What the studies show
Oral NR and NMN are well tolerated in trials up to several months. Intravenous NAD+ is a different matter — unstudied in controlled trials and associated with infusion reactions.
Human trials exist and mostly agree, but there are too few of them, they are too small, or one big one is still reading out. Expect the grade to move.
- 1Martens CR, et al. Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD+ in healthy middle-aged and older adults.Nat Commun, 2018;9:128624 adults, crossover; NR raises NAD+, well tolerated.
In context
NAD+ is a coenzyme every cell uses for energy metabolism; it is not a peptide, but its precursors (NMN and NR) and intravenous NAD+ itself are sold across the same anti-ageing market. Randomised trials show the oral precursors reliably raise NAD+ levels and are well tolerated. What they have not yet shown is a clear clinical benefit — trials of metabolism, muscle and ageing are small, mixed and contested. Intravenous NAD+ has essentially no controlled evidence.
NAD+ and precursors is sold as supplement (nr/nmn); iv nad+ unlicensed. Legal status differs by country — see the regulation section or the jurisdiction pages.
Questions
Is NAD+ and precursors proven to cause safety?
What studies are behind the grade?
Is NAD+ and precursors approved for this?
Other outcomes for NAD+ and precursors
- BRaising NAD+ levelsMultiple RCTs (NR, NMN)
- CInsulin sensitivity / metabolic health1 small RCT (n=25), contested
- DAnti-ageing / physical functionNo outcome trials
Written and maintained by LYO Research — how pages are written and checked. Reviewed 3 September 2026. Grades count human evidence only; see how LYO grades. Not medical advice. Correct this page →