What is HMB?
HMB (β-hydroxy-β-methylbutyrate) is a metabolite of the branched chain amino acid, leucine. A 70-kg person produces only about 0.2 to 0.4 g of HMB daily; this quantity may not be sufficient to support metabolic needs during times of stress and healing. Commercial supplements containing HMB are available to provide additional amounts of HMB. Studies in animals and in humans demonstrated that HMB increases protein synthesis and decreases protein degradation. Traditionally, HMB has been used by athletes to enhance performance and build muscle mass. Recent research has focused on the use of HMB to preserve or rebuild muscle mass in populations in whom loss of lean body mass (LBM) would increase risk for injury, disability, or mortality. This research has demonstrated the benefits of HMB supplementation along with other amino acids (eg, arginine and glutamine) in rebuilding LBM in older adults, as well as in persons with chronic diseases, such as acquired immune deficiency syndrome and cancer.
Clark RH, Feleke G, Din M, et al. Nutritional treatment for acquired immunodeficiency virus-associated wasting using β-hydroxy β-methylbutyrate, glutamine, and arginine: a randomised, double-blind, placebo controlled study. JPEN J Parenter Enteral Nutr 2000;24:133-9.
Flakoll P, Sharp R, Baier S, Levenhagen D, Carr C, Nissen S. Effect of β-hydroxy-β-methylbutyrate, arginine, and lysine supplementation on strength, functionality, body composition, and protein metabolism in elderly women. Nutrition 2004;20:445-51.
May PE, Barber A, D'Olimpio JT, Hourihane A, Abumrad NN. Reversal of cancer-related wasting using oral supplementation with a combination of β-hydroxy-β-methylbutyrate, arginine, and glutamine. Am J Surg 2002;183:471-9.
Vukovich MD, Stubbs NB, Bohlken RM. Body composition in 70-year-old adults responds to dietary β-hydroxy-β-methylbutyrate similarly to that of young adults. J Nutr 2001;131:2049-52.
Wilson GJ, Wilson JM, Manninen AH. Effects of β-hydroxy-β-methylbutyrate (HMB) on exercise performance and body composition across varying levels of age, sex, and training experience: a review. Nutr Metab 2008;5:1.