L-Isoleucine USP is an essential branched-chain amino acid (BCAA) required for protein synthesis, muscle repair, and energy regulation. It cannot be produced by the body and must be obtained through diet or supplementation. Widely used in pharmaceuticals, nutraceuticals, and sports nutrition, L-Isoleucine supports endurance, recovery, and metabolic balance. Its USP grade ensures high purity and suitability for medical and nutritional applications.