Nicotinamide Riboside dosage and evidence
Written by Aaron CuhaReviewed Sep 2026
The short answer
A well-studied NAD+ precursor that reliably raises NAD+ in humans. Raising the molecule is proven; the mouse lifespan programme that tested it found no effect.
- People given it
- 90
- Human studies
- 3
- Found nothing
- 1
Dose
Approved medicine. No human dose established for unlabelled uses
Labeled amounts sit on the prescribing information. This page records what trials measured, not a personal dose.
Sold as a supplement; not an approved drug
5 effects reported, 3 unwanted, 2 wanted, by people using it, not a trial
In plain English
In plain English, from Aaron
This is how I would explain it to a friend. The evidence, with the numbers, is further down the page.
Nicotinamide riboside is a form of vitamin B3 that your body turns into NAD+. Of all the NAD boosters, this one has the best proof that it raises the number. It is sold as a supplement, often under the name Niagen. It is not an approved drug.
What people take it for
- Slowing down ageing.
- More energy and better recovery.
- Protecting the brain as they get older.
- Raising an NAD+ number they saw on a test.
What the trials actually showed
Raising the number is proven. In a small human pilot, the pill raised blood NAD+ up to 2.7 times. Six weeks of it in middle aged and older adults was well tolerated and raised NAD+. An 8 week trial found more dose meant more NAD+. Then the question that matters. Does a higher number do anything? The US government's mouse lifespan programme tested it. The mice did not live longer, male or female. The authors said they had expected it to work. In people there is one real result. 90 patients with clogged leg arteries took it for six months. They walked 17.6 metres farther in six minutes than the placebo group. That is one study in sick people. It is not proof of anything for a healthy person. Nobody has shown this pill slows ageing in a person.
What people report
Reports, not trial results
The good
- Most people say they feel nothing bad on it.
- Some report a small lift in energy.
The bad
- Nausea, flushing, leg cramps and easy bruising. These show up in the trial side effect lists and are mild.
- A lot of people feel no change at all.
- It is expensive for a vitamin.
Where these come from: The side effect list is from the trial safety tables. The energy and no-change reports are from longevity forums and sites that pool user reviews. Those are not from a trial.
My bottom line
This is the best NAD booster at doing the one thing it is sold on, and the mice it was tested on did not live longer. I would not take it to slow ageing.
An opinion, not a finding. I am a coach, not a doctor.
What it has been measured to do
Measured in people
Goals Nicotinamide Riboside has been measured for in a human being, most people first. Counts come from the study lines on this page and deliberately undercount.
- Getting stronger90 people · 1 study
- Cell energy and mitochondriano headcount stated · 4 studies · 1 found nothing
- Blood sugar and insulinno headcount stated · 1 study · 1 found nothing
- Liver fat and liver healthno headcount stated · 1 study
Measured in animals or cells, not yet in people
Real results that answer a different question from a trial. Where a human trial is missing on a compound nobody can patent, the reason is usually that no sponsor would ever recover the cost of running one.
- Living longer1 preclinical study
What people using it report
Uncontrolled and self-selected, so it cannot show that anything works. It is still the best guide on this page to what people actually do with Nicotinamide Riboside, what they expect, and what goes wrong. The full account, including the negative reports, is below.
29 of the 36 indexed goals have no study of any kind behind Nicotinamide Riboside
No trial, no animal work, no cell work on this page reports a result for these. That is an absence of evidence rather than evidence of absence, but it does mean anything you have been told about Nicotinamide Riboside and one of these did not come from a study cited here.
When this earns a spot
Same NAD-precursor lane as NMN. Human trials exist and are mostly biomarker and safety work, not mortality. It does not matter as a floor-list vitamin.
Bloodwork that belongs beside the bottle
Optional metabolic panel. Compare the NMN page.
No required blood marker on this compound. That is stated on purpose.
Default retest window: 90 days. If the named marker did not move, stop.
- Do not read a liver enzyme bump as 'detox'.
- Stacking NR with NMN is two receipts, not a better design.
Reading the number
Same honesty as NMN. If nothing you can name moved, stop.
What people typically order
No required marker. Product identity still matters.
