HMB, or beta-hydroxy beta-methylbutyric acid, is an active metabolite of the amino acid leucine, meaning a portion of leucine is metabolized into HMB once in the body. Leucine is the branched chain amino acid most responsible for protein synthesis, or muscle growth. HMB, in its supplemental from, is commonly used by bodybuilders or athletes who are interested in increasing the benefits of strength training.
Present in insignificant quantities in: