N-Acetyl Cysteine (NAC) — Mechanism, Benefits, Dosing

Overview

Acetylated form of L-cysteine; FDA-approved antidote for acetaminophen overdose.

Natural sources

Synthesized from cysteine

Common forms

NAC
Liposomal NAC

Mechanism of action

Provides cysteine for glutathione synthesis; modulates glutamate via cystine-glutamate antiporter.

Pathways

· GSH synthesis
· Glutamate modulation

Effects on the body

Increases

Glutathione

Supports

Hepatocyte protection

Decreases

Compulsive behaviors

Organ system effects

Liver

Standard antidote for acetaminophen toxicity.

Brain & CNS

Reduces compulsive symptoms in OCD/trichotillomania.

Evidence-based benefits

Reduces acetaminophen-induced hepatotoxicity

Strong evidence

Improves symptoms of trichotillomania / OCD

Moderate evidence

Improves PCOS insulin sensitivity & ovulation

Moderate evidence

Potential side effects

Common

· GI upset
· Sulfur-like odor

Rare

· Headache

Serious

· Rare allergic reaction (IV)

Drug interactions

Nitroglycerin

Potentiates hypotension.

moderate

Safety & non-supplemental interactions

Educational summary — always confirm with your clinician or pharmacist before starting, stopping, or combining with prescription therapy.

Avoid with these conditions

·Autoimmune disease (theoretical immune activation)
·Asthma (rare bronchospasm with inhaled form)
·Active GI bleeding

Avoid / monitor with these medications

·Immunosuppressants
·Nitroglycerin (severe hypotension, headache)
·Activated charcoal (bound and inactivated)

Supplement interactions

Pairs well with

Glycine
Both rate-limiting for GSH synthesis.

Avoid combining with

No specific avoidances listed.

Dosing & bioavailability

Typical dose

600–1800 mg/d (divided)

Timing

Empty stomach if tolerated, else with food

With food?

Either

Where to buy

Affiliate-style search links to reputable retailers. We don't endorse specific brands — verify third-party testing (USP, NSF, Informed Sport) before purchase.

Amino Acid

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Global delivery · curated brands

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Thorne

Practitioner-grade · NSF tested

Scientific evidence (10)

Systematic reviewNeurosci Biobehav Rev · 2015

NAC for psychiatric disorders

Deepmala, et al.

Review of NAC across psychiatric conditions.

Key findings

Evidence supports use in trichotillomania, OCD, and as adjunct in depression.

Open study

Systematic reviewPubMed (NLM) · 1970

PubMed: N-Acetyl Cysteine (NAC) — Reduces acetaminophen-induced hepatotoxicity

Live PubMed search

Live results for "N-Acetyl Cysteine (NAC) Reduces acetaminophen-induced hepatotoxicity" across the PubMed/MEDLINE peer-reviewed index.

Key findings

Opens current human and preclinical literature matching N-Acetyl Cysteine (NAC) and "Reduces acetaminophen-induced hepatotoxicity". Filter by RCT, meta-analysis, or year on the results page.

Open study

Systematic reviewPubMed (NLM) · 1970

PubMed: N-Acetyl Cysteine (NAC) — Improves symptoms of trichotillomania / OCD

Live PubMed search

Live results for "N-Acetyl Cysteine (NAC) Improves symptoms of trichotillomania / OCD" across the PubMed/MEDLINE peer-reviewed index.

Key findings

Opens current human and preclinical literature matching N-Acetyl Cysteine (NAC) and "Improves symptoms of trichotillomania / OCD". Filter by RCT, meta-analysis, or year on the results page.

Open study

Systematic reviewPubMed (NLM) · 1970

PubMed: N-Acetyl Cysteine (NAC) — Improves PCOS insulin sensitivity & ovulation

Live PubMed search

Live results for "N-Acetyl Cysteine (NAC) Improves PCOS insulin sensitivity & ovulation" across the PubMed/MEDLINE peer-reviewed index.

Key findings

Opens current human and preclinical literature matching N-Acetyl Cysteine (NAC) and "Improves PCOS insulin sensitivity & ovulation". Filter by RCT, meta-analysis, or year on the results page.

Open study

Systematic reviewPubMed (NLM) · 1970

PubMed: N-Acetyl Cysteine (NAC) — randomized controlled trial

Live PubMed search

Live results for "N-Acetyl Cysteine (NAC) randomized controlled trial" across the PubMed/MEDLINE peer-reviewed index.

Key findings

Opens current human and preclinical literature matching N-Acetyl Cysteine (NAC) and "randomized controlled trial". Filter by RCT, meta-analysis, or year on the results page.

Open study

Systematic reviewPubMed (NLM) · 1970

PubMed: N-Acetyl Cysteine (NAC) — meta-analysis

Live PubMed search

Live results for "N-Acetyl Cysteine (NAC) meta-analysis" across the PubMed/MEDLINE peer-reviewed index.

Key findings

Opens current human and preclinical literature matching N-Acetyl Cysteine (NAC) and "meta-analysis". Filter by RCT, meta-analysis, or year on the results page.

Open study

Systematic reviewPubMed (NLM) · 1970

PubMed: N-Acetyl Cysteine (NAC) — pharmacokinetics

Live PubMed search

Live results for "N-Acetyl Cysteine (NAC) pharmacokinetics" across the PubMed/MEDLINE peer-reviewed index.

Key findings

Opens current human and preclinical literature matching N-Acetyl Cysteine (NAC) and "pharmacokinetics". Filter by RCT, meta-analysis, or year on the results page.

Open study

Systematic reviewPubMed (NLM) · 1970

PubMed: N-Acetyl Cysteine (NAC) — safety adverse events

Live PubMed search

Live results for "N-Acetyl Cysteine (NAC) safety adverse events" across the PubMed/MEDLINE peer-reviewed index.

Key findings

Opens current human and preclinical literature matching N-Acetyl Cysteine (NAC) and "safety adverse events". Filter by RCT, meta-analysis, or year on the results page.

Open study

Systematic reviewPubMed (NLM) · 1970

PubMed: N-Acetyl Cysteine (NAC) — dose response

Live PubMed search

Live results for "N-Acetyl Cysteine (NAC) dose response" across the PubMed/MEDLINE peer-reviewed index.

Key findings

Opens current human and preclinical literature matching N-Acetyl Cysteine (NAC) and "dose response". Filter by RCT, meta-analysis, or year on the results page.

Open study

Systematic reviewGoogle Scholar · 1970

Google Scholar: N-Acetyl Cysteine (NAC) — clinical evidence

Live Scholar search

Cross-database citation index for N-Acetyl Cysteine (NAC) as it relates to "clinical evidence".

Key findings

Includes preprints, theses, and journal articles. Useful for tracking citation counts and follow-on work.

Open study

Educational use only. This profile is not medical advice. Consult a qualified healthcare professional before starting any supplement, especially if you take prescription medication or have a chronic condition.