Ursolic acid is a naturally occurring compound found in the peels of apples, basil, rosemary, and other plants. Its potential effects on muscle health have been investigated in both animal and limited human studies. Preclinical research, particularly in mice, has shown that ursolic acid supplementation can increase muscle mass and strength, possibly by enhancing insulin/IGF-1 signaling and reducing muscle atrophy pathways. For example, a 2011 study in Cell Metabolism reported that ursolic acid increased skeletal muscle mass and brown fat, while reducing obesity and improving glucose tolerance in mice (Kunkel et al., 2011).

Human evidence is limited but emerging. Small randomized controlled trials have suggested that ursolic acid supplementation, particularly when combined with resistance training, may help increase muscle mass and strength in older adults. However, results are mixed, and larger, higher-quality trials are still needed to confirm these effects. No major safety issues have been reported at typical supplement doses.

In summary, ursolic acid is being explored for its muscle-supporting properties based on promising animal studies and early human data. However, the overall quality and quantity of evidence in humans remain limited, so its use for muscle support should be considered preliminary.