Short answer: NMN and NR both raise blood NAD+, and the best head-to-head trial so far found no meaningful difference between them. A 2026 study in 65 adults found 1,000mg a day of either roughly doubled circulating NAD+ in 14 days. Neither has been shown to slow ageing in humans. Choose on price, testing and dose, not on claims that one is superior.

What Are NMN and NR?

NMN and NR are both precursors of NAD+, a coenzyme your cells use for energy metabolism and DNA repair. NAD+ levels fall with age, which is why both are sold as longevity supplements. Structurally they’re almost identical. NMN carries a phosphate group and NR doesn’t.

The theory goes that NMN must be better because it’s one step closer to NAD+. In practice the body doesn’t seem to work that way. NMN is thought to be converted to NR before it enters many cells, and the 2026 trial found that gut bacteria convert both compounds substantially before they’re absorbed.

NMN vs NR: Which Raises NAD+ More?

They’re roughly equal. The largest direct comparison is a randomised, placebo-controlled study published in Nature Metabolism in January 2026. It found that 14 days of NR or NMN raised circulating NAD+ by similar amounts in 65 healthy adults, while nicotinamide did not.

A much smaller crossover study reported a larger NAD+ rise with NR, but it had very few participants and results varied widely between them. Until a larger trial says otherwise, call it a tie.

Does Higher NAD+ Actually Do Anything?

This is the real question, and so far the answer is disappointing. A 2025 systematic review and meta-analysis of randomised trials in adults over 60 concluded that current evidence doesn’t support NMN or NR for preserving muscle mass or function. A 2025 meta-analysis of NMN trials looked at glucose and lipid markers and found the evidence for metabolic benefit unconvincing. Smaller trials report scattered positive signals, such as insulin sensitivity in one group of prediabetic women, but none add up to a proven anti-ageing effect.

Safety: NMN vs NR

Both were well tolerated in trials lasting up to several months. Reported side effects were mild: occasional nausea, flushing or digestive upset. Long-term data is thin for both. Very high doses of nicotinamide-related compounds may affect methylation and homocysteine, so more is not better.

Price: Which Is Better Value?

Because NAD+ results are similar, cost per day matters most. On 14 November 2026, Aeternum’s NMN 500mg capsules cost £23 for 60 capsules (UK display price). That’s about £0.38 a day at 500mg or £0.77 at the 1,000mg trial dose. Patented NR products generally cost more per milligram, though NR has more years of published safety data.

Which Should You Choose?

• Choose NMN if cost per milligram matters most and you’re happy with a supplement backed by blood-marker data only.
• Choose NR if you prefer the ingredient with the longer published human safety record.
• Choose neither if you want a proven anti-ageing effect. That evidence doesn’t exist yet. Start with exercise, sleep and diet.
• Don’t take both. There’s no evidence the combination adds anything.

How NMN and NR Are Absorbed

On paper, NMN looks like the shortcut: it’s one enzymatic step from NAD+, while NR needs two. In practice the route through the body is messier. NMN carries a phosphate group, which makes it harder to move into many cells. A good share is thought to be converted to NR outside the cell first, then rebuilt into NMN and NAD+ inside.

The 2026 Nature Metabolism trial added another twist. When researchers fermented NR and NMN with human gut bacteria, both were converted to nicotinic acid (another form of vitamin B3), and both boosted microbial growth. So part of what you swallow is processed by your gut bacteria before your own cells see it. That helps explain why the two end up raising blood NAD+ by similar amounts despite their different chemistry.

Dosing Compared

A sensible approach is to start at 250–500mg a day and only go up to 1,000mg if you have a reason to, such as matching a trial dose. Taking it in the morning is a common habit, but no trial has shown that timing matters.

What the Older NR Trials Found

NR has the longer human track record. In a 2018 randomised crossover trial in healthy middle-aged and older adults, 1,000mg of NR a day for six weeks was well tolerated and raised NAD+ in blood cells. Blood pressure and arterial stiffness showed hints of improvement, but these weren’t the trial’s main endpoints and need confirming. A 2023 review of 25 published human NR studies reached a cautious overall verdict: NR consistently raises NAD+, but the clinical benefits are still unproven.

NMN’s trials are newer and mostly smaller. A 2024 trial in 60 older adults found blood NAD+ rose on 250mg a day, but the main physical test didn’t beat placebo. In other words, the two supplements are at a similar stage: the blood marker moves reliably, and the health benefits are still being looked for.

Should You Test Your NAD+ Levels?

Home finger-prick NAD+ tests are widely sold. They can show whether a supplement is raising your blood NAD+, which is the one thing both precursors reliably do. They can’t tell you whether that rise is doing you any good, and there’s no agreed ‘healthy’ NAD+ range. If you’re curious, one test before and one after 4–6 weeks will tell you whether your chosen supplement is being absorbed. Beyond that, the extra tests add little.

Who Should Choose Which?

NMN vs NR FAQ