitamin D Supplementation Improves Handgrip Strength in Postmenopausal Women: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Jia-Li Zhang, Christina Chui-Wa Poon, Man-Sau Wong, Wen-Xiong Li, Yi-Xun Guo, Yan Zhang. Front Endocrinol (2022)
Effect of vitamin D monotherapy on indices of sarcopenia in community-dwelling older adults: a systematic review and meta-analysis. Konstantinos Prokopidis, Panagiotis Giannos, Konstantinos Katsikas Triantafyllidis, Konstantinos S Kechagias, Jakub Mesinovic, Oliver C Witard, David Scott. J Cachexia Sarcopenia Muscle (2022)
Effects of Vitamin D in Post-Exercise Muscle Recovery. A Systematic Review and Meta-Analysis. Hugo J Bello, Alberto Caballero-García, Daniel Pérez-Valdecantos, Enrique Roche, David C Noriega, Alfredo Córdova-Martínez. Nutrients (2021)
The Optimal Strategy of Vitamin D for Sarcopenia: A Network Meta-Analysis of Randomized Controlled Trials. Shih-Hao Cheng, Kee-Hsin Chen, Chiehfeng Chen, Woei-Chyn Chu, Yi-No Kang. Nutrients (2021)
The effects of vitamin D supplementation on muscle strength and mobility in postmenopausal women: a systematic review and meta-analysis of randomised controlled trials. M Abshirini, H Mozaffari, H Kord-Varkaneh, M Omidian, M C Kruger. J Hum Nutr Diet (2020)
Effect of vitamin D supplementation on upper and lower limb muscle strength and muscle power in athletes: A meta-analysis. Lin Zhang, Minghui Quan, Zhen-Bo Cao. PLoS One (2019)
The effect of combined resistance exercise training and vitamin D3 supplementation on musculoskeletal health and function in older adults: a systematic review and meta-analysis. Antoniak AE, Greig CA. BMJ Open (2017)
Vitamin D supplementation and its influence on muscle strength and mobility in community-dwelling older persons: a systematic review and meta-analysis. H Rosendahl-Riise, U Spielau, A H Ranhoff, O A Gudbrandsen, J Dierkes. J Hum Nutr Diet (2017) — This article has a correction at ncbi.nlm.nih.gov/pmc/articles/PMC6885933/.
Effects of Vitamin D Supplementation on Serum 25-Hydroxyvitamin D Concentrations and Physical Performance in Athletes: A Systematic Review and Meta-analysis of Randomized Controlled Trials. Forough Farrokhyar, Gayathri Sivakumar, Katey Savage, Alex Koziarz, Sahab Jamshidi, Olufemi R Ayeni, Devin Peterson, Mohit Bhandari. Sports Med (2017)
Effects of Vitamin D Supplementation on Muscle Strength in Athletes: A Systematic Review. Chien-Ming Chiang, Ahmed Ismaeel, Rachel B Griffis, Suzy Weems. J Strength Cond Res (2017)
A Systematic Review of the Role of Vitamin D on Neuromuscular Remodelling Following Exercise and Injury. Minshull C, Biant LC, Ralston SH, Gleeson N. Calcif Tissue Int (2016)
Effects of vitamin D supplementation on upper and lower body muscle strength levels in healthy individuals. A systematic review with meta-analysis. Peter B Tomlinson, Corey Joseph, Manuela Angioi. J Sci Med Sport (2015)
The effects of vitamin D on skeletal muscle strength, muscle mass, and muscle power: a systematic review and meta-analysis of randomized controlled trials. Charlotte Beaudart, Fanny Buckinx, Véronique Rabenda, Sophie Gillain, Etienne Cavalier, Justine Slomian, Jean Petermans, Jean-Yves Reginster, Olivier Bruyère. J Clin Endocrinol Metab (2014)
Effect of vitamin D supplementation on muscle strength, gait and balance in older adults: a systematic review and meta-analysis. Muir SW, Montero-Odasso M. J Am Geriatr Soc (2011)
Effect of vitamin D supplementation on muscle strength: a systematic review and meta-analysis. K A Stockton, K Mengersen, J D Paratz, D Kandiah, K L Bennell. Osteoporos Int (2011)
Vitamin D-related changes in physical performance: a systematic review. C Annweiler, A M Schott, G Berrut, B Fantino, O Beauchet. Journal (2009)
Vitamin D and cognitive performance in adults: a systematic review. C Annweiler, G Allali, P Allain, S Bridenbaugh, A-M Schott, R W Kressig, O Beauchet. Eur J Neurol (2009)
Effects of vitamin D supplementation on strength, physical performance, and falls in older persons: a systematic review. Nancy K. Latham, Craig S. Anderson, Ian R. Reid. J Am Geriatr Soc (2003)
Consult WADA’s prohibited list.
