N-Acetyl Cysteine

amino acids

★★★★★

N-Acetyl Cysteine (NAC) is a stable, acetylated form of the amino acid L-cysteine. It serves as a precursor to glutathione, one of the body's most potent antioxidants, and supports respiratory health, detoxification, and immune function.

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Benefits

✓Boosts glutathione production and antioxidant defence

✓Supports respiratory health and mucolytic function

✓Enhances immune system response

✓Promotes liver detoxification and hepatoprotection

✓Supports brain health and mental wellbeing

Dosage

Typical Dose

600–1200 mg daily

Upper Limit

2000–3000 mg daily

Timing

Take with food or water; divided doses are optimal for absorption

Forms & Bioavailability

NAC powder

High (30–60%)

NAC capsules

High (30–60%)

NAC tablets

Moderate–high (25–50%)

Side Effects

⚠Nausea, diarrhoea, and gastrointestinal discomfort at higher doses

⚠Unpleasant sulphur-like body odour and taste

Interactions

⚡May reduce efficacy of certain antibiotics (e.g., amoxicillin) if taken simultaneously

⚡Potential interaction with nitroglycerin and other nitrates; monitor blood pressure

⚡May increase absorption of heavy metals in sensitive individuals

Research Summary

NAC has robust clinical support for acute paracetamol overdose and chronic bronchitis. Evidence supports its role in glutathione synthesis, immune enhancement, and psychiatric conditions (OCD, trichotillomania). Limited but promising research exists for fertility, lung health, and COVID-19 recovery. Generally recognised as safe by regulatory bodies.

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The Bottom Line on N-Acetyl Cysteine

N-Acetyl Cysteine is well-researched with strong evidence supporting its primary benefits.It is most commonly used for boosts glutathione production and antioxidant defence and supports respiratory health and mucolytic function. As with any supplement, individual results vary. Start with the lower end of the dosage range and assess for 4-8 weeks before adjusting.

About Our Research

This profile is compiled from peer-reviewed research published on PubMed, the NIH Office of Dietary Supplements, and established nutritional science databases. Dosages reflect clinically-studied amounts from human trials where available. We update profiles as new research emerges. This is not medical advice — consult a healthcare professional before supplementing.

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Disclaimer: This information is for educational purposes only and is not medical advice. Always consult a healthcare professional before starting any supplement, especially if you have existing health conditions or take medication.