NMN (Nicotinamide mononucleotide)

NMN is a nucleotide and NAD+ precursor in the salvage pathway, feeding into a coenzyme central to energy metabolism, sirtuin activity, and DNA repair. Oral NMN is absorbed and raises blood NAD+ in humans, but evidence for clinical longevity benefits remains limited. Trials report modest improvements on specific endpoints such as the 6-minute walk test, muscle insulin sensitivity, or grip strength; large, long-term outcome studies are lacking. NMN's US dietary supplement status was contested from 2022 to 2025, when the FDA reversed its earlier drug-exclusion ruling and confirmed that NMN may lawfully be marketed as a dietary supplement; regulatory status in the EU and other regions varies.