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Peptide & Experimental

NMNH (reduced NMN)

Reduced NAD+ precursor from the vitamin B3 family, not authorized in the EU · Reduced nicotinamide mononucleotide, dihydronicotinamide mononucleotide, reduced NMN, NMN-H, NMNH-Ca, UthPeak

NMNH is the reduced form of NMN, that is, the same molecule in a more energy-rich form. In cells and mice it raises the NAD+ level considerably more strongly and faster than NMN or nicotinamide riboside. Since 2026 there has been a first placebo-controlled study in humans, still as a preprint and funded by the manufacturer.

In short

NMNH, reduced nicotinamide mononucleotide, is a new precursor of the coenzyme NAD+. In cell culture and mice it acts as a more powerful NAD+ booster than the well-known precursors NMN and NR and uses its own metabolic pathway to do so. In humans there is a single study: in 80 healthy adults, NAD+ in the blood rose dose-dependently over 90 days, without serious side effects. The catch: a preprint that has not been peer-reviewed, the manufacturer as sponsor, blood values only, and the results on biological age and fitness are exploratory. In the EU, NMNH is not an authorized food.

What it is

NAD+ is a coenzyme that every cell needs: for energy production in the mitochondria, as raw material for repair enzymes and for the sirtuins, which play a major role in aging research. The body builds it from precursors of the vitamin B3 family; the best known on the market are NMN and nicotinamide riboside, NR for short.

NMNH is the reduced form of NMN. Chemically this is a small difference, metabolically a large one: NMN is converted into NAD+, NMNH first into NADH, the energy-rich form of the coenzyme, which the cell can then process further into NAD+. NMNH was only described as an NAD+ precursor in 2021, almost simultaneously by a group around Zapata-Pérez and Houtkooper and independently by a group around Liu and Deng. This makes it one of the newest substances on the longevity shelf.

How it is supposed to work

The idea is simple: NMN and NR raise the NAD+ level in cells and animals only to a limited extent, according to a 2026 paper to about double. NMNH does not need the enzymes NRK and NAMPT, through which NR and the body’s own recycling run, but is processed directly by the enzyme NMNAT, thus bypassing a bottleneck of the classic precursors.

In liver cancer cells, NAD+ rose 5- to 7-fold under NMNH, while NMN at the same concentration had only a slight effect. In mice, liver NAD+ six hours after administration was 4-fold above control and 1.5-fold above the value after NMN; at the same time, NADH in the liver rose 3-fold. The group around Zapata-Pérez found a rapid and sustained rise in the blood in mice and more NAD+ in liver, kidney, muscle, brain, brown fat and heart, but not in white adipose tissue. According to the first author, the blood value remained doubled for at least 20 hours under NMNH, whereas under NMN it was back at baseline after 4 hours.

The first study in humans

In August 2026 the first controlled human study appeared as a preprint. 80 healthy adults aged 40 to 65 received either placebo or NMNH as a calcium salt at three levels, 125, 250 or 500 mg daily, for 90 days. The primary objective was safety, and that looked good: 6 mild adverse events, no serious ones, none treatment-related, no discontinuations.

The NAD+ level in whole blood rose dose-dependently. At the highest level it went from an average of 19.43 to 59.33 µM, while it remained practically unchanged on placebo. After a single dose, the peak occurred after 12 hours. This means the central mechanism has been measured in humans for the first time.

There were also exploratory endpoints: in the 500 mg group, biological age calculated from blood values fell by 5.18 years, while on placebo it rose by 2.62 years; the six-minute walking distance increased by 114 m, on placebo by 25 m, and quality of life in the SF-36 questionnaire improved in all 8 domains. Interesting signals for the next, larger study.

How it differs from NMN and NR

NMN and NR are the established NAD+ precursors and each has its own entry. Both have been studied far better in humans than NMNH, with several randomized trials in which NAD+ in the blood reliably rises, while hard clinical effects have so far remained thin. NMNH promises to achieve more in the rise itself.

One difference here is more than a matter of strength. In mouse liver cells, the reduced precursors NMNH and NRH altered metabolism more broadly and switched more genes than NMN and NR, including stress-related detoxification enzymes, without depleting glutathione. The authors speak of a pseudo-stress response. So NMNH is not simply a stronger NMN.

What users report

NMNH has recently been marketed, mainly in the US, and is touted in longevity circles as the next generation after NMN. Reports mostly revolve around more energy and well-being. Such impressions are uncontrolled and cannot be separated from expectation and daily form, but they show that the substance has arrived in the scene.

What is well supported

It is well supported that NMNH is a particularly effective NAD+ precursor. Two independent research groups have shown this in cell culture and in mice, and another 2026 paper has confirmed it in liver cells. The rise is faster and higher than with NMN and NR, it reaches several organs, and it runs via its own metabolic pathway.

Added to this now is the first finding in humans: in a randomized, double-blind study, the NAD+ level in the blood rose dose-dependently and significantly compared with placebo over 90 days, and the product was well tolerated. For a substance first described in 2021, this is a remarkably fast path from the laboratory to humans.

What the studies show

Li et al., medRxiv 2026 - the first human study

Randomized, double-blind, placebo-controlled, phase I, registered as NCT06889740. 80 healthy adults aged 40 to 65, 69 of them men, all of Asian origin, received placebo or NMNH at three levels for 90 days. Primary endpoint safety, met. NAD+ in whole blood rose dose-dependently, at the highest level from 19.43 to 59.33 µM, significantly compared with placebo. Exploratively, biological blood age, walking distance and quality of life improved. Preprint; the manufacturer supplied the product, and 7 authors are employed by it.

