Healthspan guide
NAD+, NMN, and the research that made this interesting
Your cells use a molecule called NAD+ to make energy and to repair damaged DNA. NMN is the raw material they build it from.*
NAD+'s role there is settled biochemistry rather than marketing, and it's why a serious research field grew up around this molecule. What follows is what that research has found, who is doing it, and where it has reached so far.
Every study named here has an author and a date so you can read it yourself.
- NAD+ does two jobs your cells can't run without. It carries the electrons that turn food into energy, and it's the raw material the PARP enzymes consume while they repair damaged DNA.*
- NMN sits one enzyme step away from it. That's why almost every product in this category sells a precursor rather than NAD+ itself.
- Blood NAD+ rises on oral NMN, and that's now been shown against a placebo. Yi and colleagues took 80 adults out to 60 days, and 600mg did everything 900mg did.*
- Two trials measured something people can feel. Every NMN group in that trial walked further in a 6-minute test than placebo, and Yoshino's team in Science found better muscle insulin response in 25 women over 10 weeks.*
- It's well tolerated across the studied range, from single 100mg doses up to 900mg a day.*
- The open question is tissue. Nobody has yet shown an oral dose lifting NAD+ inside human muscle or liver, and section 05 lays that out properly.
Section 01
What does NAD+ actually do?
The first is energy. Every cell turns food into usable fuel through a chain of reactions, and NAD+ is the carrier that moves electrons along that chain. Without it, those reactions stop. This is textbook biochemistry.*
The second is repair. Your DNA takes damage constantly, from sunlight, from ordinary metabolism, from living. A family of enzymes called PARPs finds those breaks and patches them, and they consume NAD+ as their raw material while they work. A second family, the sirtuins, needs NAD+ too. Both draw on the same pool.*
Which means the amount of NAD+ your cells have available isn't a minor detail. It is the shared budget that repair and energy production both spend from.
Where NMN comes in
Your cells don't store NAD+. They rebuild it constantly, and that rebuilding route runs through NMN. NMN is the last stop before NAD+, one enzyme step away.
An NMN supplement runs on that logic, and it's why the molecule became the focus of a research program rather than a passing trend.
Section 02
What is healthspan, and how is it different from lifespan?
Lifespan is how many years you get. Healthspan is how many of them you spend feeling good.
Medicine has been far better at extending the first than the second. Everything on this page is about the second one: energy, repair, and how well the machinery holds up as the years pass.
Section 03
How far has the NMN research actually got?
The lab most associated with this work belongs to David Sinclair at Harvard Medical School. It runs two separate lines, and they're worth keeping apart.
The NAD+ line, where NMN is the central molecule
Three papers built the case. Each one used NMN, and each restored something different in aging animals.
Aged mice given NMN recovered mitochondrial function toward young levels in about a week. Gomes published that in Cell in 2013, and it's the result that started the field.
4 years later the same lab turned to DNA repair. As NAD+ runs low, the enzymes that patch broken DNA get held up and the damage stacks. NMN freed them again, and repair activity came back in old mice. Li reported that in Science in 2017.
Then circulation. Das found in 2018 that NMN widened blood flow and improved endurance in aged mice.
Mitochondria, DNA repair, blood flow. Three different systems, one molecule, all restored in aging animals.
The other line, and it just reached human trials
The same lab has also been asking a harder question: whether aging itself can be reversed. In 2020 they restored vision in aged mice, and in mice with glaucoma, by resetting the epigenetic patterns inside their optic nerve cells. That work ran in Nature. 3 years later, in Cell, the lab set out what it calls the information theory of aging: that aging is driven by a loss of epigenetic information, and that restoring the information can reverse aspects of aging.
It didn't stay in the laboratory. A therapy built on that research cleared the FDA in January of this year, and starting in June it has been given to human patients in a Phase 1 trial for optic nerve conditions. It is the first time anyone has given a partial epigenetic reprogramming therapy to a person. Sinclair co-founded the company running it.
Two things worth being straight about, because most pages aren't. That therapy is a gene therapy injected into the eye, and it doesn't involve NMN. And every NMN result above was measured in mice. What links the two lines is a research program and a conviction that biological aging is something you can act on, not a shared molecule.
Section 04
What happened when they gave NMN to people
4 human trials so far. Here is what they measured.
- 80 Blood NAD went up Yi and colleagues, February 2023. 80 healthy middle-aged adults, 60 days. NAD rose significantly at 300, 600 and 900mg. 600 did everything 900 did.
