a naturally occurring substance that is metabolized into the AMINO ACID CYSTEINE. Cysteine is one of the three components of the major cellular ANTIOXIDANT GLUTATHIONE, and people with HIV have decreased levels of this compound. Taking NAC will restore glutathione levels, but it remains to be proven whether this increase in glutathione has clinical benefit. See also OXIDATIVE STRESS.

An antioxidant drug that may keep cancer cells from developing or reduce the risk of growth of existing cancer.