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.*

That is settled biochemistry, not marketing, and it is the reason 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.

Section 01

NAD+ has two jobs, and both of them matter

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 is not a minor detail. It is the shared budget that repair and energy production both spend from.

Where NMN comes in

Your cells do not store NAD+. They rebuild it constantly, and that rebuilding route runs through NMN. NMN is the last stop before NAD+, one enzyme step away.

That is the logic of an NMN supplement, and it is why the molecule became the focus of a research program rather than a passing trend.

Two jobs, one shared pool. NMN is the raw material your cells rebuild that pool from.

Section 02

Healthspan is not the same thing as 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

The research is further along than most people realize

The lab most associated with this work belongs to David Sinclair at Harvard Medical School. It runs two separate lines, and they are 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 is the result that started the field.

Four 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. Three 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 did not 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 are not. That therapy is a gene therapy injected into the eye, and it does not 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.

Two research lines, twelve years. Only one of them has reached a human patient, and it is not the NMN line.

Section 04

What happened when they gave NMN to people

Four human trials so far. Here is what they measured.

80 Blood NAD went up Yi and colleagues, February 2023. Eighty healthy middle-aged adults, sixty 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. Twenty-five postmenopausal women, 250mg daily for ten 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 twelve years of animal work.*

Section 05

Three fair objections, answered straight

"The human trials are short."

They are. Sixty days and ten weeks. Which is exactly why the mechanism matters: NAD+'s role in energy production and DNA repair is not a hypothesis waiting on a trial, it is 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, three years apart, and both watched it drop.

The direction is not 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.

Circle area is the measured NAD+ level in human skin. The oldest band is five people and is drawn weaker for that reason.

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

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?

Yes, and the work has now reached people. His lab at Harvard Medical School restored vision in aged mice, and in mice with glaucoma, by resetting the settings inside their optic nerve cells, published in Nature in 2020. Three years later in Cell the lab argued that aging is driven by a loss of that cellular information, and that the information can be put back. 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 trial for optic nerve conditions. It is the first time anyone has given a treatment of this kind to a person. Sinclair co-founded the company running it. Separately, his lab has published a long body of work on NAD+, and NMN is the central molecule there, used to restore mitochondrial function, DNA repair and blood flow in aged mice. The therapy now in trials is delivered into the eye and does not involve NMN.

What does NAD+ actually do?

Two things. It is the carrier that moves electrons through the reactions your cells use to turn food into usable energy, and it is the raw material PARP enzymes consume when they repair breaks in your DNA. A second family of enzymes called sirtuins also depends on it. Both of those roles are established biochemistry rather than recent findings.

What is the difference between healthspan and lifespan?

Lifespan is how many years a person lives. Healthspan is how many of those years are spent in good health. Medicine has been more successful at extending the first than the second, which is why researchers began using a separate term for it.

Does NMN raise NAD+ levels in humans?

Yes, in blood. Yi tested eighty healthy middle-aged adults over sixty days in 2023, at 300, 600 and 900mg a day, and NAD went up at every dose. That reading came from serum, the fluid around your cells, which tells you the NMN is being absorbed and converted. Checking inside muscle means taking a biopsy, which is why almost nobody has done it.

What dose did the research use?

Published human doses run from 100mg to 900mg daily. Yi and colleagues found in February 2023 that blood NAD rose at 300, 600 and 900mg, with no additional gain above 600mg. Yoshino and colleagues used 250mg daily for ten weeks. None of this is a dosing recommendation, and anyone taking medication or managing a health condition should speak with their own clinician first.

Does NAD+ really fall by half by age fifty?

NAD+ does fall with age in human tissue. Massudi measured it in skin across the whole lifespan in 2012 and the drop was steep: adults aged 51 to 70 averaged around 60 percent less than adults aged 30 to 50. Zhu found the same direction inside the living brain, published in PNAS in 2015. The specific claim that it halves by age fifty is looser than the data behind it, since the group showing that drop averages 63. The decline itself is real, and it has now been measured in two separate tissues by two separate teams.

Is NMN legal to sell in the United States?

Yes. The FDA confirmed in letters dated September 29, 2025 that NMN is not excluded from the dietary supplement definition, and sent confirming letters to two ingredient suppliers on December 2, 2025. A New Dietary Ingredient notification is still required. Several widely read pages still describe NMN as banned, which has been out of date since late 2025.

How do I check whether an NMN supplement contains what it claims?

Ask for the certificate of analysis matching the lot number printed on your bottle, and check that it reports NMN content in milligrams for the finished capsule rather than purity of the raw ingredient. A certificate with no lot number, or one that does not match your bottle, describes a batch you did not buy.

Are there safety concerns with long-term NMN use?

Every published human trial reported oral NMN as well tolerated at the doses tested. Long-duration data does not exist yet, because the longest trials run to sixty days and three months. Roos, writing in 2021 with no commercial interest declared, raised a theoretical concern that because some cancer drugs work by stripping NAD+ out of cells, adding it back over years might in principle feed tumor growth. That is a hypothesis rather than something anyone has observed, and it is why anyone with a personal or family history of cancer should talk to their clinician first.

When should I talk to a healthcare provider?

Before starting any supplement 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. Also if you are considering a supplement in place of care you are already receiving.

*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.