Cysteine and N-Acetyl-L-Cysteine (NAC): Two Sources of Sulfur

L-Cysteine and Sulfur as Keratin Building Blocks for Hair and Nails

The amino acid cysteine (L-cysteine) is a component of nearly all proteins in the body – for example, of the structural protein keratin. Keratin provides hair and nails with their strength and structure. In addition, cysteine is an essential building block of the body’s own antioxidant, glutathione. N-acetyl-L-cysteine (NAC) is derived from cysteine and represents its stabilized form. Both micronutrients are also important sources of sulfur.