Leucic acid, also called HICA (alpha-hydroxyisocaproic acid), is a metabolite of the branched-chain amino acid leucine. Supplement brands market it for exercise recovery and muscle maintenance. The evidence comes from small, short-term studies, and the findings are still preliminary.
People take leucic acid around workouts or during periods of reduced activity. They hope it slows muscle breakdown and helps the body repair after exercise. Capsule and powder forms are typical.
Safety data are thin. Some trials report stomach upset. Check with a professional before adding it to your routine.