The mechanism of action of N-acetylcysteine (NAC): The emerging role of H2S and sulfane sulfur species

Researchers reviewed earlier cell, animal, and human studies on N-acetylcysteine, or NAC, a medicine and supplement related to the amino acid cysteine. NAC can help the body make glutathione, a major antioxidant that protects cells. The review also examined hydrogen sulfide, or H2S, a gas made by cells, and sulfane sulfur, reactive sulfur compounds that help control cell signals. The evidence suggests NAC may change these sulfur systems, but this review did not test a new group of people or show that NAC extends human life.

What this means for you: This is a biological explanation, not proof that taking NAC prevents aging or improves longevity. You can ignore this one when deciding what to buy unless a healthcare professional recommends NAC for a specific medical reason.