Show full evidence
Overview
A well-studied NAD+ precursor that reliably raises NAD+ in humans. Raising the molecule is proven; the mouse lifespan programme that tested it found no effect.
Nicotinamide riboside is a form of vitamin B3 that the body converts into NAD+, the coenzyme central to energy metabolism and cellular repair. Human trials show it safely and reliably raises NAD+ levels, and it is one of the most studied NAD+ precursors, sold as a supplement (for example Niagen). What it raises and what it achieves are different questions: the NIA Interventions Testing Program tested it in genetically heterogeneous mice and found no lifespan effect in either sex, in a report whose authors noted this came despite data suggesting it would work. Raising NAD+ is well demonstrated. That this lengthens life is not.
Mechanism of action
Converts to NAD+ through the salvage pathway, restoring NAD+ that declines with age and supporting mitochondrial and repair enzymes.
Human evidence
NR reliably raises blood NAD. The mouse lifespan programme found no effect. Human function results are sparse: one modest walk-distance gain in peripheral artery disease, and a careful insulin-sensitivity trial that was null.
- Trammell 2016 and Martens 2018: oral NR raises blood NAD in people and was well tolerated over 6 weeks.
- Conze 2019: 8-week dose-ranging trial in healthy overweight adults. Safe, dose-dependent NAD rise. No benefit endpoint.
- Dollerup 2018: 40 obese men, 2000 mg/day for 12 weeks. Clamp insulin sensitivity and body composition did not improve.
- NICE 2024: 90 patients with peripheral artery disease, 6 months. Six-minute walk +17.6 m versus placebo.
- NIA Interventions Testing Program: NR did not extend mouse lifespan in either sex.
What this does not tell you: Raising NAD is easy to show and is not the same as a person living longer or handling sugar better. The walk-distance result is in people with poor leg circulation, not in healthy agers. No human lifespan trial exists.
The evidence, charted
Fig. 1a · evidence scale
90people, across 1 human study cited here
- 2024 · Nature Communications90100%
The whole total is one study of 90. Counts are the enrollment each human citation on this page states, which includes observational cohorts where nobody was given the compound. 4 further human citations state no participant count and are not counted here. Studies still recruiting are excluded, and only studies cited on this page are counted.
Fig. 1b · evidence mix
5 of 6 citations here are human work, the rest is not.
- Human · given to people583%
- Animal · given to animals117%
Counted from the citation list on this page, typed as this page types it. It understates any literature larger than the sources we cite, and a review counts once however many studies it covers.
Fig. 2 · evidence over time
Evidence spans 5 distinct years, 2016 to 2024, counted from the citation list on this page.
Fig. 3 · legal status at a glance
US
Not approved
UK
Not approved
AU
Not approved
CA
Not approved
Not approved in any of the four jurisdictions shown. A jurisdiction's classification is a regulatory fact, not a verdict on the science; see Legal status below for the full text and any notes.
Fig. 5 · molecular identity
- Modality
- Supplement
- Molecular weight
- 255.2 Da
- Half-life
- Stated in words, not a number
- Sequence length
- None on file
see the exact wording below
No amino acid sequence is on file for Nicotinamide Riboside, which is expected: a supplement is not built from residues.
Key studies & citations
- Animal202117-a-estradiol late in life extends lifespan in aging UM-HET3 male mice; nicotinamide riboside and three other drugs do not affect lifespan in either sex
NIA Interventions Testing Program: nicotinamide riboside at 1000 ppm from 8 months did not increase lifespan in either sex. The authors note this came despite data suggesting it would be effective.
- Human2016Nicotinamide riboside is uniquely and orally bioavailable in mice and humans
Swallowing this form of vitamin B3 really does raise NAD in the blood. In a small human study the level rose by up to nearly three times. That single fact is what the entire NAD supplement industry is built on. Raising a level in the blood is the start of an argument, not the end of it. Nobody in this study got healthier.
Oral NR raised blood NAD+ up to 2.7-fold in a human pilot and showed superior hepatic NAD+ kinetics in mice.
- Human2018Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD+ in healthy middle-aged and older adults
Six weeks of it was comfortable to take, and it lifted NAD as expected. Adults in middle age and older each did a stretch on the supplement and a stretch without it. What was measured was body chemistry. No symptom, no performance test and no disease outcome was looked at here.
