What works better to raise NAD+: NMN or NR?

NMN and NR perform equally well when it comes to blood levels. In a randomised study of 65 healthy adults, both supplements raised blood NAD+ concentrations to a comparable extent after 14 days. The study was not large enough to demonstrate a clear difference between the two, but both produced an effect. Nicotinamide, a third related compound, did not raise NAD+ over the longer term; it produced only a brief, transient spike.

Interesting is how that NAD+ rise is likely achieved. Both NMN and NR are converted in the gut by intestinal bacteria into nicotinic acid. That converted form turns out to be a potent NAD+ booster in laboratory research, whereas NMN and NR themselves are not, outside the body. This suggests that your gut microbiome partly determines how much benefit you get from these supplements. The composition of your gut flora may therefore be relevant, although this mechanism has not yet been fully clarified in humans.

Whether those higher NAD+ levels in the blood actually lead to better health is a separate question. A review study concludes that NMN and NR are safe, but that the evidence for real health gains, such as more energy, better muscle function, or a sharper memory, remains unclear. The existing human studies are too small and too varied in design to allow firm conclusions.

In the lab, a related compound, NRH, scores clearly better than both NMN and NR: at comparable doses it raised NAD+ in cells and mouse tissue two to ten times more strongly. However, NRH is not an available supplement for humans and this has so far only been demonstrated in cell and mouse research. For the time being, there is no reason for humans to choose one over the other, as direct comparative research between NMN and NR is limited.