Glutathione is a molecule found in mammalian bodies. It is an antioxidant that plays an important role in preventing oxidative damage to the skin. In addition to its many recognized biological functions, glutathione has also been associated with skin lightening or whitening ability. The role of glutathione as a skin whitener was discovered as a side effect of large doses of glutathione.Glutathione utilizes different mechanisms to exert its action as skin whitening agent at various levels of melanogenesis. It inhibits melanin synthesis by means of stopping L-DOPA's ability to interact with tyrosinase in the process of melanin production. Research results from a study shows that glutathione inhibits the actual production as well as agglutination of melanin by interrupting the function of L-DOPA. Another study found that glutathione inhibits melanin formation by direct inactivation of the enzyme tyrosinase by binding and chelating copper within the enzyme's active site.
Glutathione's antioxidant property allows it to inhibit melanin synthesis by quenching of free radicals and peroxides that contribute to tyrosinase activation and melanin formation. Its antioxidant property also protects the skin from UV radiation and other environmental as well as internal stressors that generate free radicals that cause skin damage and hyper-pigmentation. In most mammals, melanin formation consists of eumelanin (brown-black pigment) and pheomelanin ( yellow-red pigment) as either mixtures or co-polymers. Increase in glutathione level may induce the pigment cell to produce pheomelanin instead of eumelanin pigments. (1)
Research found lowest levels of reduced glutathione to be associated with eumelanin type pigmentation, whereas the highest ones were associated with the pheomelanin. As a result, it is reasonable to assume that depletion of glutathione would result in eumelanin formation. Prota observed that decreased glutathione concentration lead to in the conversation of L-dopaqunione to L-dopachrome increasing the formation of brown-black pigment (eumelanin). (2)
Glutathione for skin whitening is available in pills, cream, soap, lotion, nasal spray and injectable form. Glutathione can be combined with many other agents like vitamin C to increase its absorption, N-acetyl cysteine to boost its level, and other antioxidants like vitamin E.