NAC · N-Acetylcysteine
Cysteine donor for glutathione synthesis; drug-strength efficacy for specific uses.
Short answer
NAC (N-Acetylcysteine) is a glutathione precursor with evidence grade B, meaning it is supported by human RCTs. We track 6 produkter containing NAC. Typical doses range from 10.0 to 900.0 mg per portion. The top-ranked product scores 7.4 out of 10 on our composite scale (dose, evidence, price, testing, transparency). Prices range up to $101.00 per månad.
Top NAC produkter
| Product | Varumärke | Dose | Pris/mo | 3rd-party tested | Poäng |
|---|---|---|---|---|---|
| N-Acetyl L-Cysteine (NAC) Powder | 600.0 mg | $20.97 | No | 7.4 | |
| Jarrow Formulas N-A-C Sustain, 600 mg | 600.0 mg | $25.99 | No | 7.4 | |
| NAC - N-Acetylcysteine (Cysteplus) | 500.0 mg | $29.00 | Yes | 7.2 | |
| NAC (N-Acetyl-L-Cysteine) 900 mg | 900.0 mg | $101.00 | No | 6.7 | |
| Glycine & NAC | 300.0 mg | $30.00 | Yes | 6.0 |
Scores are editorial judgments, not a scientific standard. Se how we score.
What it is
A form of cysteine (an amino acid) that your body converts into glutathione, your master antioxidant. Used medically for paracetamol overdose and lung mucus clearance.
Why people take it
Restores glutathione reliably. Real benefits in COPD, chronic bronchitis, and glutathione depletion in older adults (especially with glycine). Longevity benefits inferred from oxidative-stress mechanism, not directly tested.
Our verdict
Solid, cheap, well-studied. FDA occasionally hassles supplement sellers about NAC being a 'drug', but availability continues.
Structure & class
N-acetyl-L-cysteine. Deacetylated to cysteine, condensed with glutamate and glycine to form GSH.
Mechanism & clinical data
Multiple trials show restoration of hepatic and RBC glutathione. Kumar 2021 (GlyNAC) demonstrated broad aging biomarker improvements at 800 mg NAC + 3.6 g glycine per dag.
Pharmacokinetics
~6 hours.
Dose & forms
What to watch out for
Smells like sulfur (rotten eggs). Enteric-coated forms reduce this. Don't combine with nitrates without medical supervision.
Where this dose comes from
The trial dose above is our editorial pick from the published human trials for this ingredient. We choose the dose that the best-available studies used on the endpoint most relevant to longevity. The range shows the lowest and highest doses tested in published trials. The landmark studies below are the papers we read to set it. You can click through and check our work.
When new trials publish, our automated sweeps flag them. If a new study materially changes the dose, we update it through editorial review and record the old dose, new dose, and the triggering study in every affected product's recommendation history. The dose is never changed automatically.
Regelverk status
Timeline
Regelverk events, evidence grade changes, and key research milestones for NAC, most recent first. Every entry links to its primär source.
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EU Court sharpens the bar for botanical health claimsA Court of Justice of the European Union ruling in april 2025 further tightened the requirements for how botanical ingredients (herbs, plant extracts) can be marketed with health claims in the EU, effectively removing much of the flexibility of the on-hold list.
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EU report identifies 117 supplement substances as potential health risksThe HoA Working Group on Food Supplements (26 European countries) published its first report evaluating 117 substances used in food supplements. Of these, 65 were assessed as likely novel foods, 6 were already regulated, 34 had insufficient data, and 12 were prioritized for Article 8 restriction under Regulation (EC) No 1925/2006. The 12 priority substances include ashwagandha, curcumin, melatonin, piperine, St. John's wort, coumarin, p-synephrine, maca, holy basil, Melaleuca, black cohosh, and L-tryptophan. The report drew on 1,500 RASFF alerts reviewed between 2017 and mid-2022.
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FDA issues final guidance: enforcement discretion for NAC supplementsThe FDA issued final guidance (FDA-2022-D-0490) announcing its intent to exercise enforcement discretion with respect to the sale and distribution of certain NAC-containing produkter labeled as dietary supplements. This reversed the de facto ban from the 2020 warning letters. Amazon resumed sales of NAC produkter. The legal status remains ambiguous: NAC is technically excluded from the supplement definition, but the FDA chooses not to enforce against compliant produkter.
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Kumar et al. 2021 (Clin Transl Med)GlyNAC for 24 weeks improved glutathione, inflammation, insulin resistance.
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FDA sends warning letters declaring NAC excluded from supplement definitionThe FDA sent warning letters to seven companies selling NAC-containing hangover produkter, declaring that NAC is excluded from the dietary supplement definition under 21 U.S.C. 321(ff)(3)(B)(i) because it was first approved as a new drug in september 1963. Amazon subsequently removed NAC produkter from its marketplace. The FDA stated it was unaware of any evidence that NAC was marketed as a dietary supplement or food before the drug approval.
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EU Health Claims Regulation adoptedRegulation (EC) No 1924/2006 laid down harmonised rules for nutrition and health claims made on foods, including supplements. Only claims listed in the EU Register of authorised claims can be used. Rejected botanical claims are held in a separate on-hold list.
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EU introduces the Novel Food RegulationRegulation (EC) No 258/97 required any food or food ingredient without a history of consumption in the EU before 15 maj 1997 to be authorised before being placed on the market. This is the framework that captures NMN, spermidine as a supplement ingredient, urolithin A, and many other longevity actives.
