NMN vs NAD+: what's the difference?

NMN (nicotinamide mononucleotide) is a precursor: a smaller molecule that cells turn into NAD+ in a single enzymatic step. NAD+ (nicotinamide adenine dinucleotide) is the coenzyme itself, the form cells use, so the difference between NMN and NAD+ is one reaction, and the practical differences (how each is taken, how much of it survives the journey, what has been tested in people, and whether it is authorised for sale in the UK) all follow from that.

We sell NAD+ as an injectable kit, so we are not a neutral party here. Each research claim below links to the paper or regulator page it comes from.

Is NMN the same as NAD+?

No, though NMN is part of NAD+. An enzyme that cuts NAD+ at one particular bond leaves NMN and AMP (Nikiforov et al., 2011), and inside the cell a family of enzymes called NMNATs builds NAD+ from NMN (Covarrubias et al., 2021). NAD+ is the working molecule. It is a coenzyme for the redox reactions at the centre of energy metabolism, and enzymes such as sirtuins and PARPs use it up as they work (Covarrubias et al., 2021). Our science page sets out what NAD+ does inside a cell in more detail.

NR (nicotinamide riboside) is the other precursor you will see on supplement labels. It sits one step further back: cells convert NR into NMN using enzymes called NR kinases, and then NMN into NAD+ (Covarrubias et al., 2021). The same review describes a gradual fall in NAD+ in tissues and cells with age, in rodents and in humans, and that fall is the usual reason given for taking any of the three.

If you have seen NAD+ listed next to peptides, our guide on whether NAD+ is a peptide covers what it is chemically.

How cells turn NMN into NAD+

Cells have three routes to NAD+: from the amino acid tryptophan, from nicotinic acid, and by recycling what they have already used. The recycling route, called the salvage pathway, supplies most of it (Covarrubias et al., 2021).

Every enzyme that consumes NAD+ leaves nicotinamide behind. An enzyme called NAMPT turns that nicotinamide into NMN, and the NMNATs turn NMN back into NAD+. NAMPT is the rate-limiting enzyme of the pathway, the slowest link in the chain (Covarrubias et al., 2021). NMN enters after that bottleneck. A 2021 trial paper describes NMN availability as a rate-limiting factor in how mammals make NAD+ (Yoshino et al., 2021), and that is the usual argument for taking it.

How NMN gets into a cell is still argued over. In cultured human cells, NMN outside the cell was converted to NR, taken in as NR, and rebuilt into NMN inside (Nikiforov et al., 2011). A transporter specific to NMN, called Slc12a8, has since been found in the small intestine, and the 2021 review that describes it says more work is needed to show how much it matters (Covarrubias et al., 2021). So the single step from NMN to NAD+ happens inside the cell, and getting NMN there may involve a detour through NR.

Does swallowed NAD+ survive digestion better than NMN?

NAD+ is a large, highly polar molecule. A 2021 review of NAD+ pharmacology reports that several studies found NAD+ taken by mouth did not effectively raise NAD+ in blood or tissue. It gives two reasons: breakdown in the gut lowers how much is absorbed, and the molecule's polarity stops it passing through cell membranes on its own (She et al., 2021). The same review notes that the idea that cells cannot take up NAD+ whole may yet be challenged, because an NAD+ transporter has been identified.

Precursors lose part of their dose as well. In mice given labelled NR or NMN by mouth, most of it was converted to nicotinamide in the liver before reaching other tissues, while the same molecules given into a vein reached several tissues intact (Liu et al., 2018). A 2025 mouse study found that only a small portion of swallowed NMN and NR was absorbed directly from the small intestine; gut bacteria converted most of it first (Yaku et al., 2025).

In people, oral NMN and NR do raise the NAD+ measured in blood, as the trials further down show. Blood is the easy thing to sample, though. One NMN trial that also took muscle biopsies found NAD+ in blood cells went up while NAD+ in muscle did not change (Yoshino et al., 2021).

How injected NAD+ compares with oral NMN

An injection avoids the gut and the liver's first pass, which is where the mouse studies above lose most of a swallowed dose. That is why we sell NAD+ as an injectable kit rather than a capsule: a pre-mixed 1000mg vial, a reusable metal auto-injector, and single-use needles and wipes, sold as a food supplement. How our at-home NAD+ injection kit works covers the practical side.

What happens after the injection is less well mapped. NAD+ does not cross cell membranes freely (Covarrubias et al., 2021), and in cultured human cells, NAD+ outside the cell was broken down to NR before the cells used it (Nikiforov et al., 2011). In the 2025 mouse study, NMN and NR given into a vein were quickly broken down to nicotinamide too (Yaku et al., 2025). Changing the route changes where a dose is broken down, and possibly how much is lost on the way.

