NAC (N-Acetylcysteine)
- Effective dose
- 600–1200 mg
- Evidence
- 3/5· Moderate
Last updated June 1, 2026
What it is
N-acetylcysteine is a modified form of the amino acid cysteine and a direct precursor to glutathione, the body's main intracellular antioxidant. It also breaks disulfide bonds in mucus, which is why it has long been used medically to thin secretions and to treat acetaminophen overdose.
Benefits
NAC replenishes glutathione and has well-established mucolytic use, with around 600 mg/day used in chronic bronchitis and 600-1200 mg/day or more studied for antioxidant support. Its strongest, best-documented roles remain mucus clearance and, clinically, acetaminophen poisoning.
When to take it
Taken with or between meals, often split into two daily doses; consistency matters more than precise timing for antioxidant goals.
Side effects
Generally well tolerated orally; can cause nausea, vomiting, or diarrhea, and has an unpleasant sulfur smell. High doses may rarely affect bleeding or blood pressure.
Sources
Products containing NAC (N-Acetylcysteine)
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