Creatine and HMB: Five Trials, About 144 People, and Who Ran Them

Creatine and HMB is the most heavily marketed combination in the creatine aisle, and the advertising is older than most of the evidence. Together the two terms draw around 11,000 searches a month. The literature under them is five randomised trials and about 144 people — and the split between which trials found a benefit and which did not is the most informative thing in it. This page reports what was administered, measured and found, with amounts given as attributed journalism and no usage guidance, per our editorial standards.

Counting the evidence properly

A PubMed search on 2026-09-18 for HMB, hydroxymethylbutyrate or beta-hydroxy-beta-methylbutyrate together with creatine returns 132 records, of which 31 carry the randomised-controlled-trial tag.

Thirty-one would be a respectable literature. It is not this literature. Reading the 31 by title and abstract, most test HMB alone against placebo, or a multi-ingredient formula in which both appear among six or twelve other things, or use "creatine" only because creatine kinase was a blood marker. Trials with an arm that received both compounds as the intervention:

Five trials. Roughly 144 people. Arm sizes of seven to eleven. This is the same counting discipline this site applied to creatine HCl and it produces the same shape: a heavily sold ingredient with a literature an order of magnitude smaller than its marketing implies.

One footnote on the count, because it changes the picture: three separate 2026 papers report the last trial. One is the main result, one covers metabolic health and functional performance, and one is explicitly labelled a secondary analysis of the same randomised crossover. Counted as papers, recent evidence looks like a wave. Counted as trials, it is thirty people.

The founding study, read closely

Jówko and colleagues, 2001. Forty participants randomised to placebo, creatine, HMB, or both, for three weeks of progressive resistance training. Gains in lean body mass over placebo:

• creatine 0.92 kg
• HMB 0.39 kg
• both 1.54 kg

Those three numbers are why the combination is sold. The paper's conclusion — that the effects are additive — is quoted widely and almost never with its basis, which is this: "These effects were additive because there was no interaction between CR and HMB (CR × HMB main effect P = 0.73)."

That sentence is doing something a reader should see. An interaction test asks whether the data are inconsistent with the two effects simply summing. Failing to find such evidence in arms of nine to eleven people is not a demonstration that they sum; it is a study without the power to show otherwise. The same p = 0.73 would be returned by a genuinely additive pair and by a study too small to distinguish anything, and nothing in the paper separates those cases.

Two further details belong with the figures. Lean body mass was estimated by bioelectrical impedance, which reads body water and infers tissue — a method this site has already had to unpick on creatine bloating, where direct tracer measurement showed creatine moves total body water within days. In a three-week creatine trial, a water-sensitive method measuring a creatine arm is measuring partly the thing that confounds it. And HMB's own main effect in this study was a trend, p = 0.08, not a result.

The study is also not distant from its subject. Its senior author, S. Nissen, is the first author of the 1996 paper that introduced HMB as a training supplement — a fact readable from the two author lines and stated here for that reason. This site records author affiliation as evidence, not as accusation; it did the same for the collagen recovery trials, where the positive results were authored at gelatin manufacturers and the independent comparisons were null.

The independent trials in trained athletes

O'Connor and Crowe, 2007. Elite male rugby league players: control (n = 8), HMB at 3 g a day (n = 11), or a 12 g daily supplement containing 3 g HMB, 3 g creatine and 6 g carbohydrate (n = 11), for six weeks. Bench press, deadlift, prone row, shoulder press, chin-ups, a ten-second maximal cycle test, body mass, girths and skinfolds. The finding, in the authors' own summary: no effect of HMB or HMB with creatine on any parameter, against either baseline or the control group.

Mangine et al., 2020. Sixteen collegiate rugby players in a crossover, taking 5 g HMB plus 5 g creatine or 5 g creatine plus placebo for six weeks, repeated in the opposite order after a ten-week washout. The title states the result plainly — adding HMB to creatine did not improve anthropometric or performance maintenance across the season — and the paper reports that interactions did not consistently favour either regimen. Thirteen of the sixteen completed the first period and eight returned for the second, which is the trial's own limitation.

Note what is being tested in the 2020 crossover, because it is the practical question and only that trial asks it: not creatine versus nothing, but HMB added on top of creatine.

The trials that found something

Fernández-Landa et al., 2020. Twenty-eight elite rowers, seven per arm, ten weeks, creatine at 0.04 g/kg a day, HMB at 3 g a day, or both. No significant differences in body composition, nor in power at the anaerobic threshold or at 4 mmol of blood lactate. A difference appeared on one outcome, aerobic power at 8 mmol, reported at p < 0.001 with a partial eta-squared of 0.766. That effect size — roughly three-quarters of the variance attributed to the grouping — is very large for seven people per arm on one of several outcomes, and is the kind of figure that should be read as a reason to want replication rather than as a settled effect.

