Section 01
What it's used for
Raising blood NAD+ levels
In clinical studies in people, standard doses of nicotinamide riboside have been shown to raise blood levels of NAD+, a molecule cells need to produce energy, by 40 to 90 percent compared with levels before treatment.
▸Clinical wording
- Clinically proven to increase blood NAD+ levels by 40-90% at standard doses
- Supports sirtuin activation and mitochondrial function — key aging pathways
- FDA GRAS status confirms a strong safety profile for long-term supplementation
Cellular energy production
Nicotinamide riboside is studied for improving the function of mitochondria, the energy factories inside cells, and for supporting how efficiently cells generate the energy they need for everyday processes and activity.
▸Clinical wording
- Improves mitochondrial function and cellular energy production
- Supports insulin sensitivity and healthy glucose metabolism
- Reduces inflammation markers associated with metabolic syndrome
Brain energy metabolism
Nicotinamide riboside is studied for supporting NAD+ levels in the brain and the energy metabolism of neurons, the brain's nerve cells, which rely on a steady energy supply to keep functioning normally each day.
▸Clinical wording
- Supports brain NAD+ levels and neuronal energy metabolism
- Preclinical evidence of neuroprotection in Alzheimer’s and Parkinson’s models
- May support cognitive function preservation during aging
Blood vessel effects: unproven so far
Blood vessel effects are an active research area in people, but no published trial has shown a clear benefit. The largest trial found no significant change in blood pressure or artery stiffness; a pilot study showed a non-significant trend.
▸Clinical wording
Nicotinamide riboside's effects on endothelial function and vascular health are an active area of human research, but no published trial has yet demonstrated a significant improvement. The largest human trial found no significant change in blood pressure or arterial stiffness, stating only that future trials should further assess these endpoints; a related trial designed to test blood pressure and arterial stiffness exists only as a published protocol with no results yet, and a small pilot study in peripheral artery disease reported a positive trend in endothelial function that did not reach statistical significance. This direction is discussed in vendor and community material, but a settled clinical finding of improved endothelial function or vascular health has not been published.
Liver protection research
Preclinical research in cells and animals, plus early studies in people, suggests nicotinamide riboside may have protective effects on the liver, though this evidence is still described as early and preliminary.
▸Clinical wording
- Preclinical and early clinical data show hepatoprotective effects
- Supports liver NAD+ levels and fatty acid oxidation
- May benefit non-alcoholic fatty liver disease management
Section 02
Mechanism of Action
A shortcut into the recycling route
- Work published in 2004 identified nicotinamide riboside as an NAD+ building block with its own dedicated enzymes.
- Those enzymes add a phosphate to make NMN, which a second enzyme family then converts into NAD+.
- This route bypasses the previously described Preiss-Handler pathway entirely.
- Cell studies with labelled compounds found one of these enzymes (NRK1) both necessary and rate-limiting.
▸Clinical wording
NRK1 and NRK2 phosphorylation into the NAD+ salvage pathway
Bieganowski and Brenner identified nicotinamide riboside as an unanticipated NAD+ precursor in yeast and cloned conserved nicotinamide riboside kinase (NRK) genes in both yeast and humans, defining a route to NAD+ that bypasses the Preiss-Handler pathway (Cell, 2004). The NRK enzymes phosphorylate NR to nicotinamide mononucleotide, which NMNAT enzymes then adenylylate to NAD+. In mammalian cell work using gain- and loss-of-function models together with isotope-labelled compounds, Ratajczak and colleagues found NRK1 to be both necessary and rate-limiting for the conversion of exogenous NR into NAD+ (Nature Communications, 2016).
Most swallowed doses stop at the liver
- In human cells only the nucleoside forms enter readily, while the phosphate forms are broken down outside first.
- That uptake was attributed to equilibrative nucleoside transporters, the general carriers for such molecules.
- In mice, injected nicotinamide riboside reached many tissues intact.
- Oral nicotinamide riboside in the same mice was largely converted to nicotinamide in the liver.
