NAC supplies N-acetyl-L-cysteine, which is more stable and better absorbed than its derivative, L-cysteine. NAC functions as a potent antioxidant, protecting cells against oxidative stress.* As the precursor to glutathione intracellular synthesis, NAC is essential for the synthesis of glutathione. Glutathione is a critical component of the immune system, as it is an important intracellular water-soluble antioxidant.* As part of this function, glutathione plays a vital role as the cofactor for the antioxidant enzymes glutathione peroxidase and glutathione transferase. Glutathione is also important to the liver, as the liver utilizes it for drug detoxification.* As a metabolite of cysteine, NAC plays an important role in detoxification, and is hepatoprotective.* NAC is also involved in the development of the central nervous system.