What is HMB? HMB (Beta-hydroxy-beta-methylbutyrate) is a metabolite, derived from the amino acid leucine, and its keto acid, alpha-ketoisocaporate. Only about 5% of the leucine in our diet is converted to HMB (Gatnau, et al., 1995). HMB appears to have anti-catabolic properties. This means that it slows down the rate at which muscle tissue is broken down in our own body. This is supported by research that suggests HMB reduces the amount of exercise induced muscle damage (Knitter et al., 2000).
Who might benefit from HMB supplements? Anyone training intensively in strength, power or endurance based sports will benefit from HMB supplementation. HMB may also aid weight loss.
What does research say about HMB
Research by Knitter et al., 2000, found that following 6-weeks of HMB
supplementation, runners experienced 58% less muscle cell damage than athletes
that were not taking HMB, following a 20-km run. Muscle damage was found to
still be 9% lower in the HMB group four days after the 20-km run.
Early research on HMB by Nissen et al., 1996a, found that HMB supplementation can increase muscle mass by 1.2kg over a three week period when taken as a daily 3-gram supplement and combined with resistance training. Further research by Nissen et al., 1996b, found that HMB supplementation led to increased muscle mass - three times greater than the placebo group - and muscle strength - two times greater than the placebo group. In this study, 1.5-3g of HMB, reduced the amount of exercise proteolysis (muscle breakdown) and or muscle damage and resulted in larger gains in muscle function associated with resistance training.
In a review of current HMB research by Alon et al., 2002, concluded that HMB supplementation plays an important role in reducing protein breakdown and/or increasing the recovery of damaged muscle cells. They concluded that HMB supplementation “could be advantageous to all individuals participating in exercise programs and improve the lives of many”. Interestingly, HMB supplementation has been shown to be equally effective when used by elderly individuals with up to 20% increases in protein synthesis (muscle building process), increases in fat-free mass, decreased percentage body fat, and increased strength (Vukovich et al., 2001; Flakoll et al., 2004).
Further research (Vukovich and Adams, 1997) looked at the effect of HMB supplementation on endurance cycling performance. In this Research study HMB supplementation led to significant increases in the time taken to reach VO2max and the lactate threshold. Therefore, as well as improving muscular strength, HMB also has the potential to improve endurance performance.
HMB supplementation appears to be less effective when used by highly trained athletes, than by less well trained athletes (Kreider et al., 1999; Slater et al., 2001).
How should I take HMB? Research has generally found HMB to be effective when taken at a dose of approximately 2-4g per day. The dose is dependant on the size of the athlete: heavy athletes may need a dose of 3-4g per5 day, whereas lighter athletes may only need 2g per day. The dose should be split up throughout the day, with meals, as the body is unable to utilise large doses of HMB at one time, and any excess will be excreted and therefore wasted. Endurance athletes may find HMB to be particularly effective at reducing the amount of exercise induced muscle damage and speeding up the rate of recovery between sessions.
Alon, T., Bagchi, D. and Preuss, H. G. (2002) Supplementing with beta-hydroxy-beta-methylbutyrate (HMB) to build and maintain muscle mass: a review. Res Commun Mol Pathol Pharmacol. 111 (1-4), 139-151.
Flakoll, P., Sharp, R., Baier, S., Levenhagen, D., Carr, C. and Nissen, S. (2004) Effect of beta-hydroxy-beta-methylbutyrate, arginine, and lysine supplementation on strength, functionality, body composition, and protein metabolism in elderly women. Nutrition. 20 (5), 445-451.
Gatnau, R., Zimmerman, D. R., Nissen, S. L., Wannemuehler, M. and Ewan, R. C. (1995) Effects of excess dietary leucine catabolites on growth and immune responses in pigs. Journal of Animal Sciences. 73, 159-165.
Knitter, A. E., Panton, L., Rathmacher, J. A., Petersen, A. and Sharp, R. (2000) Effects of b-hydroxy-b-methylbutyrate on muscle damage after a prolonged run. Journal of Applied Physiology. 89, 1340-1344.
Kreider, R. B., Ferreira, M., Wilson, M. and Almada, A. L. (1999) Effects of calcium beta-hydroxy-beta-methylbutyrate (HMB) supplementation during resistance-training on markers of catabolism, body composition and strength. Int J Sports Med. 20 (8), 503-509.
Nissen, S. et al., (1996a). Effect of HMB supplementation on strength and body composition of trained and untrained males undergoing intense resistance training. FASEB J, 10 (3), A287.
Nissen, S., sharp, R., Ray, M., Rathmacher, J. A., Rice, D., Fuller, J. C. Connelly, A. S. and Abdumrad, N. (1996b) Effect of leucine metabolite beta-hydroxy-beta-methylbutyrate on muscle metabolism during resistance-exercise training. Journal of Applied Physiology. 81, 2095-2104.
Slater, G., Jenkins, D., Logan, P., Lee, H., Vukovich, M., Rathmacher, J. A. and Hahn, A. G. (2001) Beta-hydroxy-beta-methylbutyrate (HMB) supplementation does not affect changes in strength or body composition during resistance training in trained men. Int J Sport nutr Exerc Metab. 11 (3), 384-396.
Vukovich, M. D. and Adams, G. D. (1997) Effect of HMB on VO2peak and maximal lactate in endurance-trained cyclists. Medicine and Science in Sports and Exercise. 29, 5, S252, 1432.
Vukovich, M. D., stubbs, N. B. and Bolhein, R. N. (2001) Body composition in 70-year-old adults responds to dietary beta-hydroxy-beta-methylbutyrate similar to that of young adults. J Nutr. 131 (7), 2049-2052.
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