If you've been researching NAD+ supplements, you've probably seen two acronyms come up over and over: NMN and NR. Both are sold as ways to raise NAD+ levels in your body. Both have published human research behind them. Both have ardent supporters and outspoken critics.
This guide explains what each one actually is, what the human evidence shows for each, and how to decide which is right for you. We'll be upfront — Ivvion makes NMN, not NR. We'll explain why we made that choice. You can take it or leave it.
A 60-second primer on NAD+
To understand the difference between NMN and NR, you need to understand what they're both trying to do.
NAD+ (nicotinamide adenine dinucleotide) is a coenzyme found in every cell of your body. It powers cellular energy production and activates the enzymes responsible for DNA repair and cellular maintenance. The amount of NAD+ in your tissues declines steadily from young adulthood onward; by age 50 it's roughly half of what it was at 25.
You can't take NAD+ directly — the molecule is too large to absorb through the gut intact. So supplement researchers have focused on precursors: molecules your body can convert into NAD+.
The two leading precursors on the market are NMN and NR. Both work. The differences are technical, and worth understanding before you spend money on either.
What is NR?
NR stands for nicotinamide riboside. It's a form of vitamin B3 that the body converts into NAD+ through a multi-step pathway: NR → NMN → NAD+.
NR was the first NAD+ precursor to reach the consumer supplement market in a serious way, starting around 2013 when ChromaDex licensed it under the brand name Niagen. Most premium NR supplements use Niagen as their raw material.
The case for NR rests on three things. First, NR has been on the market longer than NMN, which means more cumulative human safety data. Second, NR is smaller than NMN, which some researchers have argued makes it easier to absorb. Third, NR has been through multiple peer-reviewed human trials demonstrating that it raises NAD+ in blood.
The case against NR rests on one thing. NR has to be converted into NMN before it becomes NAD+. So if your body's conversion machinery for that step is slow or impaired (which it can be in older adults), you may be getting less of the active molecule than you think.
What is NMN?
NMN stands for nicotinamide mononucleotide. It's one biochemical step closer to NAD+ in the conversion pathway: NMN → NAD+ directly.
NMN reached the consumer market later than NR, gaining real traction around 2018–2020. The most well-studied branded form of NMN is Uthever®, manufactured under pharmaceutical-grade conditions and used in most of the human clinical trials referenced below.
The case for NMN rests on three things. First, it's the direct precursor to NAD+, skipping a conversion step. Second, the most recent and physiologically meaningful human trials (improvements in insulin sensitivity, walking speed, aerobic capacity) have been on NMN, not NR. Third, the absorption story has been resolved by newer delivery technology — sublingual and liposomal NMN formulations get the molecule into the bloodstream effectively.
The case against NMN was historically that the molecule is larger than NR and might be harder to absorb. The evidence for this has weakened as better-designed absorption studies have been published, but it's still an honest critique.
What the human studies actually show
Here's the part that most of the internet skips. Let's look at the strongest human trials for each precursor.
NR — the major human trials
Martens et al, 2018, published in Nature Communications. University of Colorado Boulder. 24 healthy adults aged 55–79 given 500 mg of NR twice daily (1,000 mg/day) for 6 weeks. NR group showed increased NAD+ in blood and reduced systolic blood pressure. Small trial, modest effects.
Conze et al, 2019, published in Scientific Reports. A double-blind trial of 140 healthy overweight adults given 100, 300, or 1,000 mg of NR for 8 weeks. NR raised NAD+ levels dose-dependently. No clinically meaningful changes in metabolic markers.
Remie et al, 2020, published in the American Journal of Clinical Nutrition. Maastricht University. 13 overweight insulin-resistant men given 1,000 mg of NR for 6 weeks. NR raised NAD+ but did not improve insulin sensitivity or other metabolic markers (a negative result worth noting).
The pattern across NR trials: NAD+ goes up in blood, downstream physical or metabolic outcomes are inconsistent.
NMN — the major human trials
Yoshino et al, 2021, published in Science. Washington University in St Louis. 25 postmenopausal prediabetic women given 250 mg of NMN per day for 10 weeks. Roughly 25% improvement in muscle insulin sensitivity versus placebo. This is one of the few NAD+ precursor trials with a clear, clinically meaningful downstream outcome.
Igarashi et al, 2022, published in npj Aging. Keio University, Japan. 108 healthy older adults (mean age 65) given 250 mg of NMN daily for 12 weeks. Improvements in walking speed and grip strength.
