Molecular Classification
Metabolite, Small molecule
Other Names
beta-hydroxy beta-methylbutyrate, β-hydroxy β-methylbutyric acid, 3-hydroxy-3-methylbutanoic acid, 3-hydroxyisovaleric acid, HMB
Disease Roles
Muscle wasting in cancer/HIV/AIDSAge-related muscle loss (sarcopenia)Exercise recovery

Beta-hydroxy beta-methylbutyric acid Overview

Beta-hydroxy beta-methylbutyric acid (HMB) is a naturally occurring small molecule produced in humans as a metabolite of the branched-chain amino acid L-leucine. It is found in small amounts in certain foods and is also produced endogenously in the liver and muscle cells. HMB has been widely studied for its potential to stimulate muscle protein synthesis, inhibit muscle protein breakdown, increase lean body mass, and support recovery after strenuous exercise or in situations of muscle wasting such as cancer, HIV/AIDS, or age-related sarcopenia. As a dietary supplement, HMB is used mainly by athletes and elderly individuals to help preserve muscle mass and strength. It is not associated with significant adverse effects when used as directed. Importantly, HMB is a metabolite and not a protein target, receptor, enzyme, or transporter[1][5][6][7].

Mechanism of Action

HMB exerts effects by stimulating protein synthesis and inhibiting protein breakdown in muscle tissue

Biological Functions

Muscle protein synthesis and protection
Inhibit muscle breakdown
Support lean body mass in illness or aging

Disease Associations

Muscle wasting in cancer/HIV/AIDS
Age-related muscle loss (sarcopenia)
Exercise recovery
Anabolic support

Safety Considerations

  • No significant adverse effects reported in adults with long-term use as a dietary supplement