Highlights

  • In a letter signed by a representative from the FDA, the agency confirmed that NMN is lawful in supplements.
  • This declaration comes on the heels of the FDA’s declaration in November 2022 that NMN was not allowed as a dietary ingredient due to its prior investigation as a new drug.
  • The FDA’s reversal of its November 2022 announcement raises the question of whether NMN will return for sale from e-commerce vendors like Amazon and other American suppliers.

Once hailed as a promising addition to the repertoire of NAD+ precursors, NMN wound up in a whirlwind of regulatory controversy when the US FDA stated in November 2022 that the compound was excluded from the definition of a dietary supplement. That decision stemmed from a drug exclusion clause, a provision that prevents an ingredient from being marketed as a dietary supplement if it has been the subject of substantial clinical investigations. In NMN’s case, the compound was already the subject of an Investigational New Drug application from the company MetroBiotech, so the FDA argued that marketing it as a supplement was unlawful.

Companies supplying and vending NMN, as well as consumers, felt an immediate and pronounced impact from this decision—NMN disappeared from Amazon US websites and also from vending platforms of many other American suppliers. However, advocacy groups pushed back. For example, the Natural Products Association (NPA) and the Alliance for Natural Health (ANH) filed a joint citizen petition in 2023, requesting that the FDA reverse its decision on NMN.

The FDA Reverses Its Designation of NMN

Now, in response to that petition, Donald Prater, Principal Deputy Director for Human Foods with the FDA, has confirmed a reversal of that decision. This new decision from the FDA makes NMN lawful for use in dietary supplements.

“We now conclude that NMN is not excluded from the definition of dietary supplement under section 201(ff)(3)(B),” stated the FDA in a letter. “Specifically, although NMN was authorized for investigation as a new drug, and substantial clinical investigations of NMN have been instituted and made public, NMN was marketed as a dietary supplement in the United States before such authorization.”

The FDA’s Original Decision Was Not the “Best Reading” of the Statute

The letter from Prater and his colleagues at the FDA also states that the agency’s earlier position was not the best “best reading” of the statute. In other words, the FDA now considers the timing of marketing for a new supplement as a key determinative factor in deciding how to interpret the statute.

The FDA’s updated position, basing whether new supplements can be lawfully used in dietary supplements on whether they were marketed before undergoing investigation as a new drug, marks a shift. In that sense, future vendors may be inclined to rush to market new supplements without first providing evidence of their safety. This may happen more frequently because the sooner vendors market a new supplement, the less likely pharmaceutical companies are to investigate the supplement and make it unlawful for use in dietary supplements.

“FDA’s absurd misinterpretation of the law will not stand for long,” said Carlos Lopez of Niagen, a company that produces a proprietary form of the NAD+ precursor nicotinamide riboside, in a press release. “By effectively green-lighting reckless ‘race-to-market’ behavior, the agency undermines the very safeguards Congress put in place to ensure dietary supplements are safe before reaching consumers. For decades, FDA itself has warned that bad actors ignore premarket notification requirements – requirements that are FDA’s only mechanism to evaluate safety before exposure. Yet this ruling perversely incentivizes more unlawful behavior, increasing the likelihood that unsafe products will flood the market. FDA’s decision is wrong as a matter of both policy and law, and we are confident the agency will be forced to reverse course – either on its own or through litigation.”

Some Industry Leaders Welcome the FDA’s New Decision

While some have issues with the FDA’s new decision, others welcome it. As an example, the NPA, which has long pressed the FDA for a reversal of its first declaration on NMN, greeted the reversal as a victory.

“FDA’s decision today confirms NMN is lawful in supplements, and now we call on e-commerce platforms to immediately restore NMN products to the market,” said President and CEO of NPA, Daniel Fabricant. “We will continue pressing Congress, the courts, and the administration until FDA stops abusing the drug preclusion clause once and for all.”