NRH dosage and evidence
Written by Aaron CuhaReviewed Sep 2026
The short answer
In cells grown in a dish, NRH raised NAD 2.5 to 10-fold within an hour, more than NR or NMN at the same amount. It also reaches body tissues in mice. It has never been given to a person in a published study, and it is already sold to consumers.
Evidence grade for NRH: Limited. The rule: people have taken it in a published study, but fewer than 100 of them. The sum on this page: 1 completed trial, 65 people given it. A grade counts how much has been done to people, not whether it works.
- People given it
- 65
- Human studies
- 1
- Found nothing
- 0
Dose
No human dose established
Amounts that were given in studies sit in Human evidence on this page. None of them is a personal dose.
1 completed trial, 65 people given it
1 effects reported, 1 unwanted, by people using it, not a trial
Goal pages: Fat loss and metabolism
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.
NRH is a lab-made form of NR, a vitamin B3 cousin sold to raise NAD. In cells, it raises NAD harder than NR or NMN. It has never been tested in people. It is sold online anyway.
What people take it for
- Raising NAD more than NR or NMN can.
- Anti-ageing.
- More energy.
What studies in people showed
Nobody has tested this in people. There is no study of how the body handles it, and no safety study. In cells, it raised NAD 2.5 to 10-fold within an hour. In mice, it raised NAD in body tissues and protected the kidneys from a cancer drug. Its close cousin, NMNH, also slowed how cells burn sugar and stopped cells growing in a dish.
What people report
Reports, not study results
The good
- We have not collected user reports on this one yet.
The bad
- There is no human safety data, so nobody knows its side effects.
Where these come from: We have no user reports. Everything on this page is from cells and mice.
My bottom line
Strong in a dish, untested in people. I would not be the first human to try it.
An opinion, not a finding. I am a coach, not a doctor.
What it has been measured to do
Animal and lab work, not yet tested in people
Real results, but from animals or cells, not people. What works in a mouse often does not work the same way in a person. Nobody can patent this, so nobody would ever earn back the cost of a study in people. That is usually why there is none. The record on this one is set out below.
- Losing weight1 animal or lab study
35 of the 36 indexed goals have no study of any kind behind NRH
No study in people, animals or cells on this page reports a result for these. That does not prove NRH does nothing for them. It does mean anything you have heard about NRH and one of these did not come from a study cited here.
Show full evidence
What is NRH?
In cells grown in a dish, NRH raised NAD 2.5 to 10-fold within an hour, more than NR or NMN at the same amount. It also reaches body tissues in mice. It has never been given to a person in a published study, and it is already sold to consumers.
NRH is the reduced form of nicotinamide riboside, or NR. By a wide margin, it raises NAD harder than anything else in this batch. Every number behind that comes from cells in a dish or from mice.
The interest in it is real. NR has to be changed by enzymes called NRK1 and NRK2 before the body can use it, and that step is slow. NRH skips it. In 2019, two separate teams showed that NRH uses a different route to NAD, one that does not need NRK1. It gets turned into NMNH first. So the reduced forms are a separate branch of NAD making, not just a slightly better version of the same one.
In cells, NRH raised NAD 2.5 to 10-fold within as little as an hour. It beat NR and NMN at every matching amount tested. In mice, a shot into the belly raised NAD in tissues. A second team showed mice can absorb it by mouth, and it protected their kidneys from damage by the cancer drug cisplatin.
Against that: there is no published study of how the human body handles it. No published safety study in people. No published study in people of any kind. NRH is sold online as a supplement anyway. The sales copy usually quotes the cell result as if it were a human result.
There is also a reason for caution in this family. Its closest cousin, NMNH, raised NAD more than NMN. In the same experiments, it slowed the cell's main sugar-burning steps, stopped cells dividing, and held back cell growth. Raising NAD harder and faster is not clearly better. Nobody knows what the reduced forms do to a person.
How does NRH work?
Inside cells, an energy-using enzyme turns NRH into NMNH. That step does not need NRK1 or NRK2. Other enzymes then turn NMNH into NADH, which joins the NAD pool. Skipping the NRK step is the likely reason NRH beats NR, because NRK1 is the slow step for NR. Because it comes in as the reduced form, it also shifts the balance between NAD and NADH differently from NR and NMN. That is the least understood part of how it works, and the part that matters most for whether it is safe.
The state of the research
There is no human evidence for NRH of any kind. No study of how the body handles it, no safety study, no trial. That is the entire human record, and it is why this page has no human evidence section.
