NMN works in mice. What happened when 80 people took it?
NMN is one of the most talked about supplements in longevity circles. Most of the excitement comes from mice. So what happens when people take it? One trial with 80 adults gives a first look, and it is worth reading closely before you believe the headlines.
Short answer
- In mice, NMN raised NAD levels and slowed some signs of aging.
- In a 60 day human trial, blood NAD went up and people walked a bit further in a six minute walking test.
- Insulin resistance did not change. The trial was short, small and partly run by NMN makers. There is no long term data in humans.
What NMN is
NMN stands for nicotinamide mononucleotide. Your body uses it to make NAD, a molecule that cells need to turn food into energy and to repair themselves. NAD levels tend to drop with age. The idea behind NMN is simple: give the body more of the building block, and NAD might go back up.
What the mouse research showed
The best known mouse study came out in 2016 (Mills et al., Cell Metabolism). Mice got NMN in their drinking water for a year. Compared with mice that did not get it, they gained less weight with age, used energy better and kept some body functions in better shape.
That sounds promising. But mice are not people. They live about two years, they eat a fixed diet in a lab, and many results from mice never show up in human trials. So the real question is what happens in people.
The human trial
In 2022 a group of researchers published a trial in the journal GeroScience (Yi et al., 2023). This is how it was set up:
- Who: 80 healthy middle aged adults.
- How long: 60 days.
- What: each person took 300 mg, 600 mg or 900 mg of NMN a day, or a placebo.
- Design: randomised and double blind, so neither the people nor the researchers knew who got what.
All 80 people finished the trial.
What it found
Blood NAD went up. In all three NMN groups, NAD in the blood rose clearly compared with placebo. The 600 mg and 900 mg groups had the highest levels. This was the main thing the trial set out to measure.
People walked a little further. In a six minute walking test, the NMN groups improved more than the placebo group.
Insulin resistance did not change. The researchers measured HOMA IR, a common marker for how well the body handles blood sugar. There was no real difference between NMN and placebo.
The researchers also reported no safety problems during the 60 days. They tracked a few other measures, such as a self rated health survey and a "biological age" score from a blood test calculator. Those leaned in favour of NMN too, but they are softer measures and easy to overread.
The catch
This trial is a useful first step. It is not proof that NMN slows aging in people. Four things to keep in mind:
- It was short. Sixty days says nothing about what happens over years.
- It was small. About 20 people per group. Small trials can find effects that later shrink or vanish.
- Some authors worked for NMN makers. The conflict of interest statement lists employees of NMN suppliers among the authors. That does not make the data wrong, but it is a reason to wait for independent trials.
- No lifespan data in humans. Higher NAD in the blood is a lab number. Whether it means a longer or healthier life is still unknown.
How to read studies like this
This study is a good example of a pattern you will see often in supplement news. A strong mouse result, then a small human trial that confirms a lab marker, then headlines that skip the gap between the two.
A few questions help when you read the next one:
- Was it done in animals or in people?
- How many people, and for how long?
- Did it measure a lab value, or something you would notice in daily life?
- Who paid for it, and who wrote it?
An example
Sam sees a post saying NMN "reverses aging". Sam looks up the study behind it and finds this trial. Sixty days, 80 people, NAD up, walking a bit better, blood sugar marker unchanged, partly run by suppliers. That is a lot less than the post promised. Sam decides to keep an eye on new research and to ask a doctor before trying any supplement.
Try it yourself
Next time you read about a supplement, check who was studied and for how long. Want to keep track of what you eat with your own AI? Try it free for 7 days.
This post is general information, not medical or dietary advice. Talk to your doctor before you take any supplement.
Sources
- Yi L., Maier A. B., Tao R., Lin Z., Vaidya A., Pendse S., Thasma S., Andhalkar N., Avhad G., Kumbhar V. (2023), "The efficacy and safety of β-nicotinamide mononucleotide (NMN) supplementation in healthy middle-aged adults: a randomized, multicenter, double-blind, placebo-controlled, parallel-group, dose-dependent clinical trial", GeroScience 45(1): 29 to 43. doi.org · PubMed
- Mills K. F., Yoshida S., Stein L. R. et al. (2016), "Long-Term Administration of Nicotinamide Mononucleotide Mitigates Age-Associated Physiological Decline in Mice", Cell Metabolism 24(6). doi.org
Video transcript
NMN works in mice. So what happened when eighty humans took it? In a sixty-day trial, healthy middle-aged adults took three hundred, six hundred or nine hundred milligrams a day, or a placebo. Blood NAD rose in all the NMN groups, and people walked further in a six-minute walking test than on placebo. Insulin resistance didn't change. The catch: it was short, small, and the authors worked for NMN suppliers. [Note: to be precise, 3 of the 10 authors did.] There's no long-term or lifespan data in humans. PastePlate-AI: your own AI, a fixed memory, day, week and month reports.
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This blog does not give medical advice. Health disclaimer.