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 acetyl l cysteine averts ferroptosis by fostering glutathione peroxidase 4 ScienceDirect Drowning in cysteine Nature Metabolism Glutathione 101, Part 1: Cysteine Misbehaves, But Glutathione Saves The Weston A. Price Foundation Glutathione 101, Part 1: Cysteine Misbehaves, But Glutathione Saves The Weston A. Price Foundation Know How Glutathione Works and Its Impact on Health & Body