NR vs NMN: what the human evidence shows

Two names turn up on almost every NAD+ supplement label: NR and NMN. The question I am asked most is which one is better. The honest answer has three parts. Human trials so far show that both raise NAD+ in the blood. No trial has shown that either one is better at something you would notice. And in the UK, the two are treated differently by regulators.

This is a plain-English look at what has actually been tested, what has not, and how to read the claims you will see.

What NR and NMN are

Both are NAD+ precursors: smaller molecules that the body can absorb and turn into NAD+, rather than taking NAD+ itself, which does not survive digestion well. NR is nicotinamide riboside. NMN is nicotinamide mononucleotide, which is essentially NR with a phosphate group attached. They are close relatives, which is part of why they behave so similarly in the trials below.

The first direct comparison in humans

Until recently, most of what people quoted came from separate studies of each ingredient, so comparing them meant comparing different trials. A 2026 study in Nature Metabolism changed that. It was a randomised, open-label, placebo-controlled trial in 65 healthy adults, and it compared NR, NMN and plain nicotinamide over 14 days. NR and NMN raised circulating NAD+ concentrations to a similar degree. Nicotinamide did not have the same sustained effect (Christen et al., 2026).

It is worth being clear about its limits. It was open-label, so participants knew what they were taking. It was short, it studied healthy people, and it measured NAD+ in the blood, not how anyone felt or functioned. The authors are from Nestlé Research. The study also proposes that gut bacteria play a part in how NR and NMN raise NAD+, which is a hypothesis the field is still testing.

What the individual NR trials found

A 2018 randomised, placebo-controlled crossover trial in healthy middle-aged and older adults found that six weeks of NR was well tolerated and increased NAD+ metabolism (Martens et al., 2018). A 2019 trial in 12 older men gave 1 g of NR a day for 21 days and found it raised the NAD+ metabolome in skeletal muscle. The same study found no change in the muscle's mitochondrial bioenergetics, which is the measure of how well its energy machinery works (Elhassan et al., 2019). So NR reached the muscle and shifted the chemistry, but that did not show up as a change in that particular measure.

What the individual NMN trials found

Two trials led by a Harvard-affiliated group used a pharmaceutical-grade NMN formulation. In 32 overweight or obese adults aged 55 to 80, 1,000 mg once or twice a day for 14 days produced dose-related increases in blood NAD+ and was well tolerated (Pencina et al., 2023a). In a second trial of 30 overweight or obese adults, 28 days of NMN, at 2,000 mg a day, again raised NAD+ substantially. Changes in muscle strength, fatigability, aerobic capacity and stair-climbing power did not differ significantly from placebo, and insulin sensitivity did not change (Pencina et al., 2023b).

What these trials do not tell us

Every trial above shows that the precursor gets into the body and raises NAD+. None shows that either NR or NMN is better than the other at anything you would feel. Raising a number in the blood is not the same as a change in how someone's body works, and the trials that looked at strength and fitness did not find a difference from placebo.

There is also a dose gap. Several of these trials used 1,000 mg or more a day. The UK authorisation for NR chloride, covered below, is capped well below that. Results at trial doses should not be assumed to carry over to a supplement sold at the legal dose.

How UK rules treat them

Nicotinamide riboside chloride is an authorised novel food in Great Britain, approved for use in food supplements. The authorisation sets a maximum of 300 mg a day for adults, and 230 mg a day for pregnant and breastfeeding women, and requires the ingredient to be named "nicotinamide riboside chloride" on the label (Food Standards Agency, 2025).

For NMN, the Food Standards Agency register lists an application that is still at the risk-assessment stage. At the time of writing, on 23 October 2026, I could not find an authorisation (Food Standards Agency, 2026). That is not the same as a ban, and I am not a lawyer, so I will not offer a legal view on products already on sale. It does mean there is no UK authorisation to point to, and it is a fair question to ask any seller.

Where TREMODI fits

I should be upfront: TREMODI contains NR, so I have a stake in this question. I chose NR partly because of the human data above and partly because it is authorised for food supplements in Great Britain. TREMODI contains nicotinamide riboside chloride, and the formula page sets out the amount and the other eight ingredients. It is a food supplement, not sold as a treatment or cure for anything.

How to compare products

Whatever you are buying, three questions are worth asking. Which form is it, and is that form authorised in the UK? What amount is in a daily serving, and how does it compare with the authorised maximum? And what human evidence exists for that form? If a label or an advert cannot answer those, that tells you something.

References

Christen, S. et al. (2026) 'The differential impact of three different NAD+ boosters on circulatory NAD and microbial metabolism in humans', Nature Metabolism, 8(1), pp. 62–73. https://doi.org/10.1038/s42255-025-01421-8

Elhassan, Y.S. et al. (2019) 'Nicotinamide riboside augments the aged human skeletal muscle NAD+ metabolome and induces transcriptomic and anti-inflammatory signatures', Cell Reports, 28(7), pp. 1717–1728.e6. https://doi.org/10.1016/j.celrep.2019.07.043

Food Standards Agency (2025) Authorised regulated food and feed products for Great Britain: nicotinamide riboside chloride (NOVEL-96). Available at: https://data.food.gov.uk/regulated-products/novel_authorisations/novel-96 (Accessed: 23 October 2026).

Food Standards Agency (2026) Register of regulated product applications: β-nicotinamide mononucleotide (RP-2116). Available at: https://data.food.gov.uk/regulated-product-applications/id/application/RP-2116.html (Accessed: 23 October 2026).

Martens, C.R. et al. (2018) 'Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD+ in healthy middle-aged and older adults', Nature Communications, 9, article 1286. https://doi.org/10.1038/s41467-018-03421-7

Pencina, K.M. et al. (2023a) 'MIB-626, an oral formulation of a microcrystalline unique polymorph of β-nicotinamide mononucleotide, increases circulating nicotinamide adenine dinucleotide and its metabolome in middle-aged and older adults', The Journals of Gerontology: Series A, 78(1), pp. 90–96. https://doi.org/10.1093/gerona/glac049

Pencina, K.M. et al. (2023b) 'Nicotinamide adenine dinucleotide augmentation in overweight or obese middle-aged and older adults: a physiologic study', The Journal of Clinical Endocrinology and Metabolism, 108(8), pp. 1968–1980. https://doi.org/10.1210/clinem/dgad027