CRN files citizen petition requesting FDA to reverse its policy change on supplements containing N-acetyl-L-cysteine

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The Council for Responsible Nutrition (CRN; Washington, D.C.) has submitted a citizen petition requesting that the U.S. Food and Drug Administration (FDA) reverse its position that the Federal Food, Drug, and Cosmetic Act (FDCA) prohibits manufacturers from marketing products containing N-acetyl-L-cysteine (NAC) as dietary supplements. CRN contends that the policy – which FDA suddenly adopted after decades of permitting manufacturers to market dietary supplements containing NAC – is legally invalid.

FDA asserts in multiple warning letters that products containing NAC cannot be marketed as dietary supplements because it was approved as a new drug in 1963, and there are no records of it being marketed as a dietary supplement prior to that date. CRN argues that it is unclear, based on FDA records, if the drug preclusion clause applies to NAC as a dietary supplement. According to CRN, the records of NAC’s drug approval contain unreliable and conflicting information. Additionally, NAC drugs approved prior to 2016 appear to be comprised of different forms of NAC compared to those found in dietary supplements.

While FDA argues that NAC cannot be marketed as a dietary supplement, the agency has spent decades without objecting to its presence in dietary supplements. “FDA has considered over 100 structure-function claim notifications regarding NAC and at least one qualified health claim petition for a dietary supplement containing NAC, and has not objected to the presence of NAC in any of these products,” writes CRN in its citizen petition. As such, FDA’s newfound interpretation of the law, as it applies to NAC, violates the well-established presumption against statutory retroactivity.

CRN addressed these concerns in a letter to FDA in December of 2020. Cara Welch, PhD, acting director of the Office of Dietary Supplement Programs issued a brief response to CRN in May, stating that FDA is “closely reviewing the information provided in your letter and will provide a more substantive response once our evaluation is complete.” CRN has also had several meetings with FDA leadership, including Welch and acting FDA commissioner Jane Woodcock, in which the issue was raised. Unfortunately, while the Agency says it is considering CRN’s position, it has provided no firm timeline on a substantive response.

The status of NAC as a dietary supplement is urgent because manufacturers are experiencing significant economic impacts. For example, Amazon has removed NAC dietary supplements from its platform. Therefore, CRN took formal action with a citizen petition, which requires FDA to respond within 180 days, and failure to respond may be examined by the courts.