Effects of N acetylcysteine, oral glutathione (GSH) and a novel sublingual form of GSH on oxidative stress markers: A comparative crossover study. ScienceDirect N acetyl l cysteine averts ferroptosis by fostering glutathione peroxidase 4 ScienceDirect 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 Medical Countermeasures Database CHEMM