Protocols by Charles Sieg

Supplements

HMB

What the research says about beta-hydroxy-beta-methylbutyrate for muscle, recovery, and aging, where the big claims came from, and what happens when you stack it with creatine.

Overall evidence Mixed19 sourcesReviewed November 5, 2026

A society position stand written partly by HMB patent holders and a meta-analysis in untrained men support some benefit, but pooled trials in trained athletes and in older adults on resistance training find little or none, and the biggest single result comes from a trial that drew a published challenge.

The short version

  • I take HMB from Optimum Nutrition. HMB (beta-hydroxy-beta-methylbutyrate) is a metabolite of the amino acid leucine that the body makes on its own1.
  • The International Society of Sports Nutrition (ISSN) says 38 mg per kilogram of body weight a day, with exercise training, may improve body composition, and that HMB may improve strength and power in untrained people while results in trained athletes are mixed. The 2025 stand's lead author is a named inventor on active HMB patents1.
  • Other meta-analyses are less kind. In trained athletes HMB had trivial, non-significant effects on strength and body composition, and in adults 50 and older on resistance-training programs it added no measurable advantage2,3.
  • The most dramatic published gains came from a 2014 trial funded in part by a company that marketed HMB. A 2017 letter questioned its data along with two other papers from the same study, and the lead author replied that there were no discrepancies4,1,5,6.
  • With creatine, the evidence is thin and mixed: the authors of a 2001 trial called the two additive, and a 2020 trial in rugby players found no extra benefit from adding HMB7,8.

The protocol

This is what the research and the label say, not a prescription. I have not listed my own dose or timing here.

ParameterWhat the sources say
Daily dose in the ISSN stands38 mg per kilogram of body weight a day, with exercise training1,9
The usual dose in trials3 g a day10,7
FormsCalcium HMB and HMB free acid. The 2025 stand says the free acid raises blood HMB more than the calcium form, though recent results are mixed1
TimingThe 2025 stand says taking it close to exercise may help muscle protein synthesis and dampen inflammation1
DurationThe 2025 stand says the performance benefits in trained athletes grow in studies longer than 6 weeks, and a meta-analysis found the effect on muscle-damage markers significant in studies over 6 weeks1,11
Optimum Nutrition's labelAs of November 2026, the maker's page for its HMB capsules says a serving is 3 capsules with 3 g of calcium HMB, lists 30 servings (90 capsules) per container, and directs 3 capsules daily12

The same page also says "Every capsule contains 3g of pure HMB," which conflicts with 3 g per 3-capsule serving; I go by the serving figure, which the page repeats in its product details. I found no third-party certification named on the page12. Optimum Nutrition sells these capsules and its creatine gummies as separate products12,13.

Why it works

The ISSN says HMB mainly works by increasing muscle protein synthesis and reducing muscle protein breakdown, and that it may reduce muscle damage and promote muscle recovery1. Those are the society's conclusions from its review of the literature, and several of the authors have financial ties to HMB. The stand's own disclosures say the lead author works for MTI Biotech, previously worked at Metabolic Technologies, Inc., which until recently marketed both forms of HMB, and is a named inventor on active HMB patents; the second author consults for MTI Biotech and is also a named inventor; and the ISSN has at times received grant support from companies that sell, market, or manufacture HMB1. That doesn't make the conclusions wrong, but it's why I weigh the pooled trial data below more heavily.

What the research says

Moderate Untrained young men, strength. A meta-analysis of nine studies (14 comparisons, 394 subjects, average age 23) found small strength benefits in untrained lifters: 9.9 percent for lower-body strength and 6.6 percent for average strength, with negligible upper-body gains (2.1 percent). In trained lifters every strength effect was trivial, and effects on fat and fat-free mass were trivial. The interventions averaged about 5 weeks14. The ISSN's 2025 stand says HMB may improve strength and power in untrained people1.

Moderate Trained athletes: little or nothing. A meta-analysis of six randomized trials with 193 trained and competitive athletes found trivial, non-significant effect sizes for every outcome (bench press 0.00, leg press 0.09, body mass -0.01, fat-free mass 0.16, and fat mass -0.20), and the result held across HMB dose, duration, training level, and diet2. The earlier meta-analysis also found strength effects trivial in trained men14. The ISSN's own word for performance results in trained athletes is "mixed"1.

