Glutathione (GSH) is a tripeptide with a gamma peptide linkage between the amine group of cysteine and the carboxyl group of the glutamate side-chain. It is an antioxidant, preventing damage to important cellular components caused by reactive oxygen species such as free radicals and peroxides. Glutathione exists in both reduced (GSH) and oxidized (GSSG) states.
 
Glutathione’s multiple functions include: Participating directly in the neutralization of free radicals and reactive oxygen compounds, as well as maintaining exogenous antioxidants such as vitamins C and E in their reduced (active) forms; Being used in metabolic and biochemical reactions such as DNA synthesis and repair, protein synthesis, prostaglandin synthesis, amino acid transport, and enzyme activation; Playing a vital role in iron metabolism; Regulation of the nitric oxide cycle.