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 Glutathione Injections Glutathione is the body's master antioxidant. It is important for handling oxidative stress, detoxification, and immune health. Low glutathione is linked to many chronic illnesses. Knowing what your body needs to make Natural Factors N Acetyl L Cysteine 500mg Body Energy Club Cysteine metabolic circuitries: druggable targets in cancer British Journal of Cancer