The FDA's Reclassification and the 'Drug Preclusion' Clause
For several years, NMN, a precursor to the vital coenzyme NAD+, was sold in the US as a dietary supplement. Interest was driven by research suggesting its potential role in cellular energy and healthy aging. However, in late 2022, the U.S. Food and Drug Administration (FDA) dramatically changed its position, determining that NMN could no longer be marketed as a dietary supplement.
This decision stemmed from the “drug preclusion” clause of the Federal Food, Drug, and Cosmetic Act. This clause states that if an ingredient is first investigated as a new drug before it is marketed as a supplement, it cannot be sold in supplement form. The FDA concluded that NMN was being investigated as a new drug (specifically, a proprietary version known as MIB-626 by Metro International Biotech) before it met the criteria for supplement marketing.
It is critical to note that the FDA’s ruling was based on a regulatory technicality, not on any evidence that NMN is unsafe for consumption. This distinction is at the heart of the ongoing controversy surrounding the compound's status.
The Industry Fights Back: Legal Challenges and an Enforcement Pause
In response to the FDA's reversal, the dietary supplement industry mobilized to challenge the decision. Trade organizations, including the Natural Products Association (NPA) and the Alliance for Natural Health (ANH), submitted citizen petitions and ultimately filed a federal lawsuit against the FDA. Their argument centered on the claim that the drug preclusion clause was being misapplied and that NMN had a history of lawful marketing as a supplement prior to the drug investigation.
This legal pressure led to a significant development in late 2024. A federal court approved a joint motion to stay the lawsuit, and the FDA announced it would temporarily pause enforcement of its 2022 decision. This pause allows companies to continue selling NMN without fear of immediate regulatory action while the FDA reviews the petitions. The FDA's final decision has been delayed several times, with the most recent timeline extending to September 30, 2025. This means that while NMN is technically in a regulatory gray area, its sale is not actively being prevented by the FDA.
Navigating the Market and Looking Ahead
Given the regulatory volatility, the NMN market has been significantly disrupted. Following the FDA's initial reclassification, major retailers like Amazon and Walmart delisted NMN products from their US platforms. This pushed consumers toward alternative purchasing channels. Today, NMN can primarily be sourced through:
- Direct-to-consumer websites: Many specialized supplement companies continue to sell NMN directly from their own online stores, often emphasizing their quality controls and third-party testing.
- Specialty health retailers: Some niche online retailers and brick-and-mortar health food stores may still carry NMN, though availability is more limited than before the retail bans.
- International vendors: Some US consumers purchase NMN from international suppliers, though this can involve higher shipping costs and potential customs considerations.
When purchasing NMN, prioritizing quality is paramount, especially since the market is not under the same level of dietary supplement regulation it once was. Look for brands that offer Certificates of Analysis (COAs) from independent, third-party labs to verify the product's purity and potency.
A Comparison of NAD+ Boosters
For those seeking NAD+ boosting alternatives, Nicotinamide Riboside (NR) remains a prominent option. The table below compares NMN with NR and Niacin (Vitamin B3).
| Feature | NMN (Nicotinamide Mononucleotide) | NR (Nicotinamide Riboside) | Niacin (Vitamin B3) |
|---|---|---|---|
| Regulatory Status (US) | Currently in a regulatory gray area; sale is allowed under a temporary enforcement pause. | Legally available as a dietary supplement. | Widely available as a standard vitamin supplement. |
| Effectiveness as NAD+ Precursor | Highly effective in boosting NAD+ levels, as shown in numerous studies. | Also effective, and legally recognized as a supplement. | An older and more affordable way to support NAD+, but less direct. |
| Availability | Available from specialty brands and direct-to-consumer websites. | Widely available from many supplement brands, including major retailers. | Readily available at most drugstores and supermarkets. |
| Purity and Quality Control | Requires careful vetting of third-party tested brands due to regulatory uncertainty. | Typically more regulated and found from established brands. | Consistent quality and regulated as a vitamin. |
| Potential Side Effects | Generally considered safe at standard doses, with mild gastrointestinal effects possible. | May cause more side effects than NMN in some studies. | Higher doses can cause flushing. |
Conclusion
Yes, you can still buy NMN in the USA, but navigating the market requires caution due to its uncertain regulatory status. The FDA’s decision to exclude NMN from its dietary supplement category, based on a drug investigation and not safety concerns, has created a legal limbo that continues into 2025. While major retailers have removed NMN, it remains available through other online channels thanks to a temporary FDA enforcement pause. Consumers must focus on purchasing from reputable brands that provide third-party testing to ensure product quality. As the FDA's final decision is still pending, the future of NMN's accessibility as a supplement hangs in the balance, a situation that may ultimately redefine parts of the broader dietary supplement industry.
