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 Exploring the Evidence of N Acetyl Cysteine (NAC) for Mood Disorders Psychopharmacology Institute Glutathione 101, Part 1: Cysteine Misbehaves, But Glutathione Saves The Weston A. Price Foundation Supporting Your Immune System Naturally with Glutathione Dr Hagmeyer Glutathione: The Master Antioxidant Core Med Science