Supplement: NMN en NR

What It Is

NAD+ (nicotinamide adenine dinucleotide) is a coenzyme every cell uses to turn food into usable energy and to run its repair and signaling enzymes. Its level drifts down with age across many tissues, and that decline is the rationale behind the whole precursor category. NMN and NR are two precursor molecules the body converts into NAD+, sold as capsules or powder to top the pool back up. Both are relatives of vitamin B3, and NR and NMN raise NAD+ more than an ordinary diet does.

How It Works

Built from vitamin B3, NAD+ powers the enzymes of energy metabolism and feeds repair systems such as the sirtuins and the PARPs. Two of those steps are settled: NAD+ falls with age, and the precursors raise it back up.

Anatomy of the Practice

1The rationale: NAD+ falls with age

NAD+ is central to energy metabolism and cellular repair, and its levels decline with age in many tissues. That decline is why the precursor category exists: the hope is that restoring NAD+ toward a younger level restores some of what falls with it. The decline itself is well described.

2What the precursors do in the blood

Taken by mouth, NR and NMN are absorbed and converted into NAD+, and human trials consistently measure a rise in blood NAD+ and its metabolites within weeks. This is the dependable, replicated part. The marker rises, and it rises in a dose-related way, a pharmacological effect that is not in dispute.

3From a marker to an outcome

In the human trials blood NAD+ rose while strength, insulin sensitivity, and aging markers stayed where they were. A higher number on a lab report is one thing. Whether the extra NAD+ reaches the tissues that matter and does useful work there is what the functional trials must settle, and so far they mostly have not.

An intravenous NAD+ drip delivers NAD+ by a different route but runs into the same limit, and it rests on even less controlled outcome evidence than the oral capsules. For where NAD+ decline sits among the drivers of aging, see the biology of aging; for the cell structures it helps power, see the mitochondria.

What It Does

People buy a daily capsule on a simple chain: the level drops with age, precursors lift it, so lifting it should slow aging. That chain rests on animal work, and the animal work is the strong part. In aged mice, restoring NAD+ improves metabolism, muscle, and healthspan, and the field holds some of the more reproducible results in aging biology.

The human evidence sorts into tiers, strongest first. Firmest is the raised NAD+ level itself. The weak point is the payoff people pay for: added up, the precursors have not moved glucose, lipids, or muscle strength in ordinary adults over 60. Between that firm marker and those null results sit two preliminary leads in narrow groups. Above everything sits the headline claim with no completed human trial behind it, that a precursor extends healthspan or lifespan.

The weak point is the payoff people pay for: added up, the precursors have not moved glucose, lipids, or muscle strength in ordinary adults over 60.

The Research & Studies

Everything here is based on the research we have collected and checked, sorted into groups and ordered with the strongest evidence first. Click any claim to open the studies behind it.

How it works

Oral NR and NMN reliably raise blood NAD+, dose-dependently (NMN tested at 300 to 900 mg a day)Strong

In plain terms

Taking NR or NMN by mouth reliably raises the level of NAD+ in the blood. This is the one effect the human evidence is solid about.

In detail

In a 2x6-week randomized double-blind crossover trial (Martens et al. 2018, Nat Commun), chronic NR supplementation in healthy middle-aged and older adults was well tolerated and effectively stimulated NAD+ metabolism. First-in-human pharmacokinetics (Trammell et al. 2016, Nat Commun) showed single oral NR doses raised the blood NAD+ metabolome dose-dependently. A dose-ranging NMN trial (Yi et al. 2023, GeroScience) found blood NAD+ rose significantly at 300, 600 and 900 mg/day versus placebo and baseline, highest at the two higher doses.

Who this may not transfer to:The rise in blood NAD+ is measured in both sexes across NR and NMN trials; it is a pharmacodynamic marker, so it does not by itself transfer to any clinical benefit.

The studies · 3

Martens et al. 2018, Nat Commun (NR elevates NAD+ in middle-aged and older adults) · Nat Commun

Trammell et al. 2016, Nat Commun (NR orally bioavailable in mice and humans) · Nat Commun

Yi et al. 2023, GeroScience (dose-dependent NMN trial) · GeroScience

NAD+ falls with age, the premise for supplementing, though restoring it has not been shown to reverse agingModerate · mixed

In plain terms

NAD+ tends to fall as we get older, which is the reason people take precursors to top it up. The decline is well described; whether reversing it helps is a separate question.