Cross-check your meds against the Global DRO drug reference list.
Only choose supplements that have been independently tested by Informed Sport or LabDoor. You are the only person responsible for what goes in your body. Ignorance is not an excuse! Stay educated. Be informed.
Nail your daily nutrition habits first, layer specific sports nutrition on top of that, and then start to consider supplements.
What is the placebo effect?
In the 90s, I moshed my socks off to Brian Molko’s melodic voice at many a Placebo gig. He taught me one thing: placebos rock! Dad jokes aside, a placebo is sometimes used in clinical trials and usually takes the form of a sugar pill, a saline (salt water) injection (like saline), or sham (fake) surgery (where the surgeon opens you up, has some lunch, stitches you back up, and pretends they did a procedure on you). Theoretically, a placebo is supposed to have no effect on whatever variable of interest you are studying.
In a randomised controlled trial, there is a treatment group and a control group. Sometimes, the control group is given something that resembles the treatment to prevent participants from knowing which group they are in — this something is called a “placebo” and we’d call this type of trial a placebo-controlled clinical trial. If the variable of interest improves in the placebo-controlled group we might think that the placebo has had an effect. But, to make that conclusion, we would need an additional non-placebo control group to know whether the placebo has improved the variable of interest more than doing nothing at all — it could be that the disease naturally improves with time. When studies have a placebo-controlled group and a non-placebo control group, if the change in the variable of interest in the placebo group is larger than the change in the non-placebo group, we can conclude that there has been a placebo effect (and Brian Molko can sing about it). On the flip side, if the variable of interest worsens in the placebo-controlled group (and more so than in the non-placebo group), we conclude that there has been a nocebo effect (i.e. a negative or detrimental placebo effect).
Imagine this scenario:
You have an important race today and your coach gives you a supplement to take that they know is not proven to enhance performance. You don’t know what it is or what its effect is supposed to be but, because you want to win and you trust your coach, you take it. During the race, you feel like a monster — strong, fast, and highly motivated. You win! In your post-mortem of the race, you think, without a doubt, that the supplement made you win. Your mother says it was a coincidence. Your coach says you had trained for months, had been setting PBs, and were well-prepared and ready for a great race — you were always going to win.
Who is right… You? Your mother (who is usually right)? Or your coach?
If you are right, then this supplement could be called a placebo and your race win could be called a placebo effect. But, because you had a positive expectation of a performance-enhancing effect, the effect of the placebo could also be called a belief effect. But, a positive expectation of an effect is not always required for a placebo effect and having a positive expectation of an effect can even enhance the placebo effect. The important thing to learn is that while your experiences shape your beliefs, your experiences (i.e. you won after taking a supplement) must be combined with data (your training had been great, you’d set PBs all season, and were in the shape of your life) to accurately inform your belief. The other important thing to learn is that “you are the only person responsible for what goes in your body” — never take candy from a stranger your coach without knowing what it is, what it does, and whether it has been independently tested.
Now, that was just hypothetical — you’re probably wondering, does the placebo effect exist?
Several systematic reviews have found evidence for the placebo effect in a range of diseases in studies where participants are blinded to whether they are receiving a placebo or the real treatment. A couple of recent systematic reviews (see here & here) also find evidence for the placebo effect on a range of diseases when an “open-label” placebo (participants know they’re receiving a placebo) is compared to a non-placebo (no treatment) intervention, with summary effect sizesAn effect size is a quantitative measure of the magnitude of a relationship or difference between groups in a study. Unlike p-values, effect sizes show how large or meaningful that effect is. Common effect size measures include Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients. of 0.88 (a large effect; 95% confidence interval (CI)A measure of uncertainty used in Frequentist statistics. The 95% confidence interval is a plausible range of values within which the true value (e.g., the true treatment effect) would be found 95% of the time if the data was repeatedly collected in different samples of people. If this range of values (the confidence interval) crosses zero, there is little confidence in the effect. 0.62 to 1.14) and 0.72 (a moderate effect; 95%CI 0.39 to 1.05).
Woah!
