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📰Read the full NAC evidence review on GMJ News →Complete clinical article, references and updates on news.gmj.ge. This page is the structured safety summary.⚠ Acetaminophen overdose — NAC is the gold standard antidote (150 mg/kg IV loading). Give within 8 hours of ingestion for maximum benefit, but effective even later [2]
⚠ Patient on nitroglycerin + NAC — potentiation causes severe hypotension and headache [1]
⚠ COPD patient with frequent exacerbations — NAC 600 mg BID may reduce exacerbation frequency [5]
⚠ OCD patient not fully responding to SSRI — NAC 600–1,200 mg BID as adjunct has evidence [7]
⚠ Contrast-induced nephropathy prevention — ACT trial was negative, but some guidelines still recommend NAC + IV saline [6]
ℹ️ Not obtained from food. Not applicable — this is not obtained from food in meaningful amounts; supplementation is the practical route.
🔬 Lab interpreter
Recommended test
No routine monitoring needed for supplementation
No routine monitoring needed for supplementation
Reference range / target
N/A
N/A
For acetaminophen OD: serum acetaminophen level, ALT, AST, INR, creatinine are monitored. For supplement use: no routine labs needed [2].
Full lab monitoring ↓⚕ For professionals — confirm ranges against your local laboratory.
Clinical verdict
NAC is the most efficient glutathione precursor and the acetaminophen overdose antidote. As a mucolytic, it reduces COPD exacerbations. Emerging psychiatric evidence for OCD and compulsive disorders. Oral bioavailability is only 6–10% but sufficient to raise glutathione. Do NOT combine with nitroglycerin (severe hypotension). FDA regulatory status remains in flux [1] [2] [5] [7].
1 How much do I need?
👤 Adults: Specific dosage data under clinical review
👴 Elderly: Specific dosage data under clinical review
🤰 Pregnancy: See guidance
FDA Category B. Used in pregnancy for acetaminophen OD (untreated OD is fatal). As supplement: limited safety data. Consult physician [2].
👦 Pediatric: See guidance
🏃 Athletes: Standard dose
⚖️ Obesity: Standard dose
Fat-soluble compounds may require dose adjustment in obesity.
🩺 Renal: Consult specialist
Dose adjustment may be needed in renal impairment.
🌱 Vegan: Standard dose
How to take
🍽 Timing: Take on an empty stomach for best absorption. If GI upset occurs, can be taken with a small amount of food [1].
💊 With food: Empty stomach preferred. GI-sensitive patients may take with food (modest absorption reduction) [1].
2 Which form?
| Form | Bioavailability | Vegan | Cost |
|---|---|---|---|
| ['NAC oral capsules/tablets', 'common', 'Standard supplemental form. 600–1,200 mg per dose. Low bioavailability (~6–10%) but sufficient to raise glutathione levels [1].'] | Standard | Check label | |
| ['NAC effervescent tablets', '', 'Dissolved in water. Used as mucolytic (200–600 mg TID). Better GI tolerability for some patients [1].'] | Standard | Check label | |
| ['IV N-Acetylcysteine (Acetadote)', '', 'Hospital use only. Acetaminophen overdose protocol. Also used for contrast-induced nephropathy prevention (debated) [2].'] | Standard | Check label | |
| ['NAC nebulized solution', '', 'Inhaled mucolytic for cystic fibrosis and chronic bronchitis. 3–5 mL of 20% solution [1].'] | Standard | Check label |
3 Common questions
Why did the FDA try to ban NAC supplements? ▼
In 2020, the FDA warned supplement companies that NAC was first approved as a drug (1963) before being sold as a supplement, potentially disqualifying it under the DSHEA exclusion clause [3]. After public backlash, the FDA issued guidance in 2022 indicating it would exercise enforcement discretion and allow NAC supplement sales to continue. NAC supplements remain widely available.
Does NAC boost glutathione? ▼
Yes — NAC is the most efficient way to increase intracellular glutathione. L-cysteine is the rate-limiting substrate for glutathione synthesis, and NAC provides cysteine in a stable, absorbable form [1]. Oral NAC (600–1,200 mg/day) significantly increases blood and tissue glutathione levels.
Is NAC the same as taking glutathione supplements? ▼
No — oral glutathione is poorly absorbed (broken down in the GI tract). NAC provides the rate-limiting precursor (cysteine) so that cells can synthesize their own glutathione intracellularly [1]. NAC is generally considered more effective than oral glutathione for raising intracellular GSH levels.
Does NAC help with mental health? ▼
Emerging evidence supports NAC as adjunctive treatment for OCD, trichotillomania, skin picking, and some substance use disorders. A 2015 meta-analysis found benefit for OCD symptoms when added to SSRIs [7]. Results across psychiatric conditions are mixed — it is not a standalone treatment but may be a useful adjunct.
