NAC
Precursor to glutathione, a major antioxidant in the body.
Also known as N-Acetyl Cysteine, N-Acetylcysteine
Common doses
600-1800 mg
Best timing
Morning
Food
Take on an empty stomach
Interactions
5 known
N-Acetylcysteine (NAC) is a derivative of the amino acid L-cysteine and the most efficient oral precursor to glutathione, the body's master antioxidant. Cysteine is the rate-limiting amino acid in glutathione synthesis, making NAC supplementation a direct way to boost glutathione levels.
NAC has a remarkably diverse range of clinical applications. It is a licensed medication for acetaminophen (paracetamol) poisoning and is used as a mucolytic in respiratory conditions. As a supplement, it is studied for liver support, mental health (OCD, addiction, mood disorders), respiratory health, and detoxification.
NAC also modulates glutamate signalling via the cystine-glutamate antiporter, which is the basis for its emerging role in psychiatric conditions. This glutamate-modulating effect is distinct from its antioxidant role.
Key benefits
Glutathione production
NAC is the most effective oral supplement for raising glutathione levels. Glutathione is the body's primary intracellular antioxidant and detoxification molecule.
Liver support
NAC supports liver detoxification and is the clinical treatment for acetaminophen overdose. It replenishes hepatic glutathione.
Respiratory health
NAC is a mucolytic that breaks down mucus. It is used clinically for chronic bronchitis and COPD to reduce exacerbation frequency.
Mental health
Emerging evidence for NAC in OCD, addiction, and mood disorders through glutamate modulation and oxidative stress reduction.
Available forms
NAC (Standard)
The most common form. Well-absorbed orally. Typical dose is 600-1,800 mg/day, split into 2-3 doses. Can have a sulfurous smell.
Sustained-Release NAC
Extended release formulation. May provide more consistent glutathione support throughout the day.
Food sources
- Not directly found in food (it is a modified amino acid). Cysteine-rich foods support similar pathways: eggs, garlic, onions, cruciferous vegetables, whey protein.
Upper intake limit
No established upper limit from NIH. Clinical doses up to 2,400 mg/day are used. High doses may cause GI upset. NAC may interact with nitroglycerin and blood thinners.
Research summary
Strong evidence for acetaminophen toxicity treatment and mucolytic action. Good evidence for glutathione replenishment. Moderate evidence for COPD exacerbation reduction. Emerging evidence for mental health applications (OCD, trichotillomania, substance use disorders). NAC has one of the broadest evidence bases of any supplement.
Known interactions (5)
Check your full stack
for interactions.
See what competes, what combines well, and when to take everything. Every interaction cites a published source.
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6 supplements
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1 flagZinc and Iron compete for the same absorption pathway. Take at least 2 hours apart.
Supplements
This information is for educational purposes only. It is not medical advice and does not diagnose, treat, cure, or prevent any disease. Always consult a qualified healthcare professional.