In detail

Reviews of NAD+ biology (Lautrup et al. 2019, Cell Metab) describe an age-related decline in NAD+ across tissues, with downstream effects on sirtuin and PARP activity, DNA repair and mitochondrial function. This decline is the mechanistic premise for NAD+ precursor use; the review frames restoration as a hypothesis to be tested, not an established anti-aging intervention.

Who this may not transfer to:The age-related NAD+ decline is described across tissues in both sexes; it is a biological rationale, not a population outcome.

The study · 1

Lautrup et al. 2019, Cell Metab (NAD+ in brain aging and neurodegeneration) · Cell Metab

Blood Sugar

Pooled across 8 trials in 342 adults, NMN did not move glucose, insulin, HbA1c or lipidsModerate · no effect

In plain terms

When all the NMN trials are added up, it did not lower blood sugar, insulin or cholesterol on average. The general metabolic benefit people expect did not appear.

In detail

A systematic review and meta-analysis (Chen et al. 2024, Curr Diab Rep) pooled eight RCTs totaling 342 middle-aged and older adults, 49% female and mainly non-diabetic, with NMN doses of 250 to 2000 mg/day over 14 days to 12 weeks. Random-effects meta-analyzes found no significant benefit on fasting glucose, fasting insulin, glycated hemoglobin, HOMA-IR or lipid profile.

Who this may not transfer to:The pooled null was in mostly non-diabetic middle-aged and older adults of both sexes, so it does not rule out an effect in metabolically impaired groups.

The study · 1

Chen et al. 2024, Curr Diab Rep (NMN on glucose and lipid metabolism meta-analysis) · Curr Diab Rep

NMN 250 mg a day for 10 weeks raised muscle insulin sensitivity in 25 prediabetic postmenopausal womenPreliminary

In plain terms

In postmenopausal women with prediabetes, ten weeks of NMN improved how well their muscle responded to insulin. It is one small trial in a specific group.

In detail

A 10-week randomized double-blind placebo-controlled trial (Yoshino et al. 2021, Science; n=25) in overweight or obese postmenopausal women with prediabetes found NMN 250 mg/day increased insulin-stimulated glucose disposal measured by clamp, raised muscle AKT and mTOR phosphorylation, and up-regulated muscle remodeling genes. Body weight, other metabolic measures and circulating markers were largely unchanged.

Who this may not transfer to:The trial enrolled only postmenopausal women with prediabetes; whether the muscle insulin-sensitivity effect transfers to men, to premenopausal women or to metabolically healthy people has not been tested.

The study · 1

Yoshino et al. 2021, Science (NMN increases muscle insulin sensitivity in prediabetic women) · Science

Muscle And Strength

Neither NMN nor NR improved muscle mass, grip strength or gait speed in adults over 60Moderate · no effect

In plain terms

Adding up the trials, NMN and NR did not improve muscle size, grip strength or walking speed in older adults. The strength and function claims did not hold up.

In detail

A systematic review and meta-analysis (Prokopidis et al. 2025, J Cachexia Sarcopenia Muscle) of RCTs in adults with mean age 60.9 to 83 found NMN had no significant effect on skeletal muscle index, handgrip strength, gait speed or the five-time chair-stand test, and narrative synthesis showed no benefit for knee-extension strength, SPPB or thigh muscle mass. NR was associated with a longer six-minute walk only in people with peripheral artery disease. The authors concluded current evidence does not support NMN or NR for preserving muscle mass and function.

Who this may not transfer to:The null applies to older adults of both sexes with mean age over 60; it does not address younger or athletic people.

The study · 1

Prokopidis et al. 2025, J Cachexia Sarcopenia Muscle (NMN and NR on muscle mass and function meta-analysis) · J Cachexia Sarcopenia Muscle

Counts once: this finding and 1 other here come from the same source, so they are one body of evidence, not separate confirmations.

Longevity And Mortality

No human trial has shown NAD+ precursors extend healthspan or lifespan; the striking results are in animalsModerate · mixed

In plain terms

The striking lifespan results are in animals. In people, no trial has shown these precursors slow aging or extend life.

In detail

A systematic review of NAD+ precursor trials (Gindri et al. 2024) catalogued outcomes across clinical conditions and identified no lifespan or aging endpoints, and a muscle meta-analysis (Prokopidis et al. 2025) found no functional benefit in older adults. The animal literature shows NAD+ restoration improving healthspan and, for related interventions, lifespan, but this has not translated to demonstrated human healthspan or lifespan benefit.

