What are the best supplements for runners, OCR athletes, and endurance training?
The Sports Supplements Tool from Thomas Solomon, PhD.
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 any 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.
Click the supplement you want to read about:
Share this tool with your people:Strengthen the fight for clean sport
Remember: You are the only person responsible for what goes in your body! Ignorance is not an excuse! Stay educated. Be informed.
Consult WADA’s prohibited list, cross-check your meds against the Global DRO drug reference list, and only choose supplements that have been tested by an independent body (e.g., Informed Sport or LabDoor).
Who is Thomas Solomon?
My knowledge has been honed following 20+ years of running, cycling, hiking, cross-country skiing, lifting, and climbing, 15+ years of academic research at world-leading universities and hospitals, and 10+ years advising and coaching in athletic performance and lifestyle change.
I have a BSc in Biochemistry, a PhD in Exercise Science, and over 90 peer-reviewed publications in medical journals.
I'm also an ACSM-certified Exercise Physiologist (ACSM-EP), an ACSM-certified Personal Trainer (ACSM-CPT), a VDOT-certified Distance Running Coach, and a UKVRN Registered Nutritionist (RNutr).
Since 2002, I’ve conducted biomedical research in exercise and nutrition and have taught and led university courses in exercise physiology, nutrition, biochemistry, and molecular medicine.
And, with my personal experience of competing on the track (800m to 10,000m), the road (5 k to marathon), on the trails, and in the mountains, by foot, bicycle, cross-country ski, and during obstacle course races (OCR), I deeply understand what it's like to train and compete — I've been there, done it, and gotten sweat, mud, and tears on my t-shirt.
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.