Human data on injected NAD+ is thin. The study usually cited is a 2019 pilot of an intravenous drip, in which eight men received 750mg of NAD+ over six hours and three more were given saline. For the first two hours, NAD+ in the plasma of the men given NAD+ did not rise at all, which the authors read as rapid uptake into tissue or breakdown. No adverse events were observed during the infusions (Grant et al., 2019). We have not found a published human study of NAD+ given by injection rather than by drip, or one that compares injected NAD+ with oral NMN.

What has been tested in people

For NMN, a 2026 review found 15 randomised trials that met its criteria, using 250mg to 2,000mg a day for between two and 24 weeks. Pooled, they showed no significant effect on body weight, fasting glucose, HbA1c, blood lipids or systolic blood pressure, and a slight fall in diastolic blood pressure that the authors describe as a preliminary signal (Yang et al., 2026).

Two of those trials show the range. In the first, 25 postmenopausal women with prediabetes who were overweight or obese took 250mg of NMN or a placebo daily for ten weeks. NAD+ in the blood cells of the NMN group rose, and the trial's main measure, how their muscle responded to insulin, rose in the NMN group and not in the placebo group (Yoshino et al., 2021). In the second, 80 middle-aged adults took 300mg, 600mg or 900mg of NMN or a placebo for 60 days; blood NAD+ rose in every NMN group and was highest at 600mg and 900mg. The companies that made the NMN co-sponsored it (Yi et al., 2023).

NR has been studied in people since 2016, when the first clinical trial of it ran (Damgaard and Treebak, 2023). In a six-week crossover trial, 30 healthy adults aged 55 to 79 were randomised to 1,000mg of NR a day or a placebo, and NR lifted NAD+ in their blood cells by about 60% compared with placebo (Martens et al., 2018). A 2023 review of the 25 published papers on NR in humans concluded that it had shown few clinically relevant effects, and that the literature tends to overstate how important and reliable its findings are (Damgaard and Treebak, 2023).

Counting studies alone, oral NR has the most human research behind it, then NMN, while injected NAD+ has the single IV pilot described above. People who have tried NMN and moved on give their own reasons, which our guide on why people stop taking NMN goes through.

NR vs NMN in a head-to-head study

In 2026 a team in Bergen, Norway, gave six healthy volunteers 600mg of NR twice a day for eight days and, in a separate period, 600mg of NMN on the same schedule, in random order. Blood NAD+ followed the same time course with both, which the authors take as a sign of a shared pathway, but NR produced the larger rise (Berven et al., 2026). Blood NAD+ took about two weeks to level off, and how far it rose differed a great deal between people. The authors say trials with matched doses and controlled meal timing are needed before either can be called better absorbed.

NAD+ vs NMN (and NR) side by side

Is NMN authorised in the UK?

As of September 2026, no. In Great Britain a novel food is one that was not eaten to a significant degree in the UK or the EU before 15 May 1997, and novel foods need to be authorised before they can be sold (Food Standards Agency guidance).

The FSA's register of authorised novel foods has no entry for NMN. A search of it for "nicotinamide" returns two substances, nicotinamide riboside chloride and 1-methylnicotinamide chloride (FSA register). The FSA's separate register of applications lists one for β-nicotinamide mononucleotide as a novel food ingredient, from the applicant Effepharm (Shanghai) Ltd., with its status given as in progress at the risk assessment stage and no date for a decision (FSA application RP-2116).

NR is in a different position. Nicotinamide riboside chloride has been authorised for use in food supplements in Great Britain since 2020, at up to 300mg a day for adults and 230mg a day for pregnant and breastfeeding women (FSA authorisation NOVEL-96).

Should you take NMN or NAD+?

It depends on the person, and a doctor or pharmacist who knows your history is better placed to help you choose than a company that sells one of the options.

NMN and NR are swallowed; our NAD+ is an injection you give yourself at home with an auto-injector. If you do not want to use a needle, that decides it.

The oral precursors have far more human trials behind them than injected NAD+ does, although reviews of the trials for both have found few clear clinical effects so far. In the UK, NR is an authorised novel food and NMN, as of September 2026, is not.

People respond differently. In the head-to-head study, the rise in blood NAD+ varied widely from one volunteer to the next (Berven et al., 2026), so someone else's experience with either is a weak guide to yours. Speak to a doctor first if you are pregnant, breastfeeding, taking prescribed medication or under medical supervision. Our kit is not for anyone under 18.