Gamma-glutamylcysteine is a key intermediate in the synthesis of glutathione, one of the body’s most important antioxidants. It plays a critical role in cellular defense against oxidative stress, supporting detoxification processes in the liver and protecting cells from damage caused by free radicals and reactive oxygen species. Due to its involvement in glutathione production, it is studied for its potential to boost antioxidant capacity in aging, neurodegenerative diseases, and conditions linked to oxidative damage. It has also been explored in skincare formulations for its ability to brighten skin and reduce signs of aging by supporting the skin’s natural antioxidant defenses. In research settings, it is used to modulate intracellular glutathione levels, helping scientists understand redox biology and cellular stress responses.