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 vs Glutathione: Comparing Antioxidant Powerhouses for Your Health IVDrips NAC is one of those supplements that I always have on hand. It's impressive how broadly supportive NAC is. One time I was taking NAC 500 mg every day for about two Effects of N acetylcysteine, oral glutathione (GSH) and a novel sublingual form of GSH on oxidative stress markers: A comparative crossover study. ScienceDirect NAC Dr. Randolph's Wellness Store