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# Is NAC a Drug or a Dietary Supplement?
- URL: https://www.fdaweb.com/is-nac-a-drug-or-a-dietary-supplement/
- Published: 2020-08-19T12:00:00.000Z
- Updated: 2026-09-14T16:25:35.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5147462

The dietary supplement industry reportedly is concerned about recent Warning Letters to several dietary supplement manufacturers that said N-acetylcysteine (NAC) is excluded from the definition of a dietary supplement because it was first approved as a drug in 1963\. *Natural Products Insider* says in an online [post](https://www.naturalproductsinsider.com/regulatory/fda-warning-letters-nac-cause-stir-supplement-sector?ref=fdaweb.com) that the Warning Letters went to several marketers of supplements for hangover cures.

The post also notes that NAC is included in several research studies as a potential treatment for Covid-19.

According to the post, some 1,170 products containing NAC were listed in the Dietary Supplement Label Database maintained by the National Institutes of Health.

“This is not a fringe ingredient,” Council for Responsible Nutrition CEO **Steve Mister** told the newsletter in an interview. He said that since the Warning Letters were issued, several members of the council have asked whether they should be concerned and whether FDA will be targeting products containing NAC.

FDA Office of Dietary Supplement Programs director **Steven Tave** told *Natural Products Insider* that the letters merely reiterate the agency’s previous conclusions that NAC is excluded from the definition of a supplement. “To the extent that any stakeholders and anyone in industry or anyone else have facts that they think would cause us to rethink our conclusion, then we would welcome that evidence. We’re happy to review it and we would invite them to submit it to us.”