Glutathione is a tripeptide that functions as a primary regulator of cellular redox states. Glutathione exists primarily in its reduced form (GSH), from which the dimer glutathione disulfide is formed upon oxidation (GSSG). As a result of oxidation or enzyme-catalyzed reactions, GSH can also form disulfide bridges with proteins, resulting in protein-bound glutathione (GSSP). Glutathione deficiency in whole blood has been linked to Parkinson’s disease, HIV, liver disease, renal failure, and preeclampsia.