β-Hydroxy β-Methylbutyrate or HMB as it is otherwise known is a chemical component of a protein called leucine.
Studies have observed differences in body composition when compared to a placebo group, (1,2). Research has also found an increase in lean leg mass but not overall muscle mass, (3,4) with one study finding an increase in muscle strength after taking 1.5g/day for 24 weeks, (4).
Further research is needed however as most studies used HMB with other ingredients that may contribute in the increases observed (i.e, Caffiene, Creatine, etc….).
+ Increases Lean leg mass – No increase in total body mass
+ Increase in Leg strength – More Research needed
1 – Corona, G., Rastrelli, G., Giagulli, V. A., Sila, A., Sforza, A., Forti, G., … & Maggi, M. (2013). Dehydroepiandrosterone supplementation in elderly men: a meta-analysis study of placebo-controlled trials. The Journal of Clinical Endocrinology & Metabolism, 98(9), 3615-3626.
2 – Molfino, A., Gioia, G., Fanelli, F. R., & Muscaritoli, M. (2013). Beta-hydroxy-beta-methylbutyrate supplementation in health and disease: a systematic review of randomized trials. Amino Acids, 45(6), 1273-1292.
3 – Deutz, N. E., Pereira, S. L., Hays, N. P., Oliver, J. S., Edens, N. K., Evans, C. M., & Wolfe, R. R. (2013). Effect of β-hydroxy-β-methylbutyrate (HMB) on lean body mass during 10 days of bed rest in older adults. Clinical nutrition, 32(5), 704-712.
4 – Stout, J. R., Smith-Ryan, A. E., Fukuda, D. H., Kendall, K. L., Moon, J. R., Hoffman, J. R., … & Mustad, V. A. (2013). Effect of calcium β-hydroxy-β-methylbutyrate (CaHMB) with and without resistance training in men and women 65+ yrs: a randomized, double-blind pilot trial. Experimental gerontology, 48(11), 1303-1310.