HMB plays an anticatabolic role in muscle tissue. In other words, HMB prevents muscle protein breakdown and reduces the loss of fat-free mass. These effects seem to be most pronounced during catabolic states, including cancer cachexia,[1] acquired immunodeficiency syndrome (AIDS),[2] and aging.[3][4] HMB seems to be particularly effective for preventing the age-related loss of muscle mass and for preserving strength and body composition in bedridden or sedentary older adults.[3][4]
HMB stimulates muscle protein synthesis, but supplementation fails to increase fat-free mass, improve body composition, or increase measures of strength performance in athletes and trained individuals, and its use in these populations cannot be recommended.[5][6][7] HMB may be effective for reducing exercise-associated muscle damage after high-intensity exercise.[8]