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HMB has virtually no effect, says meta study

The bodybuilding supplement HMB does have some effect, but this is so negligible that you're better off not wasting your money on it. This is the conclusion that sports scientists at Massey University in New Zealand drew after doing a meta-analysis of all the reliable studies on HMB that they could find.

HMB or hydroxy methyl butyrate occurs naturally in the human body. It's a leucine metabolite. In the 1990s, researcher Steve Nissen launched HMB as a bodybuilding supplement and built up a successful company based on this amino acid. Unlike many other supplements manufacturers, Nissen researched whether HMB really did work, and as a result was able to show that HMB did have a muscle building effect.

But that's also the big problem with HMB. Most of the studies on its effect can be linked to Nissen. Nissen even produced meta-studies on the effect of HMB. But how reliable are the test results of a baker who tests his own bread?

The New Zealanders recently published the results of a trial in which they gave HMB to bodybuilders, and which show that HMB has virtually no effect. Because they wanted to know what had come out of other studies, they did their own meta-analysis. They confined their analysis to studies in which test subjects not only took HMB but also did weight training. They found nine, involving a total of four hundred test subjects.

The average length of study was five weeks. The dose that was tested varied from 3 to 6 grams of HMB per day.

The figure below shows the effect of HMB on strength. The researchers made a distinction between experiments in which the test subjects had never worked with weights before and studies involving experienced strength athletes.

HMB has virtually no effect, says meta study

For experienced athletes the effect was trivial, in other words very small. For inexperienced athletes the effect is slightly bigger.

It's not exactly encouraging. But brace yourself: the worst is still to come. When the researchers examined the effect of HMB on body composition, it turned out to be almost nil.

HMB has virtually no effect, says meta study

"For previously untrained individuals starting a resistance training program, small gains in lower-body and overall strength with HMB supplementation may be expected during the first 12 months", the researchers conclude. "However, the absence of even small benefits to lean mass gain and body fat reduction in both untrained and trained lifters, and the trivial effect on strength in well-trained lifters, suggest that, over the short term, this supplement is of negligible worth to the majority of experienced athletes".

J Strength Cond Res. 2009 May;23(3):836-46.

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