Moderate Muscle damage markers. A meta-analysis of randomized trials found HMB lowered creatine kinase across 10 studies (324 participants; weighted mean difference -60.71 U/L, 95% CI -78.12 to -43.29) and lactate dehydrogenase across 8 studies (229 participants; -15.42 U/L, 95% CI -22.2 to -8.6), and a subgroup analysis found the effect significant in studies over 6 weeks11. Those are blood markers of damage, not soreness or performance.

Mixed Older adults. A 2015 meta-analysis of seven randomized trials (147 on HMB, 140 controls) in people aged 65 and older found greater muscle mass gain with HMB (SMD 0.352, 95% CI 0.11 to 0.594, P = 0.004) and no significant change in fat mass15. A 2026 meta-analysis of 13 randomized trials (561 people aged 50 and older) that all paired HMB with resistance training found no advantage for HMB on muscle mass (SMD 0.05, 95% CI -0.10 to 0.20), strength (SMD 0.04, 95% CI -0.72 to 0.63), or fat mass (SMD 0.24, 95% CI -0.01 to 0.49), and the authors do not recommend it as a routine adjunct for people who can do structured exercise3. A 2021 review found three recent studies in community-dwelling older adults, said their results were influenced by suboptimal methodological quality, and called for better trials16. The ISSN says HMB may help sedentary and older adults and may help treat age-related muscle loss (sarcopenia) under select conditions1. My read: the case is better for older people who aren't training than for those who already lift1,3.

The disputed 12-week trial

One trial supplies much of the excitement. A 2014 randomized, double-blind trial gave 24 resistance-trained men 3 g a day of HMB free acid or a placebo, with results reported for 20 (11 on HMB free acid, 9 on placebo). It reported total strength up 77.1 versus 25.3 kg, lean body mass up 7.4 versus 2.1 kg (p < 0.001), and a blunted creatine kinase rise during overreaching (-6 versus 277 IU/l)4. Those gains are far larger than anything in the pooled results for trained people above2. The study was funded in part by Metabolic Technologies, Inc., and three of its authors were employed there4; the 2025 ISSN stand says that company marketed both forms of HMB until recently1.

In 2017, Jeremy Gentles and Stuart Phillips published a letter about three papers from that one study (registered as NCT01508338), the 2014 trial among them. They pointed to supplement protocols that differ between the papers and from the trial registration, a shared placebo group whose size changes from paper to paper without explanation, and an "extraordinary level of homogeneity" in group means and standard deviations across the three papers. They declared no competing interests5. Jacob Wilson, the lead author, replied that the questions concerned the similarity of subject characteristics across the papers and the differing placebo group sizes, and that there are no discrepancies, only a misunderstanding of the papers6. No pooled analysis of trained athletes comes close to those gains2, so I treat the 2014 numbers as unconfirmed.

HMB with creatine

This is the "stack" question, and the evidence is small.

Early The first test. A 3-week double-blind trial of 40 people randomized to placebo, creatine, HMB, or both found the creatine and HMB groups gained 0.92 and 0.39 kg more lean body mass than placebo and the combined group 1.54 kg more, with no creatine-by-HMB interaction (P = 0.73), so the authors called the effects additive. Creatine's effect on lean mass was significant (P = 0.05); HMB's was a trend (P = 0.08). HMB blunted the exercise-induced rise in creatine kinase, but creatine counteracted that effect. Groups held 9 to 11 people, and lean mass was estimated by bioelectrical impedance7.

Early Rugby players. A 2020 double-blind crossover study recruited 16 male collegiate rugby players and compared HMB plus creatine (5 g of each daily) with creatine plus placebo for 6 weeks; 13 were retested after the first 6 weeks and 8 returned for the crossover. The authors concluded that adding HMB gave no greater benefit than creatine alone8.

Early The review. A systematic review of six articles found the strength, anaerobic, and body-composition results mixed and no benefit for muscle-damage or hormone markers, and concluded that 3 to 10 g a day of creatine plus 3 g a day of HMB for 1 to 6 weeks could benefit strength and anaerobic performance17.

