β-hydroxy-β-methylbutyric acid

β-Hydroxy-β-methylbutyric acid (HMB) is a naturally occurring metabolite of the essential amino acid leucine. It is produced in small amounts in the human body and can also be taken as a dietary supplement. HMB is primarily used to promote muscle growth and prevent muscle breakdown (catabolism), especially in individuals undergoing resistance training or experiencing muscle wasting due to aging or chronic illness. Mechanistically, HMB stimulates protein synthesis via activation of the PI3K/Akt/mTOR pathway and inhibits protein degradation by suppressing the ubiquitin-proteasome proteolytic pathway. It may also have neurotrophic effects and improve vascular endothelial function[4][5][8]. HMB is available over-the-counter as both a free acid (HMB-FA) and as calcium salt (calcium β-hydroxy-β-methylbutyrate). It has been included in medical foods for patients with cachexia or sarcopenia[5][8].

Brand names

CaHMB 3000CaHMB3000CaHMB-3000

Other names

hydroxymethylbutyratebeta-hydroxy-beta-methylbutyrateHMB free acid3-hydroxy-3-methylbutanoic acid