Hydroxy-methyl-butyrate (HBM)
HMB is short for hydroxy-methyl-butyrate. It is a natural compound produced in the body during metabolism, but it's also in foods such as catfish and alfalfa sprouts. HMB is one of the most expensive nutrition supplements today, and so far it has received mixed reviews from users since it was introduced to the market in 1996.
Proposed ergogenic effects
HMB is thought to prevent muscle tissue breakdown, speed up muscle repair, and increase lean body mass by reducing the amount of energy derived from protein and increasing energy derived from fat. One idea is that HMB works by preventing muscle protein breakdown during exercise. Another possibility is that HMB is a structural component of muscle cells that is destroyed under stress. HMB supplementation, therefore, may both prevent muscle breakdown as well as accelerate tissue repair after exercise.
Scientific evidence for these ergogenic effects
To date there are not many published studies looking into HMB's efficacy, and more high quality research is needed. In addition, the current research is contradictory. One study carried out in 1996 concluded that supplementation with 1.5 or 3 g HMB/day can partly prevent exercise-induced protein breakdown and/or muscle damage and result in larger gains in muscle function associated with resistance training [1]. A recent review of the research, however, stated that HMB supplementation (3 to 6 g /d) during resistance-training does not reduce catabolism or affect training- induced changes in body composition and strength in experienced resistance-trained males [2].
Side effects and warnings
- To date, studies have not shown any adverse side effects in humans from the usage of HMB. However, studies that involved human subjects were short term. More research is needed to investigate any possible side effects from long term usage.
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There is a distinct lack of scientific data on the safety of HMB when taken by children and pregnant or breast feeding women. If you fit into these categories do not take HMB.
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As with all dietary supplements, make sure that you inform your physician of what you are taking.
Points to Consider
- HMB is sold in most major, health food stores as calcium-HMB. Cost of the supplement is approximately $30 for a 10-day supply, which makes it one of the most expensive supplements on the market.
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All genuine forms of the supplement must bear the patent number, U.S. Patent 5,348,979 on the product label. Look out for this number when buying HMB.
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HMB appears to have a short half-life (2-3 hrs.) in the blood and therefore has to be taken in several divided doses throughout the day.
References
1. Nissen S, Sharp R, Ray M, Rathmacher JA, Rice D, Fuller JC, Connelly AS, Abumrad N. Effect of leucine metabolite beta-hydroxy-beta-methylbutyrate on muscle metabolism during resistance-exercise training. Journal of Applied Physiology, Vol.81, No.5, pp.2095-2104, 1996.
2. Kreider RB, Ferreira M, Wilson M, Almada AL. Effects of calcium beta-hydroxy-beta-methylbutyrate (HMB) supplementation during resistance-training on markers of catabolism, body composition and strength. International Journal of Sports Medicine, Vol.20, No.8, pp.503-509, 1999.