Longevity supplements
NMN and NAD+ Supplements: What the 2026 Trial Actually Showed
Reviewed by a qualified clinician · analysed at UKAS-accredited UK labs (ISO 15189)
Last reviewed July 20268 min read
Every Helvy guide is written by our health editors, then checked by a qualified clinician before it goes live and re-checked as the science moves. We name clinical roles, not individuals, until each reviewer has agreed to be credited publicly. This is wellness guidance to help you understand your own data, not a diagnosis.
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A January 2026 trial in 65 adults showed NMN and NR raise NAD+ in the blood over 14 days. Plain nicotinamide did not. But the study measured a chemical, not your health. No trial has yet shown that a higher NAD+ level makes you feel or age better. There is also no routine UK test for it.
Check what you can actually measure →As of July 2026. The NAD+ conversation got louder this year for two reasons. In January, Nature Metabolism published the first proper human head-to-head of the three main NAD+ boosters (Christen et al., January 2026). Then in May, NPR ran a piece on the clinics selling NAD+ drips, in which one ageing researcher said the cart “may be well ahead of the horse”.
Both things are true at once. The science moved forward this year. The marketing is still a long way in front of it. This guide covers what the new trial proved, the much bigger thing it did not test, and the cheaper question worth answering before you commit to a habit that runs to £70 a month.
1. Why is NAD+ suddenly everywhere?
NAD+ is a molecule your cells use to turn food into energy. It is involved in hundreds of reactions, including DNA repair. Levels appear to fall as we get older. That single fact is the foundation the entire longevity category is built on.
The pitch follows naturally. Top the molecule back up and you slow the clock. It is a tidy story, and in mice it has produced striking results. One researcher quoted by NPR put the gap plainly: in rodents, NAD+ looks miraculous. In humans, that has not been shown.
You cannot usefully swallow NAD+ itself, because it is poorly absorbed. So supplements sell precursors instead. The three that matter are nicotinamide mononucleotide (NMN), nicotinamide riboside (NR) and plain nicotinamide (a form of vitamin B3). All three are vitamin B3 derivatives.
2. What did the 2026 trial actually find?
Until this year, nobody had compared the three head to head in people. The January 2026 study did exactly that. It was a randomised, open-label, placebo-controlled trial in 65 healthy adults, who took one of the three precursors or a placebo once daily for 14 days.
Two findings stand out. First, NMN and NR both raised whole-blood NAD+ over the fortnight, by a similar amount. Plain nicotinamide did not. That is a genuine answer to a question the supplement industry had been arguing about for a decade.
Second, and more surprising, the route runs through your gut. The authors found the effect depends on gut bacteria converting the supplement into nicotinic acid, which your tissues then use to build NAD+. Your microbiome is part of the machinery. That implies the response could vary quite a lot from person to person.
3. What the trial never measured
This is the part that gets lost. The study measured NAD+ and related chemicals in blood. It did not measure whether anyone had more energy, slept better, aged more slowly or improved a single marker of health.
That distinction matters more than it sounds. Raising a number in the blood is a surrogate endpoint. It is a stand-in for the thing you actually care about. Medicine is full of surrogates that moved beautifully while the outcome underneath refused to budge.
So the honest summary is narrow but real. We now know NMN and NR reliably raise NAD+ in healthy adults, and roughly how. We still do not know whether doing so does anything for you. The human trials testing that are small, mixed, and mostly in specific patient groups rather than healthy people hoping to age well.
4. NMN, NR or plain vitamin B3?
On the evidence available, three practical points follow.
- NMN and NR performed the same. Paying a premium for one over the other is not supported by this trial.
- Cheap nicotinamide is not a substitute. It did not produce the sustained rise the other two did.
- Dose claims are unanchored. No trial has established the dose that delivers a health benefit, because no trial has established the benefit.
It is also worth remembering what these compounds are. They are derivatives of a vitamin most of us already get enough of. The NHS is direct about the parent nutrient.