NAC has a modest, real effect on depression symptoms as an add-on treatment across 12 pooled RCTs, but its benefit in bipolar disorder and major depression alone is small and inconsistent.
Verified 2026-07-14. We update this section as new peer-reviewed trials land.
Best-supported claim
NAC's clearest psychiatric evidence is as an add-on treatment for depression symptoms, not a standalone cure. Zhang et al.'s 2024 metaanalys of 12 RCTs and 904 depressed patients found adjunctive NAC at 1,000-3,000 mg/day for 8-24 weeks significantly improved depression scores versus placebo (SMD -0.24, 95% CI -0.44 to -0.05, P=.02) (https://pubmed.ncbi.nlm.nih.gov/39504621/). NAC is also an established, FDA-approved antidote for acetaminophen overdose and has decades of safety data in that clinical use, giving it a strong pharmacological safety track record outside the psychiatric context.
Not supported by the evidence base
NAC is marketed as a broad mental-health and mood supplement effective across depression, bipolar disorder, and general anxiety, but a 2018 metaanalys of 6 RCTs and 701 patients found adjunctive NAC was efficacious for schizophrenia (SMD -0.74) yet showed no significant effect on depressive or manic symptoms in bipolar disorder and only a small effect on major depressive disorder alone (https://onlinelibrary.wiley.com/doi/abs/10.1111/acps.12862). Marketing for NAC as a hangover cure or general liver detox supplement also outruns current evidence: while a 28-day pilot trial found NAC feasible and safe for alcohol use disorder with some improvement in consumption measures, the larger confirmatory multi-site trial was still recruiting as of its 2025 protocol publication, so definitive efficacy for alcohol-related outcomes is not yet established (https://pmc.ncbi.nlm.nih.gov/articles/PMC12421191/).
Typical dose
1,000-3,000 mg/day for psychiatric adjunctive use, split into two doses; 2,400 mg/day used in alcohol use disorder trials
Säkerhet
NAC has shown a safety profile similar to placebo across psychiatric RCTs, with the 2018 major mental disorders metaanalys reporting adverse drug reactions and discontinuation rates comparable between NAC and control groups (https://onlinelibrary.wiley.com/doi/abs/10.1111/acps.12862). Mild gastrointestinal upset, including nausea and reflux, is the most commonly reported side effect. NAC is well established as safe at high intravenous doses for acetaminophen overdose treatment under medical supervision. Personer with asthma should use oral NAC cautiously since inhaled forms have triggered bronchospasm in some individuals, though this is a different route of administration than oral supplements.
Interactions worth flagging
- Can enhance the effect of nitroglycerin, potentially causing severe headache or hypotension
- maj increase bleeding risk when combined with anticoagulants due to mild antiplatelet activity
- Could theoretically reduce the efficacy of activated charcoal treatments if taken together in overdose settings
Three recent studies to know
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Efficacy of N-acetylcysteine for patients with depression: a systematisk översikt and metaanalys
Meta-analysis of 12 RCTs found adjunctive NAC significantly improved depression scores versus placebo, with a modest effect size, particularly in bipolar disorder.
Läs studie → -
N-acetyl cysteine for the treatment of alcohol use disorder: study protocol for a multi-site, dubbelblind randomised controlled trial (NAC-AUD study)
A multi-site RCT protocol describes testing 2,400 mg/day NAC for 12 weeks in alcohol use disorder, following an earlier 28-day pilot that found NAC feasible, safe, and associated with some improvement in drinking measures.
Läs studie → -
A Randomized Controlled Trial of N-acetylcysteine for Adolescent and Young Adult Alcohol Use Disorder
A fully powered 8-week RCT in youth aged 15-25 found NAC 2,400 mg/day showed no overall benefit over placebo for alcohol use disorder, but significantly reduced drinking in the subgroup with moderate to severe disorder.
Läs studie →
Landmark studies
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Kumar et al. 2021 (Clin Transl Med)
GlyNAC for 24 weeks improved glutathione, inflammation, insulin resistance.
Läs studie →
Found in these produkter (6)
Alla produkter in our catalog that contain NAC, ranked by our overall score. Ranking is editorial, never paid.
Buying guides and comparisons
Related ingredients
Se alla in Glutathione precursor →Molekyler in the same class, plus the actives most often formulated alongside NAC in our catalogue.
Frequently asked questions
What is NAC?
A form of cysteine (an amino acid) that your body converts into glutathione, your master antioxidant. Used medically for paracetamol overdose and lung mucus clearance.
What dose of NAC should I take?
The trial dose in published human studies is 600 mg per dag, with a range of 600 to 1800 mg per dag. Always consult a qualified clinician before starting any supplement.
Is NAC safe?
Smells like sulfur (rotten eggs). Enteric-coated forms reduce this. Don't combine with nitrates without medical supervision.
What is the best NAC supplement?
We track 6 produkter containing NAC. The top-ranked product scores 7.4 out of 10 on our composite scale, which evaluates dose, evidence, price, third-party testing, and transparency. See the comparison table above. Scores are editorial judgments, not a scientific standard.
What is the evidence grade for NAC?
NAC has evidence grade B, meaning it is supported by human RCTs. Grade A means replicated human RCTs with hard endpoints. Grade B means human RCTs with biomarker outcomes. Grade C means mixed or small human trials. See our evidence grading methodology.
Data verification
Bevisning grades are reviewed when new human RCTs are published. Product counts update automatically as new produkter are added. Dose ranges reflect published trial data, not brand recommendations. Read how we verify.