Glutathione Wikipedia Glycine and N acetylcysteine (NAC) are amino acidbased nutrients that serve as precursors for glutathione, one of the body's most important intracellular antioxidants. Glutathione plays a central role in reducing oxidative stress, supporting Our ancestors ate whole animals. Skin, cartilage, tendons, bones, organs. That meant they consumed massive amounts of glycine from collagen rich tissues. Modern humans eat almost exclusively muscle meat, which is extremely high NAC [N AcetylCysteine] is a precursor of Glutathione. PICTURE: Glutathione is made from three amino acids and cysteine is one of them