4 Clinical evidence
Strong
Acetaminophen overdose antidote: gold standard treatment since 1977. Prevents hepatotoxicity by replenishing glutathione, which detoxifies NAPQI (the toxic metabolite) [2]. Mucolytic in chronic bronchitis: meta-analyses show reduction in exacerbation frequency with 400–1,200 mg/day [5]. Contrast-induced nephropathy prevention: some guidelines recommend oral NAC + IV saline before contrast procedures, though the ACT trial (n = 2,308) showed no benefit [6]. HIGH
Moderate
Psychiatric applications: emerging evidence for OCD (adjunctive to SSRIs), trichotillomania, skin picking, and substance use disorders (nicotine, cocaine, cannabis) — multiple RCTs with mixed results [7]. COPD: HIACE trial showed 600 mg BID reduced exacerbation frequency [5]. Polycystic ovary syndrome: some evidence for improved ovulation when combined with clomiphene [1]. Idiopathic pulmonary fibrosis: PANTHER-IPF sub-study showed benefit in combination therapy [1]. MODERATE
Insufficient
5 Safety, toxicity & adverse events
Relative
⚠ Asthma — rare bronchospasm reported
⚠ Concurrent nitroglycerin — may potentiate hypotension and headache
⚠ Anticoagulants/antiplatelets — mild additive antiplatelet effect at high doses
🚩 Red flags
● Patient on nitroglycerin experiencing severe headache and hypotension after taking NAC — drug interaction [1]
● IV NAC infusion: flushing, wheezing, rash within minutes — anaphylactoid reaction; pause infusion, give antihistamine [2]
● Patient using NAC as sole treatment for psychiatric condition — it is adjunctive only, not standalone [7]
6 Interactions
Drug interactions
Nitroglycerin (GTN, NTG) Major
Mechanism: NAC potentiates nitroglycerin's vasodilatory effect by maintaining the thiol groups required for nitric oxide release. [1]
Effect: Severe hypotension and headache. Can be dangerous in hemodynamically unstable patients. [1]
Action: Avoid concurrent use of NAC supplements in patients on nitroglycerin therapy [1].
Activated charcoal Major
Mechanism: Charcoal adsorbs NAC in the GI tract, reducing oral bioavailability. [2]
Effect: Reduced NAC efficacy. Relevant in acetaminophen OD management. [2]
Action: If both are needed, use IV NAC instead of oral. If oral NAC is used, separate by at least 1–2 hours [2].
ACE inhibitors (enalapril, lisinopril) Moderate
Mechanism: NAC may potentiate vasodilatory effects through nitric oxide pathway. [1]
Effect: Enhanced blood pressure lowering. Risk of hypotension. [1]
Action: Monitor blood pressure. Usually not clinically significant at standard supplement doses [1].
Carbamazepine Moderate
Mechanism: Case reports of increased carbamazepine levels with NAC co-administration. Mechanism unclear. [1]
Effect: Potential carbamazepine toxicity. [1]
Action: Monitor carbamazepine levels if starting NAC [1].
Supplement synergies
Vitamin C · 500–1,000 mg/day
Vitamin C recycles oxidized glutathione back to reduced form, working synergistically with NAC's glutathione synthesis support [1].
Vitamin C recycles oxidized glutathione back to reduced form, working synergistically with NAC's glutathione synthesis support [1].
Alpha-Lipoic Acid · 300–600 mg/day
ALA regenerates oxidized glutathione (GSSG → 2GSH). Combined with NAC, both synthesis and recycling are enhanced [1].
ALA regenerates oxidized glutathione (GSSG → 2GSH). Combined with NAC, both synthesis and recycling are enhanced [1].
Glycine · 1–3 g/day
Glycine is one of the three amino acids in glutathione (glutamate + cysteine + glycine). NAC provides cysteine; glycine provides the third substrate [1].
Glycine is one of the three amino acids in glutathione (glutamate + cysteine + glycine). NAC provides cysteine; glycine provides the third substrate [1].
7 Regulatory
United States (FDA): Dual status: FDA-approved drug (Mucomyst/Acetadote for acetaminophen OD and mucolytic) AND sold as dietary supplement. FDA enforcement discretion since 2022. No RDA [3].
European Union (EFSA): Available as both pharmaceutical and food supplement. Used extensively as mucolytic (Fluimucil brand) in European clinical practice [1].
Japan (MHLW): Available as dietary supplement and pharmaceutical.
South Korea (MFDS): Available as dietary supplement ingredient.
8 US supplement products
12
on-market products containing NAC (NIH DSLD)
Brands carrying NAC (7)
Click a brand to see its NAC products.
9 Frequently paired with
10 Cite this page
Vancouver: Pkhakadze G. NAC — safety profile [Internet]. Tbilisi: PHIG; 2026 [cited 2026 Sep 01]. Available from: https://supplement.ge/ingredients/nac/
APA 7th: Pkhakadze, G. (2026). NAC — Safety profile. Public Health Institute of Georgia. https://supplement.ge/ingredients/nac/
📋 Editorial information
Author: Prof. G. Pkhakadze, MD, MPH, PhD
Institution: Public Health Institute of Georgia (PHIG)
Affiliation: David Tvildiani Medical University (DTMU)
First published: January 2026
Last reviewed: 2026-05-29
Next review: March 2027
References: 7 cited sources
COI: SupplementIndex receives no funding from supplement manufacturers. All content independently authored by PHIG.
Process: Systematic literature review
📄 License & reuse
Published under Creative Commons Attribution 4.0 International (CC BY 4.0). You may share and adapt for any purpose with attribution.
Pkhakadze G. "NAC — Safety Profile." SupplementIndex, PHIG, 2026. https://supplement.ge/ingredients/nac/ CC BY 4.0.
GP
Prof. G. Pkhakadze, MD, MPH, PhD
Professor of Public Health · Head of Department, DTMU
Editor-in-Chief, Georgian Medical Journal (ISSN 3088-4322)
Chair, Public Health Institute of Georgia · UEMS Public Health Section
Educational and public health purposes. CC BY 4.0. Consult your healthcare provider before starting any supplement. Corrections: info@accreditation.ge. Publisher: PHIG