▸Clinical wording
Nucleoside transport and hepatic first-pass conversion
Nikiforov and colleagues reported that in human cells, besides nicotinamide and nicotinic acid, only the corresponding nucleosides readily enter, while nucleotides such as NAD and NMN are degraded extracellularly first (Journal of Biological Chemistry, 2011). Kropotov and colleagues attributed this uptake to equilibrative nucleoside transporters, showing ENT-mediated import of nicotinamide riboside into human cells (International Journal of Molecular Sciences, 2021). Isotope-tracer work in mice added a caveat: intravenous NR reached multiple tissues intact, whereas oral NR was largely metabolised to nicotinamide in the liver (Liu et al., Cell Metabolism, 2018).
Feeding the cell's maintenance enzymes
- In cultured human and mouse cell lines the compound raised NAD+ and the activity of two maintenance enzymes.
- Mice on a high-fat diet showed greater oxidative capacity in skeletal muscle, liver and brown fat.
- The same mice spent more energy and developed less obesity than untreated animals.
- The authors tie this to precursor supply, not to any direct receptor binding by the compound.
▸Clinical wording
Sirtuin activation and mitochondrial oxidative metabolism
In cultured mammalian cells (HEK293T, C2C12 myotubes, Hepa1.6), nicotinamide riboside raised intracellular NAD+ and increased the activity of the NAD+-dependent deacetylases SIRT1 and SIRT3 (Cantó et al., Cell Metabolism, 2012). In C57Bl/6J mice on a high-fat diet, the same treatment was accompanied by greater deacetylation of SOD2 and FOXO1, higher oxidative capacity in skeletal muscle, liver and brown adipose tissue, increased energy expenditure and reduced development of obesity. These observations tie precursor supply to sirtuin-dependent mitochondrial signalling rather than to any direct receptor interaction by NR itself.
A repair program in aged mice
- In aged mice the compound switched on a mitochondrial stress-repair response in muscle stem cells.
- The same 2016 study reported delayed ageing of neural and pigment stem cells and longer mouse life span.
- These are rodent observations, and the longevity results have not been reproduced in humans.
▸Clinical wording
Mitochondrial unfolded protein response in stem cells
In aged mice, nicotinamide riboside induced the mitochondrial unfolded protein response and prohibitin proteins in muscle stem cells, which was associated with restored function of those cells (Zhang et al., Science, 2016). The same study reported delayed senescence in neural and melanocyte stem cells, prevention of senescence in a dystrophic mouse model, and an increase in mouse life span. The authors framed this as evidence that conserving cellular NAD+ can reprogram dysfunctional stem cells; the findings are rodent observations and have not been reproduced as longevity outcomes in humans.
Human trials measured chemistry, not outcomes
- In twelve healthy adults, single oral doses raised the blood NAD+ metabolome dose-dependently, up to 2.7-fold.
- In twelve older men, 21 days raised muscle NAD+ markers and lowered circulating inflammatory signals.
- In those same men, muscle energy output, glucose tolerance and insulin sensitivity were unchanged.
- A six-week crossover trial in middle-aged and older adults reported tolerability and raised NAD+.
▸Clinical wording
Human NAD+ metabolome and inflammatory signature
Human data concern precursor pharmacology rather than clinical endpoints. In twelve healthy adults, single oral doses raised the blood NAD+ metabolome dose-dependently, up to 2.7-fold (Trammell et al., Nature Communications, 2016). In a placebo-controlled crossover trial in twelve older men, 21 days of NR elevated the skeletal muscle NAD+ metabolome and lowered circulating inflammatory cytokines, while muscle mitochondrial bioenergetics, glucose tolerance and insulin sensitivity were unchanged (Elhassan et al., Cell Reports, 2019). A six-week crossover trial in middle-aged and older adults reported tolerability and elevated NAD+ (Martens et al., Nature Communications, 2018).
Section 03
Biological Pathways
No data for this section yet.