But… These findings should be interpreted with caution because, in longitudinal studies (when the variable of interest is measured before and after several days/weeks/months/years), as I said earlier, the disease might naturally improve with time without real treatment. (Putting that in the context of exercise, your performance might improve while training with a supplement but it might also improve with training alone.) Furthermore, most studies do not have non-placebo control group. Plus, there are only a few small “open label” trials and participants weren’t blinded to the placebo vs. no treatment groups and, in many cases, participants received “positive messages” in addition to the open-label placebos before being asked about their feelings of pain or discomfort. E.g. “This will make you feel better.” ... … “How are you feeling?”.
Sometimes doctors prescribe placebos (without the patient’s knowledge) instead of therapeutic drugs to help “treat” a condition. As is probably obvious, from an ethical stance, placebos are a touchy subject — patients have a right to know what they’re receiving rather than being “deceived”. Furthermore, since the “belief effect” (the extent to which a person believes the treatment will work) can also influence the effectiveness of interventions, it could be argued that instead of deceptively-prescribing placebos (in place of therapeutic drugs), doctors could use the placebo effect and/or the belief effect to enhance the therapeutic effect of a drug — if a patient believes the treatment will help them, perhaps they’ll be more motivated to adhere to it. But, I’m going a little off-piste and away from exercise performance.
In research, it is very difficult for scientists to get “deception” studies approved by ethical review boards. But there are some fun examples. In a 2015 study from Ramzy et al., trained 10 km runners received no treatment or daily injections of “OxyRBX”, which they were told had the same effects as EPO (a red blood cell-boosting hormone that improves endurance performance). Before and after 7-days of treatment/no treatment, runners completed a 3 km race. On average, athletes in the OxyRBX group improved their 3 km time by 9.73 seconds (95% CIA measure of uncertainty used in Frequentist statistics. The 95% confidence interval is a plausible range of values within which the true value (e.g., the true treatment effect) would be found 95% of the time if the data was repeatedly collected in different samples of people. If this range of values (the confidence interval) crosses zero, there is little confidence in the effect. 5.14 to 14.33 seconds) whereas untreated athletes ran 1.82 s faster (95%CI 2.77 s slower to 6.41 s faster; group-change comparison P=0.02A p-value is a statistical measure that indicates the probability that the result is at least as extreme than that observed if the null-hypothesis was true. If P is small, the observed difference is big enough to disprove (reject) the null hypothesis. In very basic terms, P = probability that the effect could be explained by random chance and a P-value of less than 0.05 means the results look so promising that there’s only a 1-in-20 (or 5%) chance that they would have occurred if the treatment had no effect at all. Common thresholds for significance are 0.05, 0.01, and 0.001.). OxyRBX-treated runners also reported less physical effort, increased motivation, and improved recovery. This is an example of a placebo effect, probably caused by a belief effect.
That’s kinda fun but now consider this thought experiment:
A study tests the hypothesis that a caffeine-containing beverage improves 3 km running performance in well-trained runners. The runners complete the 3 km time trial four times in a randomised cross-over design, at the same time of day following a 5-day period of identical nutrition, sleep, and training. In each trial, runners are given 250 mL of cold fluid to ingest 30-mins prior to the time trial — the fluid is either water (no treatment), coffee (treatment), decaf coffee (placebo 1), and the same type of decaf coffee (placebo 2). The runners do not see the drinks being prepared and cannot see the drinks until they sip from them, but they obviously taste that water is not coffee. However, they cannot taste the difference between the coffee and the decaf. But, in one of the decaf coffee trials, runners are told that “This coffee has a lot of caffeine and will massively improve your performance today.” — this is the “belief” trial. When the study is finished and analysed, the data show that 3 km performance was equally faster in the coffee and the “belief” decaf trials than in the water and decaf trials, which were not different from one another. The researchers conclude that there was no placebo effect of decaf placebo 1 but there was a placebo effect (or belief effect) of decaf placebo 2 — decaf coffee gave the same performance-enhancing boost as coffee when runners were told it would.
As you can see, the placebo effect is complicated yet has potential in the athletic arena. But, does it actually work? The obvious question to ask is…
What is the scientific evidence on the placebo effect’s impact on athletic performance?
The placebo (or nocebo) effect is a difficult thing to assess. The placebo must be indistinguishable from the actual treatment, a non-placebo control group must also be included, studies must control for participants’ knowledge of the effect of the treatment and/or placebo, and studies must control for the participant correctly guessing whether they have received treatment or not. These things are not always possible and are sometimes impossible (e.g. you cannot blind a person from doing a type of exercise; similarly, you can’t blind someone from being in a sauna).