Ramos-Hernández et al., 2026. Thirty physically active older adults, randomised double-blind crossover, six weeks on each condition with a three-week washout, alongside four supervised training sessions a week. The headline is in the title: functional strength improved independent of muscle mass.

That phrase is worth pausing on, because this site keeps meeting it. It is the same dissociation the registry's only posted creatine before-and-after trial showed — strength up, measured muscle size flat — and the same one that holds across the growth-hormone axis, where no compound has produced more than about 1.4 kg and none produced a function benefit. Tissue and force do not move together as reliably as the marketing for either ingredient assumes.

The 2020 rowing trial and the 2026 crossover share investigators, including the senior author of both.

What can honestly be said

The combination has been tested five times in about 144 people. The two trials in trained athletes run by investigators with no stake in either compound found no added benefit. The trials reporting a benefit are the founding study, co-authored by the researcher who introduced HMB, and one crossover in older adults from a single group, published three times.

That is not a finding that the pairing fails. It is a finding that the question has not been asked often enough, or in large enough groups, for the answer to be known — and that the way the evidence divides, by who ran the trial and in whom, is at least as informative as the direction of any single result.

For creatine on its own, where the literature runs to hundreds of trials rather than five, see what creatine is and creatine benefits. For the pairing people ask about more often, see creatine and collagen peptides.

What would change this page

A creatine-plus-HMB trial with more than fifty people per arm, direct imaging rather than impedance, and a pre-registered outcome. A replication of the 2026 crossover by a group with no connection to it. Or a posted registry result for any of them — none of the five has one.

Key figures

• 132 PubMed records, 31 tagged randomised trials, 5 with both compounds in one arm.
• ~144 participants across the five, in arms of 7 to 11.
• 1.54 kg — the combined-group gain over placebo in the 2001 study, by impedance, over three weeks.
• p = 0.73 — the interaction test the additivity claim rests on.
• 0 of the two independent trials in trained athletes found an effect of the combination.
• 3 papers, 1 trial, 30 people — the 2026 evidence.

This page reports what studies administered and measured, with sources and dates. It contains no recommendation, and decisions about supplementation belong with a clinician.

Sources

• Jówko E, Ostaszewski P, Jank M, 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):558–66 — PMID 11448573 · doi:10.1016/s0899-9007(01)00540-8
• Nissen S, Sharp R, Ray M, et al. Effect of leucine metabolite beta-hydroxy-beta-methylbutyrate on muscle metabolism during resistance-exercise training. J Appl Physiol 1996;81(5):2095–104 — PMID 8941534 · doi:10.1152/jappl.1996.81.5.2095
• O'Connor DM, Crowe MJ. Effects of six weeks of beta-hydroxy-beta-methylbutyrate (HMB) and HMB/creatine supplementation on strength, power, and anthropometry of highly trained athletes. J Strength Cond Res 2007;21(2):419–23 — PMID 17530933 · doi:10.1519/R-15974.1
• Mangine GT, VanDusseldorp TA, Hester GM, et al. The addition of β-Hydroxy β-Methylbutyrate (HMB) to creatine monohydrate supplementation does not improve anthropometric and performance maintenance across a collegiate rugby season. J Int Soc Sports Nutr 2020;17(1):28 — PMID 32460801 · doi:10.1186/s12970-020-00359-4
• Fernández-Landa J, Fernández-Lázaro D, Calleja-González J, et al. Effect of Ten Weeks of Creatine Monohydrate Plus HMB Supplementation on Athletic Performance Tests in Elite Male Endurance Athletes. Nutrients 2020;12(1):193 — PMID 31936727 · doi:10.3390/nu12010193
• Ramos-Hernández R, Miguel-Ortega Á, Martínez-Ferrán M, et al. 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):4457–75 — PMID 41073834 · doi:10.1007/s11357-025-01889-y
• Ramos-Hernández R, Busto N, Miguel-Ortega Á, et al. Combined creatine and β-hydroxy-β-methylbutyrate supplementation with integral conditioning exercise enhances functional performance and metabolic health in physically active older adults. Aging Clin Exp Res 2026;38(1):44 — PMID 41511610 · doi:10.1007/s40520-025-03312-0
• Ramos-Hernández R, Mielgo-Ayuso J, Fernández-Lázaro D, et al. Creatine plus β-Hydroxy-β-Methylbutyrate supplementation is associated with preserved glutathione redox-balance… a secondary analysis of a randomized crossover trial. Biogerontology 2026;27(2):58 — PMID 41712056 · doi:10.1007/s10522-026-10407-2
• National Library of Medicine. PubMed — census searches for HMB with creatine, run 2026-09-18 — pubmed.ncbi.nlm.nih.gov

All sources retrieved 2026-09-18. Literature counts are as of that date.