CRN submits supplemental comments to 2023 citizen petition urging FDA to “reconsider” its position on drug preclusion

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On March 9, 2025, The Council for Responsible Nutrition (CRN; Washington, D.C.) submitted supplemental comments to its May 9, 2023 citizen petition. That citizen petition asked the U.S. Food and Drug Administration (FDA) to “reconsider” the way it invokes the drug preclusion clause of the Food Drugs and Cosmetic Act (FD&C Act). The petition was in response to how FDA applied the drug preclusion clause to ingredients like n-acetyl-L-cysteine (NAC) and beta-nicotinamide mononucleotide (NMN). In the case of NMN, the agency had to actually retroactively reject a previously accepted new dietary ingredient notification for an NMN product.

The agency has not yet addressed the concerns expressed in CRN’s original submission, instead issuing an interim response where it merely informed CRN that I was unable to respond within the 180-day window, but was still evaluating the petition. In the supplemental submission CRN urged FDA to reexamine and correct its interpretation of the drug preclusion clause rather than provide justification for its interpretation. CRN asserts that the proper interpretation of the clause should align with its original purpose: to properly balance the interests of pharmaceutical and dietary supplement stakeholders. Instead, CRN argues that FDA’s current interpretation essentially permits pharmaceutical manufacturers to obtain perpetual monopolies over substances that would otherwise meet the FD&C Act definition for a dietary supplement, which stifles innovation in that space.

CRN also urged FDA to not consider enforcement discretion a satisfactory resolution of the drug preclusion interpretation issue as it did with NAC as it does not provide any predictability and there remains uncertainty about NAC’s legal status. “The drug preclusion matter will be solved only with a clear roadmap from FDA on how it interprets section 201(ff)(3)(B) going forward—or a legislative solution to amend the law if FDA fails to provide that clarity,” wrote CRN.