HMB (beta-hydroxy beta-methylbutyrate) is produced in the body from proteins containing the amino acid leucine. We eat it every day and our bodies naturally produce HMB.
HMB seems to have a significant role in the way our bodies build new muscle tissue and burn fat. Tests have shown that in individuals who consumed supplemental HMB and performed weight-training exercise, HMB appeared to minimize the muscle tissue breakdown which occurs after strenuous activity. Owing to less muscle damage, the body appears to speed up the rate at which it builds new muscle tissue and as consequence seems to burn more fat.
The theory behind this is that HMB helps to prevent a phenomenon known as proteolysis, which is the natural process of breaking down muscle that occurs after strenuous activity. The supplementation of HMB may help the body by minimising the amount of muscle damage and protein degradation after exercise. This suggests HMB is a building block for intra-muscular cholesterol which your muscle needs after vigorous exercise to repair itself and grow.