Randomized crossover trial: 6 weeks of NR was well tolerated and effectively stimulated NAD+ metabolism.
- Human2019Safety and metabolism of long-term administration of NIAGEN (nicotinamide riboside chloride) in a randomized, double-blind, placebo-controlled clinical trial of healthy overweight adults
Eight weeks of it was safe in healthy overweight adults, and larger doses raised NAD further. Half the people got the supplement and half a dummy, without knowing which. The trial was built to check safety and find a dose, and that is what it answered. It was not built to show a benefit, and it did not show one.
8-week dose-ranging RCT supporting safety and dose-dependent NAD+ elevation.
- Human2024Nicotinamide riboside for peripheral artery disease: the NICE randomized clinical trial
For the first time, this supplement changed something a person could actually do. 90 patients with poor circulation in their legs took it for six months. They could walk about 17.6 metres further in six minutes than the dummy group, which is around 20 extra paces. That is modest, and it is real. It is also the only result this compound has that is about function rather than chemistry.
90 patients: 6 months of NR improved 6-minute walk distance by 17.6 m versus placebo, a first functional outcome.
- Human2018A randomized placebo-controlled clinical trial of nicotinamide riboside in obese men: safety, insulin-sensitivity, and lipid-mobilizing effects
The careful metabolic test in obese men was null. 40 sedentary men with a BMI over 30 took 1000 mg twice a day, or a dummy, for 12 weeks. Insulin sensitivity by clamp did not improve. Fuel use, body composition and liver fat did not improve. It was safe. Raising a pathway in a mouse and changing insulin in a man were different projects.
40 obese insulin-resistant sedentary men, BMI over 30, aged 40 to 70, randomised to NR 1000 mg twice daily or placebo for 12 weeks. Insulin sensitivity by hyperinsulinaemic euglycaemic clamp, endogenous glucose production, glucose disposal, resting energy expenditure, lipolysis and body composition did not improve. Safe. NCT02303483.
What users report
Self-reported experiences, not evidence. Nothing below was measured under controlled conditions, and reports like these cannot separate a real effect from placebo, from the training or diet change that accompanied it, or from what the product actually contained. They are here because knowing what people describe, including what goes wrong, is worth reading alongside the studies.
- The most common report by a wide margin is that nothing noticeable happened. People describe months of use, amounts from a few hundred milligrams up to about 2 g a day, and combinations with other longevity supplements, with no change in what they were tracking including blood pressure.
- The explanations people offer each other for that are dose and age, with a repeated suggestion that any effect would only show in people over a certain age or with an existing problem, which is offered as speculation rather than supported in the threads.
- In testosterone and men's health discussion it is largely dismissed on cost rather than debated on effect, with the argument that oral doses are converted in the liver anyway so that cheap plain niacinamide reaches the same endpoint for a fraction of the price.
- An observation raised in passing is that a manufacturer suggesting a break after a month implies side effects are being reported somewhere, which nobody in the threads is able to resolve.
- Favourable accounts exist but are individual and are not accompanied by measurements. Side effect discussion is thin, which in a supplement forum is an absence of complaints rather than evidence of safety.
Sources: ExcelMale NAD threads read directly, plus LongeCity personal experience threads reached through site-restricted search extracts because that board timed out on direct fetch from this environment, September 2026. Nothing above is attributed to any specific post and no post is reproduced.
Frequently asked questions
Has Nicotinamide Riboside been tested in people?
A well-studied NAD+ precursor that reliably raises NAD+ in humans. Raising the molecule is proven; the mouse lifespan programme that tested it found no effect. 3 completed trials, 90 people given it. 90 people given it across 3 completed trials. 1 found nothing.
What is the Nicotinamide Riboside dosage?
Approved medicine. No human dose established for unlabelled uses. Labeled amounts sit on the prescribing information. This page records what trials measured, not a personal dose. Sold as a supplement; not an approved drug
Is Nicotinamide Riboside FDA-approved?
Sold as a supplement; not an approved drug
Is NR better than NMN?
Both raise NAD+. NR has more published human safety and NAD+ data and a clearer supplement status, while NMN's US regulatory status is contested. Longevity benefits for either are unproven.
Latest reading on Nicotinamide Riboside
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