Section 04
Dosage Information
| Route / system | Context | Range studied | Limitation |
|---|---|---|---|
| Oral — dose-response trial | 8-week randomised trial in overweight adults | 100, 300 and 1000 mg a day — about 1–14 mg/kg at 70–90 kg. Whole-blood NAD+ rose 22%, 51% and 142% in two weeks and held 8 weeks. | The trial measured the blood marker and no clinical outcome. A 142% rise in NAD+ is a fact about the lab test, not about the person taking the capsule. |
| Oral — metabolic trial | 12-week trial, 40 obese insulin-resistant men | 1000 mg twice daily — 2 g a day, about 22–29 mg/kg at 70–90 kg, for 12 weeks. | Insulin sensitivity, glucose handling, resting energy use, fat breakdown and body composition were all unchanged: at 2 g a day, nothing metabolic moved. |
| Oral — disease trials | Heart failure, Parkinson's, peripheral artery disease | Heart failure: 1000 mg twice daily. Parkinson's: 3000 mg a day for 30 days. Artery disease: 500 mg twice daily for 6 months. | The first two were sized for safety and report no benefit. The artery trial's walking gain — 17.6 m over placebo, one-sided 90% interval — barely registers. |
| Oral — authorised versus tested | US and EU clearances against the doses trials used | Cleared as a supplement ingredient up to 300 mg a day in the US and by EFSA. Trials went to 2 g a day, and 3 g a day for 30 days. | Regulators reviewed a fraction of the trial doses, and no trial ran past a few months — far short of the years people mean to keep taking it. |
| Intravenous | Commercial wellness clinics; retrospective chart review | 500 mg in 500 mL of saline over about 37 minutes, on four consecutive days, in 8 clients. | Paying customers looked at afterwards: no control group, no measure of benefit, no comparison with 500 mg swallowed. Five of eight felt tingling or cramps. |
Results
Syringe Fill Level (100u syringe)
Set positive values for: Recommended dose per kg.
Research Use Only. This information is for educational and research purposes only. Not intended for medical advice or self-medication.
Section 05
Protocols
- Protocol 01
NAD+ Restoration Protocol
Protocol for restoring cellular NAD+ levels using one of three interchangeable approaches: direct NAD+ administration, NMN supplementation, or Nicotinamide Riboside (NR). Choose ONE approach based on your budget, preferred route, and goals. NAD+, NMN, and NR all raise NAD+ levels — they are alternatives, not a stack. NAD+ levels decline ~50% between ages 40-60, contributing to aging, cognitive decline, and metabolic dysfunction. Restoring NAD+ supports DNA repair, mitochondrial function, sirtuin activation, and cellular energy production.
- Focus
- Anti-Aging
- Level
- Beginner
- Duration
- Ongoing
Section 06
Stability & Storage
Storing the product
Nicotinamide riboside is kept in a cool, dry place and sealed tightly, since it is sensitive to moisture. Refrigeration extends its shelf life further.
After opening
Once opened, containers are resealed promptly to limit moisture exposure. The commercial Niagen form carries a shelf life of 2 years when stored properly.
Section 07
Side Effects & Precautions
Generally well tolerated up to 2000 mg/day in clinical trials. Mild side effects may include nausea, fatigue, headache, and digestive discomfort. No serious adverse effects reported.
Section 08
Regulatory Status
FDA / United States
Cleared twice as a dietary ingredient
Two New Dietary Ingredient notifications went unchallenged (NDI 882 in 2015, NDI 1062 in 2018), and a separate GRAS notice (GRN 635, 2016) covers its use in food and drink up to 300 mg per serving.
European Union
Authorised as a Novel Food
Regulation (EU) 2020/16 authorised nicotinamide riboside chloride for food supplements at up to 300 mg a day; Regulation (EU) 2022/1160 later extended use to foods for special medical purposes and weight-control diets, up to 500 mg a day.
WADA
Not on the Prohibited List
NR does not appear anywhere in WADA's 2026 Prohibited List, under S0, S2 or any other category.
It is sold worldwide as a branded ingredient — chiefly Niagen and Tru Niagen — which is part of why its regulatory paper trail is unusually complete. A clean record in the US and the EU does not mean approval everywhere: some countries still treat NR as an unreviewed supplement ingredient. Check the current rules where you are before relying on either country's clearance.