In studies with a placebo control and a non-placebo control, the placebo effect explains ~50% of the beneficial effect of exercise training on cognitive function and psychological outcomes inc. anxiety, depression, mood, etc (Lindheimer et al. 2015: placebo effect sizeAn effect size is a quantitative measure of the magnitude of a relationship or difference between groups in a study. Unlike p-values, effect sizes show how large or meaningful that effect is. Common effect size measures include Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients. = 0.20, 95% CIA measure of uncertainty used in Frequentist statistics. The 95% confidence interval is a plausible range of values within which the true value (e.g., the true treatment effect) would be found 95% of the time if the data were repeatedly collected in different samples of people. If this range of values (the confidence interval) crosses zero, there is little confidence in the effect. -0.02 to 0.41; exercise effect size = 0.37, 95%CI 0.11 to 0.63). But, more high-quality randomised controlled trials are needed to bolster these findings and none of these studies was on athletes.
When pooling several nutritional (inc. caffeine, beta-alanine, sodium bicarbonate, and anabolic steroids) and mechanical (inc. electrical muscle stimulation, kinesiology tape, blood flow restriction, magnetic bands, and cold water immersion) interventions in “deception” studies where participants are led to believe they’re receiving a beneficial treatment, there are small to moderate placebo effects (effect sizeAn effect size is a quantitative measure of the magnitude of a relationship or difference between groups in a study. Unlike p-values, effect sizes show how large or meaningful that effect is. Common effect size measures include Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients. = 0.36) and nocebo effects (effect size = 0.37) on sports performance. But, the methodological quality of the studies is generally poor so more high-quality randomised controlled trials are needed.
When specifically assessing caffeine and buffering supplements (e.g. sodium bicarbonate) in blinded studies where participants don’t know if they’re on placebo or treatment, the placebo has a trivial (tiny) but meaningful (the 95% CIA measure of uncertainty used in Frequentist statistics. The 95% confidence interval is a plausible range of values within which the true value (e.g., the true treatment effect) would be found 95% of the time if the data were repeatedly collected in different samples of people. If this range of values (the confidence interval) crosses zero, there is little confidence in the effect. does not cross zero) effect on (effect sizeAn effect size is a quantitative measure of the magnitude of a relationship or difference between groups in a study. Unlike p-values, effect sizes show how large or meaningful that effect is. Common effect size measures include Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients. = 0.09, 95%CI 0.01 to 0.17) vs. the non-placebo-control while the actual treatment has a small effect (effect size = 0.37, 95%CI 0.20 to 0.56) vs. no treatment on running and cycling time-to-exhaustion and time-trial performance. This means that ~25% of the performance-enhancing effect of caffeine or buffers is explained by a placebo effect.
Therefore…
Since placebo effects are real and have a small effect, it would be prudent for an athlete (and an athlete’s support team) to try to maximise the placebo effect of a proven treatment by encouraging belief in its effectiveness.
If you choose to use the placebo effect, a reasonable approach is to:
Instil belief in the approaches you use and in the people you work with. Note: this is based on effective doses used in research.
But be aware that psychological belief in an approach can be a replacement for science EXCEPT when science shows that the approach has detrimental physiological effects. For example, many athletes claim that they “recover better” when using ice baths (cold water immersion) after exercise. But, while cold water immersion may reduce feelings of soreness and improve feelings of recovery in the short-term, in the long-term, daily post-exercise cold water immersion has been shown to blunt training adaptations.
Can the placebo effect enhance athletic recovery and performance?
Using the placebo effect is likely to improve performance, but unlikely to improve recovery. On the flipside, the nocebo effect (negative expectations) is likely to impair performance.
The effect sizeAn effect size is a standardized measure of the magnitude of an effect of an intervention. Unlike p-values, effect sizes show how large the effect is and indicate how meaningful it might be. Common effect size measures include standardised mean difference (SMD), Cohen’s d, Hedges’ g, eta-squared, and correlation coefficients. for improving performance is small.
Due to insufficient research, it is unclear whether the effect is similar between trained athletes and untrained folks, or between males and females.
