Beta-hydroxy-beta-methylbutyrate is a metabolite of the amino acid Leucine that has mixed results on factors important to the bodybuilder when it comes to the scientific literature. It has been shown to increase strength in some studies while in others it has shown either no effect or only slight increases in strength or body composition. It has been shown in cancer patients to prevent muscle wasting and increase body weight, which is why it was theorized to be an anabolic agent in healthy adults (1). Most recent studies have shown that HMB supplements provide some possible benefit to strength, muscle recovery, muscle size or exercise physiology to significant levels but the results are not conclusive(2,3,4). Like many supplements dose is the key to this and it’s unclear what dose is optimal for sports supplementation. Even at 3g per day, which is high for HMB, the results are not spectacular. It would seem that based on the dose required to get an effect, that HMB is simply not worth the money.
With a supplement that has mixed results, it usually goes to the anecdotal reports to help break the tie. Unfortunately, the results on anecdotal reports are just as mixed, making this ingredient one to watch, but not currently recommended for the bodybuilder compared to other more proven supplements.
1. Aversa Z, Bonetto A, Costelli P, Minero VG, Penna F, Baccino FM, Lucia S, Rossi Fanelli F, Muscaritoli M. β-hydroxy-β-methylbutyrate (HMB) attenuates muscle and body weight loss in experimental cancer cachexia. Int J Oncol. 2010 Dec 23. doi: 10.3892/ijo.2010.885.
2. Portal S, Eliakim A, Nemet D, Halevy O, Zadik Z. J Effect of HMB supplementation on body composition, fitness, hormonal profile and muscle damage indices. Pediatr Endocrinol Metab. 2010 Jul;23(7):641-50.
3. Nunan D, Howatson G, van Someren KA. Exercise-induced muscle damage is not attenuated by beta-hydroxy-beta-methylbutyrate and alpha-ketoisocaproic acid supplementation. J Strength Cond Res. 2010 Feb;24(2):531-7.
4. Thomson JS, Watson PE, Rowlands DS. Effects of nine weeks of beta-hydroxy-beta- methylbutyrate supplementation on strength and body composition in resistance trained men. J Strength Cond Res. 2009 May;23(3):827-35.