Promotes the synthesis of collagen Healthy immune function Lysine is an essential amino acid that must be obtained through diet or supplementation. Lysine is necessary for the production of all proteins in the body, and is required for the maintenance of the structural proteins of collagen and elastin, which make up all connective tissues such as skin, tendons and bones. Lysine is also a precursor to carnitine, which is necessary for fat metabolism and energy production. * Additionally, lysine may help support a healthy immune system and proper cardiovascular function. NOW L-Lysine is a pharmaceutical grade essential amino acid. Natural variation in color may occur in this product.