“Glutathione (GSH) is the most abundant intracellular antioxidant, the backbone of natural defenses against ROS. It is a tripeptide composed of glycine, cysteine, and glutamic acid. GSH levels decline with age, so supplementing it could plausibly affect other processes of aging.”

https://www.lifespan.io/news/glutathione-extends-lifespan-in-mice-by-24/