NMN (nicotinamide mononucleotide) is a direct precursor to NAD+ — the coenzyme every cell in your body uses to convert food into energy, repair DNA, and activate longevity pathways like sirtuins. NAD+ levels fall by roughly 50% between age 40 and 60, and that decline is now linked to mitochondrial dysfunction, metabolic disease, and accelerated biological aging. Restoring NAD+ via NMN supplementation, NR (nicotinamide riboside), or IV therapy is one of the most actively researched interventions in human longevity science.

NMN or NR — which should I take?

Both are precursors to NAD+ with strong human safety data. NR has more human clinical trials and is the only NAD+ precursor with FDA NDI status. NMN is one biochemical step closer to NAD+ but its FDA status is contested. For most people the choice comes down to price, format, and brand trust — see our Best NMN of 2026 and Best NR of 2026 rankings.

Do I need to take TMG with NMN?

Probably yes if you take >500 mg/day. NAD+ recycling consumes methyl groups, and chronic high-dose NMN without methyl support may elevate homocysteine in some people. See the NMN + TMG stack guide.