Zapata-Pérez et al., FASEB Journal 2021 - the first description

The paper describes the production of NMNH and shows in several cell lines a stronger and faster NAD+ rise than with NMN or NR, via a pathway without the enzymes NRK and NAMPT. In kidney cells, NMNH reduced damage after oxygen deprivation. In mice, NAD+ in the blood rose rapidly and sustainedly, and in six organs, not in white fat.

Liu et al., Journal of Proteome Research 2021 - metabolic profile

The second first description. NMNH raised NAD+ 5- to 7-fold in liver cancer cells and 4-fold in mouse liver. At the same time it inhibited glycolysis and the citric acid cycle, stopped cell division in cell culture and slowed growth; the body weight of the mice remained unchanged over 4 weeks.

Where the data stop

The human data rest on a single study, and it has not yet been peer-reviewed. It is small, lasted 90 days, included almost only men and exclusively Asian participants, and was funded by the manufacturer. NAD+ was measured in whole blood. Whether it also rises in muscle, brain or liver, as in animals, has not been studied in humans, and the authors point this out themselves. Biological age, walking distance and quality of life were exploratory endpoints without sample size planning; they generate hypotheses, not evidence. The advertising claim “five years younger” turns such a signal into a fact.

It is also open whether more NAD+ is always better. In cells, NMNH slowed glycolysis, the citric acid cycle and cell growth, and in liver cells it triggered a broad, stress-like gene response. With the related reduced precursor NRH, higher doses showed signs of toxicity in mice. Whether these effects are beneficial, neutral or harmful in the body, no one knows today. Long-term data and studies with hard endpoints are missing entirely.

Status, approval and legal

NMNH is authorized in the EU neither as a medicine nor as a novel food. Even for oxidized NMN, the European Commission has confirmed novel food status because consumption before May 15, 1997 has not been demonstrated; in 2026 EFSA assessed chemically produced β-NMN from one manufacturer as safe, but that applies only to NMN. For NMNH, neither an EFSA opinion nor an authorization could be found; it is therefore not legally marketable as a food supplement in the EU. In the US, the manufacturer relies on a self-declared GRAS status; a review by the FDA is not documented. NMNH is not on the doping list. We do not give dosage information; the amounts mentioned only describe the study.

Safety

In humans, NMNH has been studied over 90 days in 80 healthy adults, without serious or treatment-related side effects. Beyond that there is nothing: no data on pregnancy, breastfeeding or children, none on people with cancer, liver or kidney disease, and no interaction studies. Because NMNH slowed the growth of cancer cells in cell culture and broadly rewires cell metabolism, its preclinical profile is not as harmless as the name of a vitamin precursor suggests. There are no official upper limits for NMNH. Anyone who takes medication or has a medical condition should discuss this with their doctor.

BK-Score Hype far ahead of evidence

Human evidence3
Mechanism5
Safety data4
Hype gap3
Track record of use3

Evidence 3, because the human data come from a single randomized, double-blind phase I study that so far exists only as a preprint and was funded by the manufacturer: 80 healthy people, 90 days, NAD+ in whole blood dose-dependent, at the highest level from 19.43 to 59.33 µM (Li 2026, NCT06889740); biological age, walking distance and quality of life were exploratory. Mechanism 5, because the separate pathway via NMNAT and the strong NAD+ rise in cells and mice have been shown by two independent groups – liver cancer cells 5- to 7-fold, mouse liver 4-fold (Zapata-Pérez 2021; Liu 2021) – but in humans only the blood value has been measured, and the rewiring of glycolysis, the citric acid cycle and stress genes is not yet understood (Vinten 2026). Safety 4, because only 90 days in 80 healthy people have been observed under controlled conditions, without serious events, without long-term or interaction data. Hype 3, because the manufacturer turns the exploratory blood-age finding into “5 years younger”, although the NAD+ rise in the blood has actually been measured. Use 3, because NMNH has only recently been marketed, mainly in the US, and is not authorized in the EU. Direction open, because there is no clinical endpoint that speaks for or against a benefit.

The score rates the state of knowledge, not the substance. “Safety data 9” means well studied – not harmless.
Subjective assessment by Biohacking Kompakt based on published scoring rules – not a scientific rating and not a medical recommendation. Rules and all ratings (German)

Frequently asked questions about NMNH (reduced NMN)

What is NMNH?

NMNH is reduced nicotinamide mononucleotide, the more energy-rich form of NMN. The body converts it into NADH and then into NAD+. It was first described as an NAD+ precursor in 2021.

Is NMNH better than NMN?

For the rise in NAD+ in cells and mice, yes; there it was considerably stronger and faster. Whether this leads to more benefit in humans has not been studied; there is no head-to-head comparison with NMN in humans. In addition, NMNH alters cell metabolism more broadly than NMN.

Are there studies on NMNH in humans?

There is a single one, a placebo-controlled phase I study with 80 healthy adults over 90 days. NAD+ in the blood rose dose-dependently, and side effects were mild. The study has not yet been peer-reviewed and was funded by the manufacturer.

Does NMNH make you biologically younger?

In the human study, the biological age calculated from blood values fell in the highest dose group and rose on placebo. However, this was an exploratory endpoint in a small study without sample size planning. That is not enough as proof of rejuvenation.

Is NMNH permitted in Germany?

NMNH is not an authorized novel food in the EU and not a medicine. It may therefore not be sold here as a food supplement. It is not on the doping list.

Is NMNH safe?

Over 90 days, no serious side effects occurred in healthy adults. Long-term data are missing, as are data on pregnant women, sick people and interactions. In cell experiments, NMNH slowed metabolic pathways and cell growth, which still needs to be put into context.

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Information only, not medical advice and not a usage or dosage recommendation. Prescription-only and unapproved substances belong in the hands of a physician. Last updated: 2026-09-27.