Nutricost, L-Lysine Capsules, 500 Mg, 500 CountProduct Description L lysine is an essential amino acid, meaning the body cannot produce it on its own and must obtain it through diet or supplementation. It plays a crucial role in protein synthesis, immune function, and collagen production. L lysine supplements are commonly used to support immune health Product Benefits Supports Immune Health. Collagen Production. Promotes Healthy Skin And Hair. Ingredients Supplement FactsServing Size: 2 Capsules.