How HMB affects performance and recovery for running, OCR, and endurance sports
Thomas Solomon, PhD.
Updated onReading time approx 7 minutes (1400 words).
What you’ll learn:
HMB is a small molecule your body makes from the amino acid leucine; it helps turn on muscle building and turn down muscle breakdown at the same time.
If you’re new to strength training, daily HMB might nudge strength gains up a bit.
But, if you’re already well-trained, HMB probably won’t add extra muscle or strength beyond good training and enough protein.
For endurance performance, results are mixed and studies aren’t strong enough yet to call it a clear win.
Curious about the how and why? Scroll down for the details, the nuances, and the nerdy bits.
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 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..
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).
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.
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)
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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.