Keep in mind: the studies are small and few in number, and there is high heterogeneityHeterogeneity shows how much the results in different studies in a meta-analysis vary from each other. It is measured as the percentage of variation (the I2 value). A rule of thumb: if I2 is roughly 25%, that indicates low heterogeneity (good), 50% is moderate, and 75% indicates high heterogeneity (bad). High heterogeneity means there’s more variability in effects between studies and, therefore, a less precise overall effect estimate. (variability) in effects between studies with a high risk of biasRisk of bias in a meta-analysis refers to the potential for systematic errors in the studies included in the analysis. Such errors can lead to misleading/invalid results, and unreliable conclusions. This can arise because of issues with the way participants are selected (randomisation), how data is collected and analysed, and how the results are reported.. So, the overall certainty of evidenceCertainty of evidence tells us how confident we are that the results reflect the true effect. It’s based on factors like study design, risk of bias, consistency, directness, and precision. Low certainty means more doubt and less confidence, and that future studies could easily change the conclusions. High certainty means that the current evidence is so strong and consistent that future studies are unlikely to change conclusions. is lowA low quality of evidence means that, in general, studies in this field have several limitations. This could be due to inconsistency in effects between studies, a large range of effect sizes between studies, and/or a high risk of bias (caused by inappropriate controls, a small number of studies, small numbers of participants, poor/absent randomisation processes, missing data, inappropriate methods/statistics). When the quality of evidence is low, there is more doubt and less confidence in the overall effect of an intervention, and new studies could easily change overall conclusions. The most effective way to enhance the quality of evidence is for scientists to conduct large, well-controlled, high-quality randomised controlled trials.. Therefore, additional high-quality randomised controlled trialsThe “gold standard” approach for determining whether a treatment has a causal effect on an outcome of interest. In such a study, a sample of people representing the population of interest is randomised to receive the treatment or a no-treatment placebo (control), and the outcome of interest is measured before and after exposure to the treatment and control. are needed to increase the certainty (confidence) in the overall effect size of the placebo effect.
The nice part: the placebo effect doesn't appear to hurt recovery or performance. So, if you like using it and believe it works for you, give it a whirl.
But, remember that the placebo effect does not make an athlete — the placebo effect does not replace training and placebo effects are not additive. I.e., using and believing in 5 supplements that don’t have proven ergogenic effects won't give you 5-times the benefit. Instead, it will give you 5 more factors that cost money and time and could return a positive doping test. This creates stress, and stress is the antithesis of the recovery and adaptation required for high performance. Yes, the placebo effect is real but, before playing with magic, first invest your valuable time and money in the things that will guarantee high performance: Optimise your training load, and nail your sleep, nutrition, and rest. No tricks. Just learn to understand yourself, watch for patterns, and intervene.
Full list of meta-analyses examining the placebo effect for recovery and performance.
Here are the meta-analyses I've summarised above:
Placebo and Nocebo Effects in Motor Performance: An Overview of Reviews. Brietzke et al. Brain Behav (2025)
Negative expectations and measurable movement mechanics: a scoping review of the nocebo effect on motor performance. Burgos-Tirado et al. Front Hum Neurosci (2025)
Caffeine Placebo Effect in Sport and Exercise: A Systematic Review. Vega-Muñozet al. (2024) Nutrients.
Placebo and Nocebo Effects on Sports and Exercise Performance: A Systematic Literature Review Update. Chhabra et al. Nutrients. (2024)
Nonplacebo Controls to Determine the Magnitude of Ergogenic Interventions: A Systematic Review and Meta-analysis. Felipe Miguel Marticorena, Arthur Carvalho, Luana Farias DE Oliveira, Eimear Dolan, Bruno Gualano, Paul Swinton, Bryan Saunders. Med Sci Sports Exerc (2021)
The Placebo and Nocebo effect on sports performance: A systematic review. Philip Hurst, Lieke Schipof-Godart, Attila Szabo, John Raglin, Florentina Hettinga, Bart Roelands, Andrew Lane, Abby Foad, Damian Coleman, Chris Beedie. Eur J Sports Sci (2020)
Consensus statement on placebo effects in sports and exercise: The need for conceptual clarity, methodological rigour, and the elucidation of neurobiological mechanisms. Beedie et al. (2018) Eur J Sport Sci
Quantifying the placebo effect in psychological outcomes of exercise training: a meta-analysis of randomized trials. Jacob B Lindheimer, Patrick J O'Connor, Rod K Dishman. Sports Med (2015)
Consult WADA’s prohibited list.
Cross-check your meds against the Global DRO drug reference list.