Early Older adults. A 2026 randomized, double-blind, placebo-controlled crossover trial of 30 adults aged 60 or older found that creatine plus HMB, alongside four supervised exercise sessions a week for 6 weeks, improved several functional strength and endurance tests, largely independent of changes in muscle mass. It had no HMB-only or creatine-only arm, so it can't separate the two18.

The honest bottom line: no study here shows the combination clearly beats creatine alone, and creatine has the far stronger evidence by itself (see the creatine page).

Rhonda Patrick on HMB

Rhonda Patrick took a listener question on HMB in FoundMyFitness Q&A #36, a members-only episode posted June 4, 202219. In the transcript she says she didn't ask Stuart Phillips, whom she had just interviewed, about HMB. She runs through what helps preserve muscle, mostly as Phillips sees it (enough protein, omega-3, vitamin D, and creatine), says she doesn't know whether HMB adds anything on top of those, and adds that he "didn't really mention it as like a big thing"19. The episode lists no HMB studies for that question19. That is a spoken answer to one question, not a review, and her appearance here does not mean she endorses me or this site.

How I use it

I take HMB from Optimum Nutrition, along with creatine gummies (see the creatine page). That is all I have told the site so far.

Where I buy it

I don't list prices because they change. The links are plain product links, with no referral tag.

Cautions

  • Calcium HMB is the form on the Optimum Nutrition label12. The ISSN says chronic use of either form appears safe for at least one year and that neither harms glucose tolerance or insulin sensitivity1. That is a society statement from authors with ties to HMB, so I read it as "no red flags found," not "proven safe for everyone."
  • Safety in pregnancy, in kidney or liver disease, and with specific medications is not covered by anything I read for this page. That's a question for a doctor.
  • The effect in trained people is close to zero in the pooled data. For someone who already lifts hard, I would not expect much2,3.
  • The biggest effects come from a trial funded in part by a company that marketed HMB, and its data drew a published challenge4,1,5,6.
  • I found no third-party certification, such as Informed Choice or NSF Certified for Sport, named on Optimum Nutrition's HMB page, which matters for anyone in tested sport12.

References

  1. Rathmacher JA, Pitchford LM, Stout JR, Townsend JR, Jäger R, Kreider RB, et al. International society of sports nutrition position stand: β-hydroxy-β-methylbutyrate (HMB). Journal of the International Society of Sports Nutrition. 2025;22(1):2434734.Position standPubMed 39699070 · DOI

    What it found: The updated ISSN position stand lists 12 points. It says chronic use of either form is safe for at least one year, that 38 mg/kg body weight a day with exercise training may improve body composition, that HMB may improve strength and power in untrained people, that results in trained athletes are mixed and improve with studies longer than 6 weeks, and that HMB may help sedentary and older adults improve strength, function, and muscle quality.

    Limits: A society position stand that reviews the literature rather than testing HMB itself; its disclosures say the lead author works for MTI Biotech and, with two co-authors, is named as an inventor on HMB-related patents, and that the ISSN has at times received grants from companies that sell, market, or manufacture HMB.

  2. Sanchez-Martinez J, Santos-Lozano A, Garcia-Hermoso A, Sadarangani KP, Cristi-Montero C. Effects of beta-hydroxy-beta-methylbutyrate supplementation on strength and body composition in trained and competitive athletes: A meta-analysis of randomized controlled trials. Journal of Science and Medicine in Sport. 2018;21(7):727-735.Meta-analysisPubMed 29249685 · DOI

    What it found: Meta-analysis of six randomized trials with 193 trained and competitive athletes. HMB had trivial, non-significant effect sizes for every outcome: bench press 0.00, leg press 0.09, body mass -0.01, fat-free mass 0.16, and fat mass -0.20, and the authors concluded it had no effect on strength or body composition in these athletes.

    Limits: Only six small trials, and the abstract does not report confidence intervals.

