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 NAC N Acetyl Cysteine + Glutathione 120 Capsules 2028mg Antioxidant Supplement The mechanism of action of N acetylcysteine (NAC): The emerging role of H2S and sulfane sulfur species ScienceDirect Amazon.com: 2 Pack NAC Supplement (N Acetyl Cysteine) 1,000mg Serving with Reduced Glutathione, 480 Capsules : Health & Household A new opportunity for N acetylcysteine. An outline of its classic antioxidant effects and its pharmacological potential as an epigenetic modulator in liver diseases treatment Naunyn Schmiedeberg's Archives of Pharmacology Springer Nature