NAC (N-Acetyl Cysteine)

Also known as: NAC, n-acetylcysteine, N-acetyl-L-cysteine

Grade B — Moderate Evidenceamino acidantioxidant

Recommended Dosage

600–1800 mg

With food, split doses

N-Acetyl Cysteine (NAC) is the supplemental form of the amino acid cysteine and serves as the rate-limiting precursor to glutathione — often called the body's "master antioxidant." Used clinically for decades as a treatment for acetaminophen overdose and as a mucolytic, NAC has gained attention for its broad therapeutic potential including respiratory health, psychiatric conditions, liver support, and fertility.

TL;DR: Precursor to glutathione (master antioxidant). Strong evidence for respiratory health, liver support, and psychiatric conditions.

🛡️Immunity🧬Longevity😊Mood🦠Gut Health
Last reviewed: 2026-03-09

Evidence Rating: Grade B — Moderate Evidence

Some RCTs with positive results, or strong observational evidence. More research may refine our understanding.

Forms Comparison

NAC (Standard)

~ Moderate Absorption

The standard oral form. Well-absorbed on empty stomach. The most studied form.

general antioxidantrespiratorypsychiatric

Liposomal NAC

✓ High Absorption

Encapsulated in liposomes for potentially better absorption and reduced GI effects.

GI-sensitive individuals

Interaction Warnings

NitroglycerinHigh Risk

Can cause severe hypotension when combined

Activated charcoalModerate

Charcoal may reduce NAC absorption

Chemotherapy (doxorubicin, cisplatin)Moderate

Antioxidant may theoretically reduce cytotoxic efficacy; consult oncologist

⚠️ Important Notes

  • Glutathione precursor — the master antioxidant
  • GI side effects at high doses
  • Sulfurous odor in effervescent forms

Clinical Evidence (3 studies)

NAC reduced influenza-like illness in elderly

De Flora S et al. (1997) — Eur Respir J

NAC 600mg BID for 6 months reduced influenza-like illness from 42% to 13%

View on PubMed

N-acetylcysteine in psychiatry: current therapeutic evidence

Deepmala et al. (2015) — J Clin Psychiatry

Benefits across depression, bipolar, OCD, and addiction

View on PubMed

NAC for COPD and chronic bronchitis

Ooi SL et al. (2018) — J Altern Complement Med

Systematic review: consistent reduction in exacerbations

View on PubMed

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Grade A — Strong Evidence

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Curcumin

Grade B — Moderate Evidence

Potent anti-inflammatory from turmeric. Must enhance bioavailability with piperine or specialized formulations.

Probiotics

Grade B — Moderate Evidence

Beneficial bacteria for gut health. Strain selection matters — L. rhamnosus GG, B. infantis 35624, and S. boulardii are best-studied.

Sulforaphane

Grade B — Moderate Evidence

Powerful Nrf2 activator from cruciferous vegetables. Evidence for air pollution detoxification and H. pylori eradication.

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⚕️ Important Disclaimer

This information is for educational purposes only. It is not medical advice. Always consult a healthcare provider before starting any supplement regimen, especially if you take medications or have health conditions.

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