  3. Wang G, Jawed I, Tufail M, Sharaf MS, Bin Gulzar AH, Qurat Ul Ain H, et al. Efficacy of HMB supplementation as an adjunct to resistance training in older adults: a comprehensive meta-analysis. Age and Ageing. 2026;55(3):afag073.Meta-analysisPubMed 41934514 · DOI

    What it found: Meta-analysis of 13 randomized trials with 561 adults aged 50 and older doing resistance training. HMB showed no clear advantage for fat mass (SMD 0.24, 95% CI -0.01 to 0.49), muscle mass (SMD 0.05, 95% CI -0.10 to 0.20), or muscle strength (SMD 0.04, 95% CI -0.72 to 0.63), and the authors do not recommend it as a routine adjunct for people who can do structured exercise.

    Limits: Strength results were highly heterogeneous, and the review covers people who already train, not people who cannot exercise.

  4. Wilson JM, Lowery RP, Joy JM, Andersen JC, Wilson SMC, Stout JR, et al. The effects of 12 weeks of beta-hydroxy-beta-methylbutyrate free acid supplementation on muscle mass, strength, and power in resistance-trained individuals: a randomized, double-blind, placebo-controlled study. European Journal of Applied Physiology. 2014;114(6):1217-1227.Randomized trialPubMed 24599749 · DOI

    What it found: Twelve-week randomized, double-blind trial of HMB free acid in resistance-trained people. The abstract reports total strength up 77.1 versus 25.3 kg, lean body mass up 7.4 versus 2.1 kg (p < 0.001), and a blunted rise in creatine kinase during overreaching (-6 versus 277 IU/l), all favoring HMB free acid.

    Limits: The abstract gives no sample size or dose (the full text reports 24 men and 3 g a day), the gains are far larger than the pooled results in trained people, the study was funded in part by Metabolic Technologies Inc., which employed three of its authors, and a 2017 letter names it as one of three papers from one study whose placebo groups and subject data it questioned.

  5. Gentles JA, Phillips SM. Discrepancies in publications related to HMB-FA and ATP supplementation. Nutrition & Metabolism, 2017.ArticlePubMed 28680453 · DOI

    What it found: A letter that says it addresses several discrepancies found across multiple publications on HMB free acid and ATP supplementation. The PubMed record states that the authors declare no competing interests.

    Limits: A letter, not a study; its full text names the three papers in question, all from one registered study, and the 2014 HMB free acid trial is one of them.

  6. Wilson JM. Response to discrepancies in publications related to HMB-FA and ATP supplementation. Nutrition & Metabolism, 2017.ArticlePubMed 29209404 · DOI

    What it found: The reply to the Gentles and Phillips letter. It addresses questions about whether subject characteristics were consistent across three papers on ATP, HMB, and their combination and why placebo group sizes differ, and argues the papers contain no discrepancies and that the questions come from a misunderstanding of the papers.

    Limits: The author's own reply to critics of his research group's work, and the PubMed record states he declares no competing interests.

  7. Jówko E, Ostaszewski P, Jank M, Sacharuk J, Zieniewicz A, Wilczak J, et al. Creatine and beta-hydroxy-beta-methylbutyrate (HMB) additively increase lean body mass and muscle strength during a weight-training program. Nutrition. 2001;17(7-8):558-566.Randomized trialPubMed 11448573 · DOI

    What it found: Three-week double-blind trial of 40 people randomized to placebo (n = 10), creatine (n = 11), HMB (n = 9), or creatine plus HMB (n = 10), with 3.0 g/day of HMB. Versus placebo the creatine, HMB, and combined groups gained 0.92, 0.39, and 1.54 kg more lean body mass; creatine had a main effect (P = 0.05), HMB a trend (P = 0.08), and there was no interaction (P = 0.73), so the authors called the effects additive.

    Limits: Three weeks, 9 to 11 people per group, and lean mass was estimated with bioelectrical impedance.

  8. Mangine GT, VanDusseldorp TA, Hester GM, Julian JM, Feito Y. The addition of β-Hydroxy β-Methylbutyrate (HMB) to creatine monohydrate supplementation does not improve anthropometric and performance maintenance across a collegiate rugby season. Journal of the International Society of Sports Nutrition. 2020;17(1):28.Randomized trialPubMed 32460801 · DOI

    What it found: Double-blind crossover study of 16 male collegiate rugby players who took HMB plus creatine (5 g of each daily) or creatine plus placebo (5 g creatine and 5 g placebo daily) for 6 weeks. The authors concluded that adding HMB to creatine offered no extra benefit over creatine alone.