Who this may not transfer to:No human healthspan or lifespan endpoint has been measured in either sex; the extension results are in animals only.

The studies · 2

Gindri et al. 2024, Am J Physiol Endocrinol Metab (safety and effectiveness of NAD systematic review) · Am J Physiol Endocrinol Metab

Prokopidis et al. 2025, J Cachexia Sarcopenia Muscle (NMN and NR on muscle mass and function meta-analysis) · J Cachexia Sarcopenia Muscle

Counts once: this finding and 1 other here come from the same source, so they are one body of evidence, not separate confirmations.

Cardiorespiratory Fitness

NMN 600 to 1200 mg a day lifted sub-maximal aerobic capacity in 48 runners, while VO2max did not changePreliminary

In plain terms

In amateur runners who kept training, higher NMN doses improved their sub-maximal aerobic capacity, though their peak capacity did not change.

In detail

A six-week four-arm randomized double-blind trial (Liao et al. 2021, J Int Soc Sports Nutr; n=48, 40 men and 8 women) in recreationally trained runners found the medium (600 mg) and high (1200 mg) NMN groups improved oxygen uptake, percentage of VO2max, and power at first and second ventilatory thresholds more than placebo. VO2max, O2-pulse, VO2 relative to work rate and peak power were unchanged. The authors attributed the effect to enhanced skeletal-muscle oxygen utilization.

Who this may not transfer to:The trial ran in young and middle-aged recreationally trained runners, only 8 of 48 women, so transfer to untrained or older people is untested.

The study · 1

Liao et al. 2021, J Int Soc Sports Nutr (NMN and aerobic capacity in amateur runners) · J Int Soc Sports Nutr

Getting NAD+ Up, in Order

Ways to Do It

Match what you do to what you want. If the goal is the healthspan the animal work points at, the levers with human evidence are free and come first. If the goal is to raise NAD+ specifically, the precursors do that, though whether the higher level changes how you feel or age is not established. The precursors and any metabolic use are worth talking through with a clinician first.

1

Use the free levers that support NAD+ biologyFreeModerate

Exercise and not eating to excess most reliably support NAD+ and mitochondrial health in people. Both carry decades of human healthspan evidence the capsules lack. If slower aging is what draws you to precursors, start here, it is the intervention most likely to actually deliver.

2

Cover the dietary building blockFreeEasy

The body makes NAD+ from vitamin B3 in ordinary food: fish, poultry, meat, mushrooms, peanuts, and fortified grains all supply niacin and nicotinamide. Outright NAD+ shortage from diet is uncommon on a mixed diet, so for most people the base of the pool is already covered without any supplement.

3

Plain niacinamide, if you just want cheap B3$Easy

Nicotinamide (niacinamide) is a cheap, long-used form of vitamin B3 that also feeds NAD+. It does not raise NAD+ as much as NR or NMN, and it is not sold as anti-aging. If the aim is simply to cover B3 at low cost, it does that, and it has the longest safety record of any form here.

4

Nicotinamide riboside, the studied precursor with the cleaner status$$Easy

NR is the precursor with the most human pharmacology behind it and a clearer regulatory footing in the United States, where it is an accepted dietary ingredient. Trial doses run around 250 to 1000 mg a day. It raises NAD+ dependably; the functional benefits beyond that are not established.

5

Nicotinamide mononucleotide, with the regulatory wrinkle$$ to $$$Easy

NMN raises NAD+ as well, and it carries the two most interesting human leads: better insulin sensitivity in postmenopausal prediabetic women, and improved aerobic capacity in runners. Its US regulatory status is unsettled, it sits in a gray zone though it is widely sold. Doses in trials run about 250 to 900 mg a day.

6

For a specific metabolic goal, decide it with a clinician$$ to $$$Moderate

The lone clean positive result came from that same prediabetic group. For a diagnosed metabolic problem, decide it with the clinician tracking your numbers. Diet, movement, and any prescribed medication are what manage it; the pooled trials did not find an average glucose benefit from a precursor.