What exists is two separate 2019 papers, in cells and mice. They agree that NRH raises NAD faster and higher than NR or NMN, by a different enzyme route. Two teams confirming the same thing in the same year is real and worth saying plainly. It is also a fact about chemistry, not about people.
The product is sold in the gap between those two facts. Sales copy for NRH often quotes the 2.5 to 10-fold figure without saying it came from cells in a dish. It talks about being absorbed by mouth without saying that was measured in mice.
There is a specific reason not to assume stronger is better here. A third team studied NMNH, what NRH turns into first. It raised NAD more than NMN. At the same time, in a dish, it slowed the cell's main sugar-burning steps, slowed cell growth, and stopped cells dividing. A product that shifts the NAD to NADH balance hard is doing something to how cells make energy. In the one experiment that looked, it slowed it down. Whether that is harmful, neutral or helpful in a person is unknown, because nobody has looked.
Almost all consumer writing about this pathway blends three kinds of claim into one. Keeping them apart is most of the work. A blood marker claim says a product raises NAD in the blood. That is easy to show, and for several of these products it is simply true. A middle claim says it moves something between a blood marker and a symptom, such as how stiff the arteries are. A health claim says a person walks further, remembers more, gets fewer cancers or lives longer. A product can be solid on the first kind and have nothing at all on the third. That is where most of this pathway sits. No published study in people of any NAD booster has shown a real health benefit, with one exception on this list. That exception is nicotinamide in skin cancer. It works by helping sun-damaged skin repair its DNA, not through anything to do with ageing.
The evidence, in charts
Fig. 1a · how many people
65people, across 1 study in people cited here
| Study | People | Share |
|---|---|---|
| Nature Metabolism 2026 | 65 | 100% |
The whole total is one study of 65. Counts are the number of people each study on this page says it signed up. That includes studies that only watched people and gave nobody the compound. Studies still signing people up are left out, and only studies cited on this page are counted.
Fig. 1b · evidence mix
1 of 4 sources here is a study in people. The rest are not.
- Study in people · done in people125%
- Animal study · done in animals375%
Counted from the list of sources on this page. It counts only what we cite, so there may be more studies out there. A review counts once, however many studies it sums up.
Fig. 2 · evidence over time
The studies cover 3 different years, 2019 to 2026, counted from the list of sources 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 countries shown. This is what the law says, not a verdict on the science. See Legal status below for the full text and any notes.
Fig. 4 · how much does what
Nobody has tested different amounts in people
This chart would show how the effect changes as the amount goes up. For this compound, nobody has measured that in people. So we leave it empty. We will not borrow an animal chart and pretend it works the same in people.
Fig. 5 · what the molecule is
- Kind of compound
- Supplement
- Molecule weight
- About 256 Da for the reduced free base, against 255 Da for the nicotinamide riboside cation.
- Half-life
- Stated in words, not a numbersee the exact wording below
- Chain length
- None on file
Half-life as stated on file: No human pharmacokinetic study has been published, so no half-life in people can be stated. The mouse work used intraperitoneal injection and oral gavage and reported tissue NAD rather than compound clearance.
No amino acid sequence is on file for NRH, which is expected: a supplement is not built from amino acids.
The studies we cite
- Study in people2026The differential impact of three different NAD(+) boosters on circulatory NAD and microbial metabolism in humans
NRH itself was not tested here. This trial compared three other NAD boosters, and it sits on this page to show what real human data in the field looks like. 65 healthy adults took one of them for two weeks. Nicotinamide riboside and NMN both raised NAD in the blood by a similar amount. Plain nicotinamide did not keep it up. The authors think gut bacteria turn the first two into nicotinic acid, which is what actually does the work. Ten authors work for Nestle Research.
Included as the comparator for what human data in this field actually looks like. A randomised open-label placebo-controlled trial in 65 healthy adults over 14 days found that nicotinamide riboside and NMN comparably raised circulating NAD while plain nicotinamide did not do so chronically, and proposed a gut-microbial route through nicotinic acid. NRH was not one of the three compounds tested. Ten authors are employees of Nestle Research.
- Animal study2019Dihydronicotinamide riboside is a potent NAD(+) concentration enhancer in vitro and in vivo
In a dish and in mice. NRH raised NAD 2.5 to 10-fold in cells within as little as an hour, more than NR or NMN at every matching amount. A shot into the belly raised NAD in mouse tissues. Cells treated with it survived DNA-damaging drugs better, and it did not trigger signs of cells dying off. The lead author has patent interests in this area and helped found Metro International Biotech.
