WASHINGTON — The Council for Responsible Nutrition expressed strong disappointment in the U.S. Food and Drug Administration’s decision to deny its citizen petition seeking a clearer framework for interpreting the drug preclusion provision under federal law.
While the agency confirmed that nicotinamide mononucleotide (NMN) is not currently barred from dietary supplement use, the CRN stated that the FDA failed to address the broader regulatory uncertainties that continue to stifle supplement innovation.
“FDA missed a pivotal opportunity to bring clarity and balance to the line between pharmaceuticals and dietary supplements,” said Steve Mister, President & CEO, CRN. “At every juncture where FDA had the opportunity to choose between two interpretations of the statute, it chose one that favors pharmaceutical development over supplements. Consumer access to affordable and accessible healthcare products will be stymied as a result.”
FDA’s Position
In its response to CRN and a parallel industry petition, FDA:
- Confirmed NMN’s current status: FDA clarified that NMN was marketed as a dietary supplement prior to the date that an Investigational New Drug (IND) went into effect, removing any requirement that it had to have been marketed “lawfully.”
- Reaffirmed a secretive “preclusion date”: FDA continues to treat the confidential effective date of an Investigational New Drug (IND) as the operative trigger, rather than when substantial clinical investigations for the article become public—fueling uncertainty for supplement innovators.
- Appears to have broadened “substantial clinical investigations”: The agency response indicates that even early-phase or limited studies can confer drug companies with a monopoly for an ingredient if FDA deems them qualitatively important for drug development. CRN had sought clear delineation from FDA for what constitutes a “substantial” investigation. Basically, FDA claims it will know it when it sees it.
- Limited marketing evidence to the U.S.: FDA rejected foreign marketing of an ingredient as either a food or a supplement as relevant to the race-to-market, even though it puts drug companies on notice of supplement interest in an ingredient. Drug companies may seize on articles marketed elsewhere before they are marketed in the U.S. and prevent their sale as a supplement here.
- Acknowledged one narrow point: “Marketing” need not be “legal” to count—but this technical concession offers little practical relief for most ingredients.
- Declined guidance or rulemaking: FDA again refused to issue interpretive guidance or initiate rulemaking to create reasonable exceptions, citing the need to allocate the agency’s limited resources to “priority matters.”
“The agency’s reliance on non-public IND dates and an expansive view of ‘substantial clinical investigations’ creates a moving target that businesses cannot reliably plan around,” said Megan Olsen, Senior Vice President and General Counsel, CRN. “Yes, FDA now says that NMN is not drug precluded. But the same unstable framework remains in place for the next ingredient, inviting repeat uncertainty.”
Industry Concerns
CRN argued that the FDA’s refusal to reform its interpretation preserves systemic barriers to innovation and consumer access. By keeping IND triggers secret, restricting marketing evidence, and leaving “substantial investigation” undefined, the agency leaves supplement companies vulnerable to sudden restrictions when new dietary ingredients are introduced.
“Collectively, FDA’s response does one thing: it allows FDA to dodge the bullet with respect to NMN and escape a potential legal battle over its status,” Mister added. “But FDA has aggressively declined to provide any real guidance to the supplement or pharmaceutical industries. Without transparent, publicly knowable triggers and workable guidance, companies will continue to face unnecessary conflict with drug development rather than a coherent policy that advances public health.”
Next Steps
CRN urged FDA to revisit its interpretation and provide guidance or for Congress to intervene to ensure dietary supplement access while allowing legitimate drug innovation to proceed.
