Green Valley Health and Herbs Serving Elmira for over 30 years 6 Facts About NAC: The Powerful Glutathione Precursor 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 A C (N Acetyl L Cysteine) Reference Guide Jarrow Formulas NAC Precursor to Glutathione, Support Lungs Liver 600 MG 3 BOTTLES 180 Caps eBay