- 6 min They walked further Same trial. Every NMN group covered significantly more ground in a six-minute walking test than placebo, and scored better on quality of life.
- ~25% Better muscle insulin response Yoshino and colleagues in Science, June 2021. 25 postmenopausal women, 250mg daily for 10 weeks, against placebo. The most rigorous trial in the field.
- 100 to 900mg Well tolerated across the range Every published trial reported oral NMN as well tolerated at the doses tested, from single 100mg doses up to 900mg daily.
Blood NAD rises. People perform better on a physical test. Muscle responds better to insulin. Those are early results from small trials, and they point the same way as 12 years of animal work.*
The two human trials this section rests on.
| Trial | Who | Dose | Length | What it found |
|---|---|---|---|---|
| Yi, 2023 | 80 healthy middle-aged adults | 300, 600 and 900mg | 60 days | Blood NAD+ rose at every dose, 600mg did everything 900mg did, and every NMN group covered more ground in a 6-minute walking test than placebo |
| Yoshino, 2021 | 25 postmenopausal women with prediabetes | 250mg | 10 weeks | Better muscle insulin response against placebo, published in Science |
Section 05
Is the NMN research any good?
"The human trials are short."
The trials are short. 60 days and 10 weeks. Which is exactly why the mechanism matters: NAD+'s role in energy production and DNA repair isn't a hypothesis waiting on a trial, it's established biochemistry, and the animal work has run long enough to show functional change. Short human trials are what an early field looks like, not what a failed one looks like.
"Blood NAD is not the same as NAD inside cells."
Correct, and worth understanding rather than glossing. Yi and colleagues measured serum. What that establishes is that oral NMN is absorbed and converted, which is the necessary first step. Measuring inside human muscle requires a biopsy, which is why almost nobody has done it.
"NAD+ drops 50 percent by age fifty."
That particular number is looser than the research behind it. What the research does show is a fall in human tissue, measured rather than assumed. Massudi tracked it in skin across the whole lifespan in 2012. Zhu measured it inside the living brain, published in PNAS in 2015. Two tissues, two teams, 3 years apart, and both watched it drop.
The direction isn't in doubt. Massudi found NAD+ in skin tracking downward with age in both men and women, and the drop was steep: adults aged 51 to 70 averaged around 60 percent less than adults aged 30 to 50. It falls, it keeps falling, and by the back half of life the gap is wide.
Talk to your healthcare provider before starting anything in this category if you take prescription medication, are pregnant or nursing, are managing a medical condition, or have a personal or family history of cancer.
Section 06
Does the bottle contain what the label says?
Two laboratories have bought NMN supplements off the shelf and measured what was inside. Their results are strikingly different, and one of the two was paid for by a company selling a competing ingredient, which nobody quoting it ever mentions.
The full comparison, and the six things to check on a certificate before you buy, are in how to tell whether your NMN actually contains NMN.
Section 07
Read next
Published so far. More are on the way.
- Does NMN really work? Start here if you're new to this. What the name means, whether it has anything to do with nicotine, what the trials measured, and what you should realistically expect to notice.
- NMN vs NAD+, what the difference actually is Why nobody sells NAD+ itself, what the human trials measured including the two 2026 head-to-heads that disagree, and the age-decline figure nobody can source.
- How to tell whether your NMN actually contains NMN Two laboratories, two very different answers, and the detail buried in the most-quoted study that reframes the whole statistic.
Section 08
Our NMN is backed by BatchProof™
Healthspan line NMN360™
Every batch is tested for how much NMN is actually in the capsule, by HPLC, the same method that caught other products coming up short. Scan the code on the bottle to see your lab specific batch report.
*Lot NMN251218 came back at 533.28mg against a 500mg label.
BatchProof™ is our verification system giving you instant access to the third-party lab test results for your specific batch. Don't Just Trust. Verify.
Section 09
Common questions
Is Dr David Sinclair's lab working on leading-edge research into reversing aging?
What does NAD+ actually do?
What is the difference between healthspan and lifespan?
Does NMN raise NAD+ levels in humans?
What dose did the research use?
Does NAD+ really fall by half by age fifty?
Is NMN legal to sell in the United States?
How do I check whether an NMN supplement contains what it claims?
Are there safety concerns with long-term NMN use?
When should I talk to a healthcare provider?
*These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease. This guide is for general information only and is not medical advice. Consult your healthcare provider before starting any supplement, particularly if you are pregnant, nursing, managing a medical condition, or taking medication.