    Limits: Sixteen players, 13 completed the first phase and 8 the crossover, and the trial measured maintenance across a season rather than gains.

  9. Wilson JM, Fitschen PJ, Campbell B, Wilson GJ, Zanchi N, Taylor L, et al. International Society of Sports Nutrition Position Stand: beta-hydroxy-beta-methylbutyrate (HMB). Journal of the International Society of Sports Nutrition. 2013;10(1):6.Position standPubMed 23374455 · DOI

    What it found: The first ISSN position stand on HMB. It concluded HMB can reduce exercise-induced muscle damage in trained and untrained people, that 38 mg per kilogram of body weight a day supports gains in hypertrophy, strength, and power, that calcium HMB and free acid HMB are both used with insufficient evidence to rank them, and that HMB is safe for chronic use in young and older people.

    Limits: A 2013 consensus statement superseded by the 2025 update; its lead author also led the disputed 2014 HMB free acid trial, and its competing-interests section says one co-author was conducting research for Metabolic Technologies Inc.

  10. Molfino A, Gioia G, Rossi Fanelli F, Muscaritoli M. Beta-hydroxy-beta-methylbutyrate supplementation in health and disease: a systematic review of randomized trials. Amino Acids. 2013;45(6):1273-1292.Systematic reviewPubMed 24057808 · DOI

    What it found: Systematic review of HMB trials: 13 in healthy trained young people, 11 in healthy untrained young people, 9 in patients with chronic diseases, and 6 in elderly subjects. The authors concluded HMB helps prevent exercise-related muscle damage and limits muscle loss in chronic disease, that the usual dose is 3 g a day, and that well-designed trials are still needed.

    Limits: A 2013 review, so it predates the newer meta-analyses that found little or no effect in trained people.

  11. Rahimi MH, Mohammadi H, Eshaghi H, Askari G, Miraghajani M. The Effects of Beta-Hydroxy-Beta-Methylbutyrate Supplementation on Recovery Following Exercise-Induced Muscle Damage: A Systematic Review and Meta-Analysis. Journal of the American College of Nutrition. 2018;37(7):640-649.Meta-analysisPubMed 29676656 · DOI

    What it found: Meta-analysis of randomized trials using creatine kinase (CK) and lactate dehydrogenase (LDH) as indirect markers of muscle damage. Across 10 CK studies (324 participants) HMB lowered CK (weighted mean difference -60.71 U/L, 95% CI -78.12 to -43.29) and across 8 LDH studies (229 participants) it lowered LDH (-15.42 U/L, 95% CI -22.2 to -8.6), and a subgroup analysis found the effect significant in studies over 6 weeks.

    Limits: CK and LDH are blood markers of damage, not measures of performance or soreness, and the trials were small.

  12. Optimum Nutrition. HMB 1000 CAPS. optimumnutrition.com, November 5, 2026.Product pageRead

    What it found: The maker's page for HMB Caps: a serving is 3 capsules, there are 30 servings (90 capsules) per container, and a serving gives 3 g of calcium HMB (listed as "Calcium Beta-hydroxybutyrate Beta-methylbutyrate Monohydrate"). The directions say to take 3 capsules daily, and the page names no third-party certification and its product description does not mention creatine.

    Limits: The page also says "Every capsule contains 3g of pure HMB," which conflicts with 3 g per 3-capsule serving, and the Supplement Facts panel is an image, so other ingredients were not read.

  13. Optimum Nutrition. Creatine Gummies. optimumnutrition.com, November 5, 2026.Product pageRead

    What it found: The maker's page for its creatine gummies: 5 g of creatine monohydrate per serving of 3 gummies, taken as 3 gummies daily. Outside its menu, which lists HMB 1000 Caps as a separate product, the page does not mention HMB, and it names no third-party certification.

    Limits: The page gives sugar as 0 g in one place and 2 g in another, cites no studies on the gummies themselves, and shows no gummy count per container.

