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Analysis v1
Strong Support

Taking HMB supplements does not significantly increase muscle growth in people who already eat enough protein, but might slightly affect muscle growth when calorie intake is very low or training intensity is extremely high.

65
Pro
0
Against

Evidence from Studies

Supporting (4)

65

Community contributions welcome

60

A double-blind placebo controlled trial into the impacts of HMB supplementation and exercise on free-living muscle protein synthesis, muscle mass and function, in older adults

Randomized Controlled Trial
Human
2019 Oct

HMB didn’t make older men much stronger or bigger than exercise alone, but it did help them gain a little more muscle over time—so it’s not useless, just not a huge boost.

45

The Influence of Acute Beta-Hydroxy Beta-Methylbutyrate (HMB) Ingestion on the Human Skeletal Muscle Transcriptome

Cross-Sectional Study
Human
2026 Jan 28

This study shows that HMB triggers genes in muscles that help build and repair muscle tissue, similar to how protein does. It doesn’t prove HMB makes muscles bigger, but it does show HMB is doing something helpful at the cellular level.

45

Effects of beta-hydroxy-beta-methylbutyrate supplementation on strength and body composition in trained and competitive athletes: A meta-analysis of randomized controlled trials.

Systematic Review With Meta-Analysis
Human
2018 Jul

This study looked at whether HMB supplements help athletes build muscle and found no real benefit, even in people training hard or eating lots of protein. So, it supports the idea that HMB doesn’t do much for muscle growth.

39

Does HMB Enhance Body Composition in Athletes? A Systematic Review and Meta-analysis

Systematic Review With Meta-Analysis
2022 Feb 1

This study found that HMB supplements don’t really help build muscle if you’re already eating enough protein, but might help a tiny bit if you’re training super hard or not eating enough calories.

Contradicting (0)

0

Community contributions welcome

No contradicting evidence found

Gold Standard Evidence Needed

According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.

Similar Assertions

Taking HMB-free acid supplements raises levels of HMB in the blood of older men, but this does not lead to greater improvements in muscle building, gene activity, or physical function than resistance training by itself.

60
0
79%

Taking 3 grams of HMB daily may increase muscle growth in resistance-trained adults only when they are under high training stress or not consuming enough calories; in well-fed, trained individuals, it typically has little to no effect on muscle growth.

2
0
79%

In older men doing strength training, taking HMB-free acid caused a short-term rise in muscle protein synthesis during the first two weeks, but this effect disappeared after that and was not different from taking a placebo. Any muscle growth from this supplement is not due to a lasting increase in protein synthesis.

60
0
79%

HMB, a supplement used by athletes, may only help increase fat-free mass in those who eat less than 1.6 grams of protein per kilogram of body weight each day. For athletes consuming more protein, HMB does not appear to provide additional benefit.

39
0
78%

Taking HMB supplements does not lead to a meaningful change in total body weight for athletes, based on data from multiple studies.

39
0
78%

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