N-Acetylcysteine (NAC)
Of 1,551 on-market n-acetylcysteine (nac) products in the January 2026 DSLD dump, the median declared dose is 200 mg, and 100.0% list N-Acetyl-L-Cysteine (free-form / USP) as the primary form.
Form share
Of 1,551 products with an identifiable primary form, here is the share held by each form of N-Acetylcysteine (NAC) on the market today.
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| Form | Quality tier | n | Share |
|---|---|---|---|
| N-Acetyl-L-Cysteine (free-form / USP) | Tier 1 | 1,551 | 100.0% |
Form share over time
Entry-year breakdown of the top forms, 2012–2025.
Dose distribution
Deciles of declared dose per serving (mg), among 1,250 products with a disclosed amount.
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- 40.7% of products fall below the fairy-dust threshold (120 mg, 20% of the studied low dose).
- 19.1% of products don't disclose an amount because N-Acetylcysteine (NAC) is declared inside a proprietary blend.
Where does your dose rank?
Enter a per-serving dose (mg) to see exactly how it compares to the 1,250 on-market n-acetylcysteine (nac) products with a disclosed amount. The chart above groups doses into deciles; this looks up the exact percentile for one number.
By dosage form
By target group
Top brands
Search interest over time
How often people search for n-acetylcysteine (nac) on Google, US only, the last 5 years. This is public interest, not DSLD label data — a spike here doesn't necessarily line up with anything on this page, and Google's own index (100 = that term's peak popularity in the chosen window) is relative, not an absolute search-volume count.
Or see this search directly on trends.google.com.
Forms explained
The only form used across essentially the entire NAC clinical trial literature (respiratory, psychiatric, hepatoprotective); "free-form"/"USP" label notes describe purity/manufacturing standard, not a chemically distinct form.
Source: Zheng JP et al. 2014, Lancet Respir Med 2(3):187-94, PMID 24621680
Reference values
- RDA (adult): not established — Semi-synthetic L-cysteine derivative, not itself an essential nutrient; no DRI exists.
- Tolerable Upper Intake Level (adult): not established — No IOM/EFSA regulatory UL. The maximum licensed dose for chronic (mucolytic) use is 600mg/day, but doses of 600mg up to 3000mg/day were used in the 41 studies reviewed for safety in chronic respiratory disease, with an adverse-event profile similar to standard doses (Calverley P, Rogliani P, Papi A. Drug Saf 2021;44(3):273-290, PMID 33326056; a review sponsored by Zambon). Note: NAC's US dietary-supplement status has an unresolved regulatory history (FDA 2022 enforcement-discretion stance) -- a classification dispute, not a safety finding.
- Studied clinical dose range: 600–3000 mg
- The 600-3000mg/day range is that of the studies reviewed by Calverley P et al. 2021 (Drug Saf 44(3):273-290, PMID 33326056); PANTHEON itself tested 1200mg/day. Zheng JP et al. 2014 (PANTHEON trial), Lancet Respir Med 2(3):187-94, PMID 24621680 -- RCT (n=1,006) COPD patients, 600mg BID (1200mg/day) x1yr; significantly fewer exacerbations vs placebo (1.16 vs 1.49/patient-year, RR 0.78, P=0.0011), no significant increase in adverse events.