“You should be able to get all the niacin you need from your daily diet.”
— NHS, B vitamins and folic acid
The NHS also notes that high doses of nicotinic acid supplements can cause skin flushing. Safety in the published NAD+ trials has looked reassuring so far. But these are short studies, and nobody has run a multi-year one. If you take medication or have a liver condition, speak to a qualified clinician first.
5. Can you test your NAD+ level in the UK?
Not in any meaningful way, and we would rather say so than sell you something. NAD+ is unstable in a blood sample and is measured with specialist research methods. It is not a routine UK laboratory test, and Helvy does not offer it.
There is a deeper problem too. Even a perfect NAD+ reading would not tell you much, because no agreed healthy range exists and no outcome has been tied to a given level. You would have a number without a meaning.
Which leaves an awkward position for anyone spending real money here. You are buying a supplement whose effect you cannot measure, for a benefit not yet demonstrated. That is a reasonable bet to make knowingly. It is a poor one to make by accident.
6. The markers worth measuring instead
Here is the useful move. Several markers do track how your body is ageing, they are measurable today, and each one has decades of outcome data behind it. If longevity is the goal, this is where the evidence actually sits.
- ApoB. A count of the cholesterol-carrying particles that drive artery furring. It is a sharper read than standard cholesterol testing. See our ApoB guide.
- Lp(a). An inherited risk marker you only need to check once. Most GPs never run it. Our Lp(a) guide explains why it matters.
- hs-CRP. A sensitive marker of the low-grade inflammation linked to ageing. The CRP guide covers how to read it.
- Your full lipid picture. LDL, HDL, triglycerides and non-HDL cholesterol, read together rather than one at a time.
Helvy's Advanced Heart Health panel (£159) covers ApoB, Lp(a) and hs-CRP alongside the full cholesterol picture. It is a home finger-prick test processed by UKAS-accredited UK laboratories, with results in around 5 working days. Our heart health hub and longevity blood tests guide go deeper on how these markers fit together.
None of this is an argument against trying NMN. It is an argument for knowing your starting point first. If your ApoB is high or your hs-CRP is raised, that is a lever with real evidence behind it, and it is one you can actually watch move.
READY TO TEST?
Measure the things that have outcome data behind them
Helvy's Advanced Heart Health panel reports ApoB, Lp(a), hs-CRP and your full cholesterol picture with clear, plain-English context. One home finger-prick test, results in around 5 working days from UKAS-accredited UK laboratories.
Frequently asked questions
Do NMN supplements actually work?
They work at raising NAD+ in the blood. A January 2026 trial in 65 healthy adults showed NMN and NR both did this over 14 days, while plain nicotinamide did not. What no study has yet shown is that a higher NAD+ level improves energy, health or ageing in healthy people. That gap is the whole debate.
Is NMN or NR better?
On the only human head-to-head we have, neither. The 2026 trial found NMN and NR raised NAD+ by a comparable amount over 14 days. So paying a premium for one over the other is not supported by the current evidence. Plain nicotinamide behaved differently and did not produce the same sustained rise.
Can you test your NAD+ levels in the UK?
Not routinely. NAD+ is unstable in a blood sample and is measured using specialist research methods rather than standard UK laboratory tests. There is also no agreed healthy range, so even a result would be hard to interpret. Helvy does not offer an NAD+ test.
Are NAD+ supplements safe?
Published trials so far have reported reassuring safety, but they are short and the longest run only weeks to months. The NHS notes that high doses of nicotinic acid supplements can cause skin flushing. If you take medication, have a liver condition or are pregnant, speak to a qualified clinician before starting.
What should I test before buying longevity supplements?
Start with markers that have real outcome data and can be tracked over time. ApoB and Lp(a) reflect cardiovascular risk, hs-CRP reflects low-grade inflammation, and your full lipid picture puts both in context. These tell you where your actual risk sits, which a supplement label cannot.
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