As I mention in my book, N acetyl cysteine (NAC) is not found in food sources, but in the body, it converts into cysteine. NAC acts as a precursor to glutathione, a powerful N acetylcysteine reduces the hepatic complications of social isolation stress through modulation of interleukin 1 and 6 gene expression and liver enzymes in mice Scientific Reports Glutathione: Master Antioxidant, Reducing Oxidative Stress, and Detoxification Acetylcysteine Wikipedia