Nicotinamide riboside
NR raises blood NAD in trials. In obese men it did not improve insulin sensitivity, and in older adults it did not preserve muscle mass or function. In a 52-week trial in early Parkinson disease, symptom scores worsened more on NR than placebo. No trial measured lifespan. Short trials report adverse events similar to placebo.
Add to Bio HackChecked 2026-11-09
- Status
- Sold in the US as a dietary supplement ingredient. No FDA approval as a drug.
- Also called
- NR, nicotinamide riboside chloride, NIAGEN, Tru Niagen, NAD+ precursor, vitamin B3 riboside
- Taken for
- slowing aging, longer life, NAD levels, energy, muscle, insulin sensitivity, brain health, Parkinson disease, heart health, biological age
Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on
Shown to help2
Reported risks1
- LimitedOne trial found motor and non-motor symptoms worsened more on NR than placebo in early Parkinson disease.How often is not known
What people take it for, and what was found
Shown to help2
Blood NAD levels
Shown to raise blood NAD in adults, by 22 to 142% depending on dose. A rise in NAD measures uptake, not health.
The numbers and sources
- Effect
- In a 6-week crossover trial, NR raised NAD in blood cells by about 60% over placebo [1]. Doses of 100, 300 and 1,000 mg a day raised whole-blood NAD by 22%, 51% and 142% within 2 weeks, and the rise held for 8 weeks [2]. In older adults with mild cognitive impairment, blood NAD rose 2.6-fold on 1 g a day [3]. A systematic review of 33 human studies found oral NR and NMN consistently raised NAD-related metabolites [4].
- Population
- 24 healthy middle-aged and older adults, mean age 65 [1]; overweight adults [2]; 20 older adults with mild cognitive impairment over 10 weeks [3]; 33 human studies, 28 randomized [4].
- Sources
- [1], [2], [3], [4]
- Caveats
- A rise in NAD is a measure of uptake, not a health outcome. Trial [2] was funded by ChromaDex, the maker of NIAGEN. Two of its authors were ChromaDex employees and the third is ChromaDex's chief scientific adviser.
Biological age markers
One small trial found lower epigenetic age on two clocks in an exploratory analysis in older adults with mild cognitive impairment.
The numbers and sources
- Effect
- In an exploratory analysis, NR was linked to a modest rise in global DNA methylation and a lower epigenetic age on the PhenoAge and GrimAge clocks [3].
- Population
- 20 older adults with mild cognitive impairment over 10 weeks [3].
- Sources
- [3]
- Caveats
- An exploratory outcome in a 20-person pilot. Cognition did not change in the same trial [3].
Not shown to help5
Muscle and physical function
Not shown to preserve muscle mass or function in adults over 60. One trial found a longer six-minute walk in peripheral artery disease.
The numbers and sources
- Effect
- A meta-analysis of randomized trials in adults over 60 found no support for NR or NMN preserving muscle mass or function. NR was linked to a longer six-minute walk in peripheral artery disease, and to lower SPPB scores and slower chair stands in mild cognitive impairment [5]. In the peripheral artery disease trial, six-minute walk changed by +7.0 m on NR and -10.6 m on placebo, a difference of +17.6 m (90% CI +1.8 to +∞) at 6 months [6].
- Population
- Randomized trials in adults with mean ages of 60.9 to 83 [5]; 90 people with peripheral artery disease for 6 months [6].
- Sources
- [5], [6]
- Caveats
- The walking result is one trial with a one-sided interval. ChromaDex supplied the NR and placebo for it [6].
Insulin sensitivity and metabolism
One trial found no change in insulin sensitivity, energy expenditure or body composition in men with obesity and insulin resistance.
The numbers and sources
- Effect
- Over 12 weeks at 2,000 mg a day, NR did not improve insulin sensitivity, glucose production or glucose disposal measured by clamp. Resting energy expenditure, fat oxidation and body composition did not change [7].
- Population
- 40 sedentary men with obesity and insulin resistance, aged 40 to 70 [7].
- Sources
- [7]
- Caveats
- One investigator-initiated trial, in men only [7].
Parkinson disease
One trial found symptom scores worsened slightly more on NR than placebo over a year in early Parkinson disease, below the clinically important threshold.
The numbers and sources
- Effect
- Over 52 weeks, the total MDS-UPDRS score rose by 2.45 points on NR and fell by 0.27 on placebo, an adjusted difference of 2.72 points (95% CI 0.47 to 4.98) favoring placebo. Non-motor symptom scores also worsened more on NR (difference 4.22 points, 95% CI 1.07 to 7.37). Three other key secondary outcomes, including dopamine transporter imaging, did not differ [8].
- Population
- 410 people with Parkinson disease diagnosed within 2 years, randomized to 500 mg twice daily or placebo at 11 centers in Norway [8].
- Sources
- [8]
- Caveats
- One phase 3 trial. The difference is smaller than the 5.2-point threshold the trial set for clinically important worsening [8].
Memory and cognition in mild cognitive impairment
Small trials found no change in cognition over 10 to 12 weeks in older adults with mild cognitive impairment.