Only choose supplements that have been independently tested by Informed Sport or LabDoor. You are the only person responsible for what goes in your body. Ignorance is not an excuse! Stay educated. Be informed.
Nail your daily nutrition habits first, layer specific sports nutrition on top of that, and then start to consider supplements.Position stands and consensus statements are written by a panel of experts (typically more than 10) chosen by the issuing society to grade the quality of evidence on a particular topic. A position stand is a detailed policy recommendation published by a society that describes a course of action for practice. A consensus statement is a collective opinion of a society’s opinion that is used to develop evidence-based guidelines.
These types of documents are typically peer-reviewed by several folks and go through several revisions before being published. Unlike experimental studies, a position stands and consensus statements represent an opinion, but a good position/consensus document will use evidence from high-quality, large-scale, randomised controlled trials and, ideally, systematic reviews and meta-analyses, and then discuss the evidence in the context of practice.
Several sports supplement-related position stands and consensus statements have been published by reputable societies and governing bodies, such as the American College of Sports Medicine (ACSM), the International Olympic Committee (IOC), and the International Society for Sports Nutrition (ISSN):
⸰ ACSM — Nutrition and Athletic Performance position statement. Travis Thomas, Kelly Erdman, & Louise Burke. Med Sci Sports Exerc (2016)
⸰ IOC — Consensus statement: dietary supplements and the high-performance athlete. Ron Maughan and colleagues. Br J SportsMed (2018)
⸰ ISSN — Exercise & sports nutrition position statement. Chad Kerksick and colleagues. J Int Soc Sports Nutr (2018). The ISSN have also published individual position statements on the use of caffeine, creatine, beta-alanine, and HMB (β-hydroxy β-methylbutyrate).
Which supplements do the sports nutrition guidelines say have a beneficial effect on performance?
ACSM says that creatine (for very short-duration high-intensity efforts), caffeine (to reduce perception of fatigue and maintain power for longer), sodium bicarbonate (for short-duration high-intensity efforts), beta-alanine (for short-duration high-intensity efforts), and nitrate (for medium-duration endurance performance) are likely to have a beneficial effect on performance.
ISSN says that HMB, creatine monohydrate, essential amino acids (EAA), and protein are likely to be beneficial for muscle building, and that beta-alanine, caffeine, creatine monohydrate, sodium bicarbonate, and sodium phosphate are likely to be beneficial for performance.
IOC says that creatine, caffeine, sodium bicarbonate, beta-alanine, and nitrate are likely to be beneficial to performance (a veritable replica of ACSM’s guidelines). The IOC also published a flow chart (see Figures 2 and 3 in the IOC consensus statement) to help inform decisions about using sports supplements while reducing the risk of an anti-doping rule violation.
With that knowledge, always remember that supplements do not make athletes and do not replace training; they're just the icing on a very well-baked cake. Before reaching for pills and potions, optimise your training load and dial in your sleep, nutrition, and rest.
Consult WADA’s prohibited list.
Cross-check your meds against the Global DRO drug reference list.
Only choose supplements that have been independently tested by Informed Sport or LabDoor. You are the only person responsible for what goes in your body. Ignorance is not an excuse! Stay educated. Be informed.
Nail your daily nutrition habits first, layer specific sports nutrition on top of that, and then start to consider supplements.Disclaimer I occasionally mention brands and products, but it is important to know that I don't sell recovery products, supplements, or ad space, and I'm not affiliated with / sponsored by / an ambassador for / receiving advertisement royalties from any brands. I have conducted biomedical research for which I’ve received research money from publicly-funded national research councils and medical charities, and also from private companies, including Novo Nordisk Foundation, AstraZeneca, Amylin, the A.P. Møller Foundation, and the Augustinus Foundation. I’ve also consulted for Boost Treadmills and Gu Energy on R&D grant applications, and I provide research and scientific writing services for Examine.com. Some of my articles contain links to information provided by Examine.com but I do not receive any royalties or bonuses from those links. Importantly, none of the companies described above have had any control over the research design, data analysis, or publication outcomes of my work. I research and write my content using state-of-the-art, consensus, peer reviewed, and published scientific evidence combined with my empirical evidence observed in practice and feedback from athletes. My advice is, and always will be, based on my own views and opinions shaped by the scientific evidence available. The information I provide is not medical advice. Before making any changes to your habits of daily living based on any information I provide, always ensure it is safe for you to do so and consult your doctor if you are unsure.