Liao et al, 2023, published in the Journal of the International Society of Sports Nutrition. Recreational runners given 300 mg of NMN daily for 6 weeks. Improvements in aerobic capacity (ventilatory threshold).
The pattern across NMN trials: smaller doses (250–300 mg) produced measurable physical outcomes — insulin sensitivity, strength, aerobic capacity. The downstream effects look stronger than what's been seen in NR trials at higher doses.
Honest caveats
We need to flag what these comparisons don't show.
These are still small trials. None of them is a 10,000-person mega-study. The effect sizes are modest. The long-term effects of multi-year supplementation with either precursor are still being studied. And direct head-to-head trials of NMN vs NR in the same study are vanishingly rare — most of what we have is indirect comparison across separately-designed studies, which is always weaker evidence.
Also, NR has had more time on the market. There's more cumulative safety data. Both are well-tolerated in the doses studied, but NR has been taken by more people for longer.
How to choose between NMN and NR
Here's a practical framework.
Pick NR if: you want the option with the longest cumulative human safety record. You've taken NR before and felt good results. You prefer a single-step branded ingredient (Niagen) where the supply chain is consistent.
Pick NMN if: you want the precursor with the strongest recent human-trial evidence on downstream physical outcomes. You're willing to take a slightly newer category in exchange for that. You can afford to choose a premium liposomal delivery system if absorption is a concern.
Pick both? Some longevity protocols stack NMN and NR together. There's no strong evidence this is meaningfully better than either alone, and it's expensive. We don't recommend it for most people.
Pick neither (yet) if: you're under 35 and healthy. The NAD+ decline is gentler in the first half of adulthood; the case for supplementing is weaker. Food (broccoli, edamame, milk, brewer's yeast contain trace amounts), sleep, exercise, and not being chronically over-stressed do more for your NAD+ than any pill.
Why Ivvion makes NMN and not NR
We considered both when we were designing the Ivvion longevity range. We chose NMN for three reasons.
First, the recent human evidence on NMN is the strongest in the category — the Washington University insulin sensitivity result and the Keio walking speed/grip strength result are the kind of physiologically meaningful outcomes that justify a supplement existing.
Second, the delivery technology problem (NMN being a larger molecule than NR) has been largely solved by liposomal formulations. Our Elite formula uses LipoAvail™ to encapsulate the NMN molecule in a lipid shell that protects it through the digestive tract.
Third, the Uthever® supply chain — the branded form of NMN used in most of the published studies — is well-established and pharmaceutical-grade. We can verify what's in our bottles.
None of this means NR is a bad choice. It's a credible choice. We just thought the NMN story was stronger as the foundation of a longevity range.
Frequently asked questions
Can I switch from NR to NMN, or vice versa? Yes. Both raise NAD+ via the same downstream pathway. There's no withdrawal effect, no need to taper. If you've been taking one and want to try the other, just switch.
Should I take NMN and NR together? There's no evidence this is meaningfully better than either alone. It's expensive and probably unnecessary.
Is NMN better absorbed sublingually or as a capsule? Sublingual NMN bypasses some digestive degradation, which is theoretically better, but the trade-off is taste and inconvenience. Liposomal capsules (like our Elite formula) achieve similar absorption gains without the taste problem.
Which is cheaper per gram? Generic NR (non-Niagen) tends to be slightly cheaper than generic NMN per gram. Branded versions (Niagen NR, Uthever® NMN) are roughly comparable.
Has anyone done a direct NMN vs NR head-to-head trial? A few small studies have attempted direct comparisons, but the field is still waiting for a well-powered head-to-head trial. The current evidence is mostly indirect.
Is NMN or NR legal in the UK? Both are legal in the UK as food supplements. Neither has an authorised health claim on the GB NHC Register, so no brand can market either as treating, preventing, or curing disease.
What to do next
If you've read this far, you're in the small minority of people who actually research their supplements rather than buying based on Instagram ads. That's a good instinct.
If you've decided NMN is for you, we make two:
Ivvion NMN Essential — clinical-trial-dose NMN using Uthever® raw material. Best starting point if you've never taken NMN before.
Ivvion NMN Elite — higher-strength NMN with LipoAvail™ liposomal delivery. Best if you've taken NMN before or you want maximum absorption.
Both backed by a 30-day money-back guarantee. £10 off your first bottle with code WELCOME10.
If you've decided NR is for you, look at brands that use Niagen as the raw material rather than unbranded NR — you'll get a verifiable supply chain.