Nicotinamide Riboside vs NMN: Which NAD+ Precursor Should You Take?

If you have shopped for an NAD+ supplement, you have seen two acronyms: NR (nicotinamide riboside) and NMN (nicotinamide mononucleotide). Both are vitamin B3 derivatives, both end up as NAD+ inside the cell, and both have human data. They are not interchangeable.

How they differ chemically

NMN is NR with a phosphate group attached. Because of that phosphate, NMN is larger and charged, and most evidence suggests it has to be converted to NR (or transported by a specialized carrier) before it enters cells. NR is one step closer to the cell and is taken up directly, then converted to NMN and finally NAD+ by the NRK enzymes.

Human evidence

NR has the larger body of controlled human trials. Trammell 2016 (single-dose pharmacokinetics), Martens 2018 (six weeks, ~60% increase in blood NAD+), Dollerup 2018 (12 weeks, 2,000mg/day in obese men, well tolerated), Elhassan 2019 (skeletal-muscle NAD+ metabolome in older adults) and Conze 2019 (an eight-week safety study at up to 1,000mg/day) all used NR.

NMN has a smaller but growing set: Yoshino 2021 reported improved muscle insulin sensitivity in prediabetic women after 10 weeks at 250mg/day; Yi 2023 found dose-dependent NAD+ increases at 300–900mg/day over 60 days.

Regulatory status

NR has GRAS (Generally Recognized as Safe) status in the US and a New Dietary Ingredient notification on file with the FDA. NMN's status has been contested: in late 2022 the FDA stated NMN was excluded from the dietary-supplement definition because it had been investigated as a drug, and its availability has fluctuated since. For a company that wants to be on shelves in five years, that matters.

Dose and cost

Most human NR studies used 250–1,000mg per day. Most NMN studies used 250–900mg. At retail, NMN typically costs more per milligram. simplyNAD+ delivers 600mg NR per packet — inside the range used in the trials above — plus three co-factors (quercetin phytosome, trans-resveratrol, PQQ) that are not in a plain NR capsule.

Bottom line

If you want the precursor with the most controlled human trials and the cleanest regulatory footing, that is NR. If you have used NMN and liked it, you are not wrong — but you are paying more for less evidence. Either way, consistency beats molecule: the studies that showed results dosed daily.

The transporter debate

For years the textbook view was that NMN had to lose its phosphate to become NR before entering a cell. In 2019, Grozio et al. (Nature Metabolism) reported that the protein Slc12a8 acts as a dedicated NMN transporter in the mouse small intestine. The finding was immediately contested — Schmidt and Brenner published a critique in the same journal questioning the methodology — and the question is still open. What is not in doubt: NR is taken up by cells directly via nucleoside transporters and converted by the NRK enzymes, a route that has been characterised since Bieganowski and Brenner described the NRK pathway in Cell in 2004. When two molecules end up in the same place, we prefer the one with the better-mapped road.

Stability and handling

Both molecules are hygroscopic and both degrade with heat and moisture. NR is usually stabilised as a salt — nicotinamide riboside chloride or, in simplyNAD+, nicotinamide riboside hydrogen malate — and sealed away from air. This is one reason we chose single-serve liquid packets over a tub: each 10g dose is sealed until you tear it, so the last packet in a box has had the same exposure as the first.

What the trials reported on side effects

In the eight-week Conze et al. (2019) safety study, adults took 100, 300 or 1,000mg of NR per day; adverse events were mild and their frequency was similar to placebo. Dollerup et al. (2018) reported that 2,000mg per day for 12 weeks was well tolerated in overweight men. Unlike niacin (nicotinic acid), NR does not cause the characteristic skin flush. NMN trials at 250–900mg per day (Yoshino 2021; Yi 2023) also reported good tolerability. Neither molecule has a long-term outcome trial yet — the longest human data for either is measured in months.

Can you take both?

There is no established reason to. NR becomes NMN inside the cell, so stacking the two means paying twice for one pathway. If you want to add to an NR product, the more logical additions are compounds that act on different parts of the system — a sirtuin activator, a CD38 inhibitor, or a mitochondrial biogenesis signal — which is the reasoning behind the resveratrol, quercetin phytosome and PQQ in simplyNAD+.

A quick decision guide

• Want the largest number of controlled human trials → NR.
• Want an ingredient with GRAS status and a clean FDA history → NR.
• Already taking NMN and happy with it → there is no urgent reason to switch, but expect to pay more per milligram.
• Whichever you choose → take it daily. Every positive trial dosed every day; none dosed “when you remember”.

Frequently asked

Is NMN banned in the US? Its status as a dietary ingredient has been contested by the FDA since late 2022 and has shifted more than once since; check current FDA guidance before relying on it. NR's status has not been challenged.

Does one absorb faster? Both reach the bloodstream within an hour or two in human pharmacokinetic studies. Speed of absorption is not the deciding factor — daily consistency is.

What dose of NR is in simplyNAD+? 600mg per packet, which sits inside the 250–1,000mg per day range used in the trials above.

Read next: What is NAD+ and why does it decline?

References

Trammell SAJ et al. Nat Commun 2016;7:12948 · Martens CR et al. Nat Commun 2018;9:1286 · Dollerup OL et al. Am J Clin Nutr 2018;108:343–353 · Elhassan YS et al. Cell Rep 2019;28:1717–1728 · Conze D et al. Sci Rep 2019;9:9772 · Yoshino M et al. Science 2021;372:1224–1229 · Yi L et al. GeroScience 2023;45:29–43 · Grozio A et al. Nat Metab 2019;1:47–57 · Schmidt MS, Brenner C. Nat Metab 2019;1:660–661 · Bieganowski P, Brenner C. Cell 2004;117:495–502

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. This article is educational and is not medical advice — talk to your doctor before starting any supplement.