Cell culture and C57BL/6J mice. NRH raised NAD concentrations 2.5 to 10-fold over control in mammalian cells within as little as an hour, and exceeded NR and NMN at every equivalent concentration tested. Intraperitoneal injection raised tissue NAD in mice. It raised the NAD to NADH ratio in cells and liver without inducing apoptotic markers or significant lactate increases, and treated cells resisted death from NAD-depleting genotoxins. Cell lysates converted NRH to NMNH via an ATP-dependent kinase independent of NRK1 and NRK2. Declared conflicts: the corresponding author holds intellectual property related to NR and its derivatives, has filed a patent on this work with Cornell University, and is a consultant and co-founder of Metro International Biotech.
- Animal study2019A reduced form of nicotinamide riboside defines a new path for NAD(+) biosynthesis and acts as an orally bioavailable NAD(+) precursor
In a dish and in mice. A second team confirmed it. NRH raised NAD faster and more than NR in cells and mouse tissues, using a new route that does not need NRK1. Mice absorbed it by mouth, and it protected their kidneys from damage by the cancer drug cisplatin. The lead author's address is Nestle Research.
Independent confirmation from a second group. NRH acted as a faster and more potent NAD precursor than NR in mammalian cells and mouse tissues, used different enzymes and a new NRK1-independent pathway, was orally bioavailable in mice, and prevented cisplatin-induced acute kidney injury in mice. The corresponding author's address is Nestle Research.
- Animal study2021Reduced Nicotinamide Mononucleotide (NMNH) Potently Enhances NAD(+) and Suppresses Glycolysis, the TCA Cycle, and Cell Growth
In a dish and in mice. NMNH, what NRH turns into first, raised NAD more than NMN in cells and in mice. In the same experiments, it slowed the cell's main sugar-burning steps, stopped cells dividing and held back cell growth in a dish. Mouse weight did not change. Anyone calling the reduced forms just a stronger NR has to explain this.
The reason to be careful with this whole family. NMNH, the direct downstream metabolite of NRH, was a better NAD enhancer than NMN in cells and in mice, and in the same experiments inhibited glycolysis and the TCA cycle, induced cell cycle arrest and suppressed cell growth in vitro. Mouse body weight did not differ. Any claim that a reduced precursor is simply a stronger version of NR has to account for this.
Common questions
Has NRH been tested in people?
Yes. 65 people given it across 1 completed trial cited here, 0 of which found nothing. In cells grown in a dish, NRH raised NAD 2.5 to 10-fold within an hour, more than NR or NMN at the same amount. It also reaches body tissues in mice. It has never been given to a person in a published study, and it is already sold to consumers.
What is the NRH dosage?
No human dose established. Amounts that were given in studies sit in Human evidence on this page. None of them is a personal dose. 1 completed trial, 65 people given it
Is NRH FDA-approved?
Not an approved drug, and not a recognised supplement ingredient in the United States. Research-chemical and supplement sellers sell it with no published human safety data. The FDA has not reviewed it.
Is NRH better than NR?
At raising NAD in cells and mouse tissue, yes, clearly and by a wide margin. It uses a different enzyme route that does not need the NRK enzymes. Whether it is better in a person is unknown, because no person has been given it in a published study. Those are two different questions, and the first does not answer the second.
Has NRH been tested in humans?
No. There is no published study of how the human body handles it, no safety study and no trial. It is sold anyway.
Is NRH safe?
Unknown. The mouse work found no signs of cells dying off and no weight change. That is some comfort about gross poisoning in rodents over short periods, and nothing more. Its closest cousin, NMNH, held back cell growth and stopped cells dividing in a dish, in the same experiments where it raised NAD. That is a reason to want human safety data before taking it, not after.
Why do vendors quote a 10-fold NAD increase?
Because that number is real. It comes from cells in a dish, treated directly with the product. In people, 1000 mg a day of NR by mouth raised NAD in whole blood by about 142 percent over 8 weeks. That is the fair comparison, and it is a totally different kind of measurement. A jump in a dish is not what happens in a person.
What would change this page?
A published study of how the human body handles it, and whether it is safe. That is the minimum, and it does not exist for NRH or for NMNH. Until it does, everything on this page is cells and mice, and should be read that way.