  14. Rowlands DS, Thomson JS. 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. Journal of Strength and Conditioning Research. 2009;23(3):836-846.Meta-analysisPubMed 19387395 · DOI

    What it found: Meta-analysis of nine studies (14 comparisons, 394 subjects, mean age 23) of HMB during resistance training. In untrained men HMB gave small benefits to lower-body strength (9.9%) and average strength (6.6%), with negligible upper-body gains (2.1%); strength effects were trivial in trained men, and fat and fat-free mass effects were trivial.

    Limits: Young men only, short studies (about 5 weeks), and the data are older than most current trials.

  15. Wu H, Xia Y, Jiang J, Du H, Guo X, Liu X, et al. Effect of beta-hydroxy-beta-methylbutyrate supplementation on muscle loss in older adults: a systematic review and meta-analysis. Archives of Gerontology and Geriatrics. 2015;61(2):168-175.Meta-analysisPubMed 26169182 · DOI

    What it found: Meta-analysis of seven randomized trials in adults aged 65 and older (147 receiving HMB, 140 controls). HMB produced greater muscle mass gain than control (SMD 0.352, 95% CI 0.11 to 0.594, P = 0.004) with no significant change in fat mass.

    Limits: Seven small trials pooled with a fixed-effects model, and the authors call for more research on strength and physical function.

  16. Bear DE, Cruz-Jentoft AJ, Stout JR. β-hydroxy-β-methylbutyrate supplementation in older persons - an update. Current Opinion in Clinical Nutrition and Metabolic Care. 2021;24(1):48-52.ReviewPubMed 33148945 · DOI

    What it found: Review of recent HMB evidence in hospitalized and community-dwelling older adults. It found no new hospital-based studies in the prior 2 years apart from one post hoc analysis, and three community-dwelling studies whose methodological quality was suboptimal, so the authors call for high-quality studies in both settings.

    Limits: A short narrative update with no pooled numbers.

  17. Fernández-Landa J, Calleja-González J, León-Guereño P, Caballero-García A, Córdova A, Mielgo-Ayuso J. 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. Nutrients. 2019;11(10):2528.Systematic reviewPubMed 31635165 · DOI

    What it found: Systematic review that included six articles on creatine monohydrate plus HMB. Of the strength studies 1 of 2 showed improvement, of the anaerobic studies 2 of 3, and the one aerobic study showed none, and the 4 muscle-damage studies and 1 hormone study showed no benefit; the authors concluded 3 to 10 g/day of creatine plus 3 g/day of HMB for 1 to 6 weeks may benefit strength and anaerobic performance.

    Limits: Only six small, short studies with mixed results, and no meta-analysis pooling.

  18. Ramos-Hernández R, Miguel-Ortega Á, Martínez-Ferrán M, Fernández-Lázaro D, Busto N, Mielgo-Ayuso J. Combined creatine and HMB co-supplementation improves functional strength independent of muscle mass in physically active older adults: a randomized crossover trial. GeroScience. 2026;48(3):4457-4475.Randomized trialPubMed 41073834 · DOI

    What it found: Randomized, double-blind, placebo-controlled crossover trial of 30 adults aged 60 or older (20 men, 10 women) who did two 6-week periods of creatine monohydrate plus HMB or placebo, separated by a 3-week washout, with four supervised exercise sessions a week. Creatine plus HMB improved several functional strength and endurance tests, largely independent of muscle mass changes.

    Limits: Thirty people, 6 weeks, body composition by bioelectrical impedance, the abstract gives no doses or effect sizes, and it cannot separate creatine's effect from HMB's.

  19. Patrick R. Q&A #36: How Much Protein After 50?—Sources, Timing, & Leucine. FoundMyFitness, June 4, 2022.PodcastListen

    What it found: Rhonda Patrick's Q&A episode. At 00:53:24 a listener asks about supplementing with hydroxymethylbutyrate (HMB) to preserve muscle with age; in the transcript she says she did not ask Stuart Phillips about it and that she does not know whether HMB adds anything on top of protein, omega-3, vitamin D, and creatine.

    Limits: A spoken answer to one listener question with no studies cited, so it shows her uncertainty, not a review of the evidence.