Structural SupportHealthy Skin, Hair and NailsWith Vitamin B-6 and CNon-GMOA Dietary SupplementKosherAmino AcidsFamily Owned Since 1968GMP Quality AssuredCysteine is a non-essential sulfur amino acid, which plays a critical role in methionine, taurine and glutathione metabolism. It is also an important component of hair, nails and the keratin of the skin. Cysteine stabilizes protein structure and aids in the formation of collagen, being thereby indispensable to skin, hair and nail health.