Section 09
Research Studies
- [1]Discoveries of nicotinamide riboside as a nutrient and conserved NRK genes establish a Preiss-Handler independent route to NAD+ in fungi and humansBieganowski P, Brenner C. · Cell · 2004
- [2]NRK1 controls nicotinamide mononucleotide and nicotinamide riboside metabolism in mammalian cellsRatajczak J, Joffraud M, Trammell SAJ, et al. · Nature Communications · 2016
- [3]Pathways and subcellular compartmentation of NAD biosynthesis in human cells: from entry of extracellular precursors to mitochondrial NAD generationNikiforov A, Dölle C, Niere M, Ziegler M. · Journal of Biological Chemistry · 2011
- [4]Equilibrative nucleoside transporters mediate the import of nicotinamide riboside and nicotinic acid riboside into human cellsKropotov A, Kulikova V, Nerinovski K, et al. · International Journal of Molecular Sciences · 2021
- [5]Quantitative analysis of NAD synthesis-breakdown fluxesLiu L, Su X, Quinn WJ 3rd, et al. · Cell Metabolism · 2018
- [6]The NAD+ precursor nicotinamide riboside enhances oxidative metabolism and protects against high-fat diet-induced obesityCantó C, Houtkooper RH, Pirinen E, et al. · Cell Metabolism · 2012
- [7]NAD+ repletion improves mitochondrial and stem cell function and enhances life span in miceZhang H, Ryu D, Wu Y, et al. · Science · 2016
- [8]Nicotinamide riboside is uniquely and orally bioavailable in mice and humansTrammell SA, Schmidt MS, Weidemann BJ, et al. · Nature Communications · 2016
- [9]Nicotinamide riboside augments the aged human skeletal muscle NAD+ metabolome and induces transcriptomic and anti-inflammatory signaturesElhassan YS, Kluckova K, Fletcher RS, et al. · Cell Reports · 2019
- [10]Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD+ in healthy middle-aged and older adultsMartens CR, Denman BA, Mazzo MR, et al. · Nature Communications · 2018
Section 10
Frequently Asked Questions
It reliably raises blood NAD+ - 22%, 51% and 142% at 100, 300 and 1000 mg daily in an 8-week trial - but that is a change in a lab marker. When a trial tested a functional outcome directly, at 2 g a day for 12 weeks in insulin-resistant men, insulin sensitivity, glucose handling, energy use, fat breakdown and body composition were all unchanged.
Both are NAD+ precursors that converge on the same pathway: NR is phosphorylated to NMN by NRK1/2 inside the cell, and NMN is then converted to NAD+ by NMNAT enzymes. NR is the more established regulatory case - it holds FDA GRAS status as a supplement ingredient with a clearance up to 300 mg/day recognised in the US and by EFSA - while research suggests much of an extracellular NMN dose is first broken down to NR by the enzyme CD73 before cells take it up, which is why the two compounds show overlapping effects.
Trials report it as generally well tolerated up to 2000 mg a day. Reported mild effects include nausea, fatigue, headache and digestive discomfort, and no serious adverse effects have been reported in the published human trials.
Human trials range from 100 mg to 3000 mg a day: 100-1000 mg in dose-response work, 2 g daily for 12 weeks in insulin-resistant men, and 3 g daily for 30 days in a Parkinson's trial. Regulatory clearance covers only up to 300 mg a day in the US and EU, and no trial has run longer than a few months.
No trial has shown that it does. The largest human trial found no significant change in blood pressure or arterial stiffness and called for further study rather than reporting a benefit; a small pilot in peripheral artery disease saw a trend toward better endothelial function that did not reach statistical significance, and a related trial designed to test blood pressure exists only as a published protocol with no results yet.
No - both are forms of vitamin B3 but they enter the NAD+ pathway differently. Niacin (nicotinic acid) is converted through the Preiss-Handler pathway, ordinary nicotinamide is recycled through the NAMPT-driven salvage pathway, and nicotinamide riboside uses a separate route via NRK1/2 kinases, identified specifically because it bypasses Preiss-Handler.
No interaction study between nicotinamide riboside and apixaban (Eliquis) or other blood thinners has been published. This is an unanswered question, not a documented safe combination.