Go Deeper

• IV therapy and NAD+: the infusion version of the same idea, and how its outcome evidence compares with a daily oral precursor.
• The biology of aging: where NAD+ decline ranks among the drivers of aging, and how to read a marker that can move while the outcome does not.
• Rapamycin: the other longevity frontier with a strong animal record and early human aging data, and the same animal-to-human gap.
• Mitochondria: the cell's power plants that NAD+ helps run, and the reason energy is the mechanism most people have in mind here.

The Chinese Medicine View

NAD+ and its precursors are products of 20th-century biochemistry, isolated and synthesized in a laboratory, so the classical Chinese pharmacopoeia has no entry for them. No historical text assigns NMN or NR a channel, a temperature, or a flavor, and reading one back in would be invention. What the tradition offers instead is a way of thinking about aging and about building the body up.

These precursors target the reserve loss that comes with age. Chinese medicine has always reasoned about that loss, chiefly through the Kidney essence, the deep constitutional reserve it ties to growth, aging, and vitality. The tradition holds this reserve is largely fixed at birth and spent across a lifetime, conserved and supported but not simply refilled from a bottle.

Tonifying, bu, is the family of methods for building up a true deficiency, and its art is judging whether the person has one and can transform what is given. Giving more than the system can use does not build reserve; it stagnates. Yang Sheng, the cultivation of life, rests on moderation, movement, and conserving reserves. In this tradition a tonic is matched to the person, never handed to everyone alike.

Cautions For This Practice

Extra restraint

Everything to be aware of is here, in one place. This practice suits most healthy people; a few situations call for real care.

Well tolerated for weeks to months across 489 people, with only mild effects; longer use unstudied

A systematic review of NAD+ and NADH randomized trials across clinical conditions (Gindri et al. 2024, Am J Physiol Endocrinol Metab; 10 studies, 489 participants) found supplementation was well tolerated with a low incidence of side effects, the most common being muscle pain, headache, fatigue and sleep disturbance, and no serious health risks. Dedicated trials of NR (Martens et al. 2018) and NMN (Yi et al. 2023) likewise reported good tolerability over their study windows.Gindri et al. 2024, Am J Physiol Endocrinol Metab (safety and effectiveness of NAD systematic review)Martens et al. 2018, Nat Commun (NR well-tolerated)

The aging payoff is an animal result, so treat anti-aging use as experimental

The lifespan and healthspan gains are a mouse result. Taking NMN or NR to live longer is a self-experiment. Do not let a capsule crowd out the exercise and eating habits with real human healthspan evidence.

Short-term safety looks good, long-term is unstudied

Across the human trials, NR and NMN were well tolerated for weeks to a few months. Effects were mostly mild (nausea, headache, fatigue) with no serious adverse events reported. No trial has run past a few months, so multi-year safety is simply unstudied. Years is the timescale anyone taking them for aging has in mind.

A theoretical concern with cancer, still unresolved

NAD+ fuels the growth and repair machinery of all cells, including cancerous ones. Some laboratory work raises the question of whether pushing NAD+ up could feed an existing tumor. It has not been shown to happen in people and stays theoretical. Still, anyone with a current or recent cancer should clear NAD+ precursors with their oncologist first.

NMN sits in a regulatory gray zone

In the United States the FDA has taken the position that NMN is excluded from the dietary-supplement definition. The reason: it was authorized for study as a drug before it was marketed as a supplement. It is nonetheless widely sold, and enforcement has been inconsistent. This does not make NMN dangerous, but the usual supplement oversight is uncertain.

Kidney or liver disease, pregnancy, and medication overlap

These precursors are processed and cleared by the body like other nutrients, and the trials showing they are tolerated were mostly in reasonably healthy adults. Supplemental doses have not been studied in kidney or liver disease, pregnancy, breastfeeding, or alongside metabolic medication. In any of those cases, clear it with your clinician first.

Buy tested, and keep the dose in the studied range

Supplements are loosely regulated. An independent testing mark such as NSF or Informed Choice is the simplest proof the label matches the contents, it matters most for NMN. Keep the dose within the range the trials used; there is no established reason to exceed it, and more is not known to be better.

Start slow, be smart, read the research, and consult a professional if you have any concerns. This is here to inform your choice, not make it for you.

Common Questions

What is the difference between NMN and NR?

For raising blood NAD+, they are broadly interchangeable, and neither has a demonstrated advantage over the other. They differ in two side matters: NR carries the longer record of human pharmacology, and NMN the more interesting narrow leads. Their US legal standing differs too. Pick on those terms; the core effect is the same either way.