The numbers and sources
- Effect
- Cognition scores did not change over 10 weeks on 1 g a day [3]. In a 12-week pilot, NR doubled blood NAD but did not improve cognitive function, the primary outcome, or total cerebral blood flow against placebo [9].
- Population
- 20 older adults with mild cognitive impairment [3]; 42 older adults with amnestic mild cognitive impairment [9].
- Sources
- [3], [9]
- Caveats
- Two small, short pilot trials.
Blood pressure
Small trials found no drop in blood pressure against placebo in older adults, including with walking exercise.
The numbers and sources
- Effect
- In adults 55 and older with high daytime systolic pressure, 1,000 mg a day of NR with walking exercise for 6 weeks did not lower systolic pressure more than placebo with the same exercise (+5.19 against -2.71 mmHg) [10]. Blood pressure did not change in a 12-week trial in mild cognitive impairment [9].
- Population
- 54 sedentary adults, mean age 67 [10]; 42 older adults with amnestic mild cognitive impairment [9].
- Sources
- [10], [9]
- Caveats
- Pilot trials. A nighttime pressure trend in [10] came from a post hoc analysis.
Claimed, not studied in people1
Longer life
Not studied in people. Mouse studies disagree: NR lengthened lifespan in one lab, while a multi-site US aging institute program found no lifespan gain in either sex.
No study in people. This rests on animal studies.
The numbers and sources
- Effect
- In one lab, NR raised NAD, rejuvenated muscle stem cells in aged mice, delayed senescence of neural and melanocyte stem cells and increased mouse lifespan [11]. In genetically mixed mice tested at three sites by the US National Institute on Aging program, NR did not increase lifespan in males or females at the doses tested [12].
- Population
- Aged mice [11]. Genetically heterogeneous mice at three sites [12].
- Sources
- [11], [12]
- Caveats
- Mouse lifespan results do not show what happens in people. The larger multi-site test found no effect [12].
Doses studied
Trials used 100 to 1,000 mg a day for 8 weeks [2], 1 g a day for 10 weeks [3], 1,000 mg twice daily for 12 weeks [7], and 500 mg twice daily for 52 weeks [8].
Risks
Reported risks1
Worse outcomes in Parkinson disease
One trial found motor and non-motor symptoms worsened more on NR than placebo in early Parkinson disease.
The numbers and sources
- How common
- How often is not known: the sources give no rate.
- Effect
- Motor and non-motor symptom scores worsened more on NR than on placebo over 52 weeks [8]. In mild cognitive impairment, NR was linked to lower SPPB scores and slower chair-stand times [5].
- Population
- 393 people with early Parkinson disease in the primary analysis [8]; adults with mild cognitive impairment in pooled trials [5].
- Sources
- [8], [5]
- Caveats
- One trial in Parkinson disease. The findings may not apply to people without these conditions.
Checked, no increase found1
Adverse effects in trials
Side effects were about as common on NR as on placebo at 100 to 2,000 mg a day, with no flushing reported.
The numbers and sources
- How common
- How often is not known: the sources give no rate.
- Effect
- Adverse events did not differ between NR and placebo, or between doses of 100 to 1,000 mg a day, and no flushing was reported. NR did not raise LDL cholesterol [2]. At 2,000 mg a day for 12 weeks, no serious adverse events were attributed to NR and safety blood tests were normal [7]. In the 52-week Parkinson trial, serious adverse events occurred in 8.3% on NR and 14.1% on placebo [8]. Adverse event reports did not differ between groups in mild cognitive impairment [3].
- Population
- Trial participants at 100 to 2,000 mg a day for 8 to 52 weeks [2][3][7][8].
- Sources
- [2], [7], [8], [3]
- Caveats
- Most trials were small and 12 weeks or shorter. The dose-ranging safety trial was ChromaDex-funded [2].
Possible, not studied in people1
Long-term use
Not studied in people. In rats, 90 days at high doses affected the liver, kidneys, ovaries and testes. In a mouse breast cancer model, NR increased spread to the brain.
No study in people. This rests on animal studies, lab studies.
The numbers and sources
- How common
- How often is not known: the sources give no rate.
- Effect
- NR was not genotoxic in lab tests. In a 90-day rat study, NR at the highest dose had a toxicity profile similar to nicotinamide, with the liver, kidneys, ovaries and testes as target organs. The no observed adverse effect level was 300 mg/kg a day and the lowest observed adverse effect level 1,000 mg/kg a day [13]. In a mouse model of triple negative breast cancer, NR supplementation significantly increased cancer prevalence and metastases to the brain [14]. The longest human trial located ran 52 weeks [8].
- Population
- Rats, and bacterial and cell assays [13]. Mice with triple negative breast cancer [14].
- Sources
- [13], [14], [8]
- Caveats
- The rat study tested 300 to 3,000 mg/kg a day [13]. The cancer finding comes from one model of one cancer type. No human study followed use for longer than a year.
Claims tested and not found
- That NR improves insulin sensitivity. A 12-week clamp trial in obese, insulin-resistant men found no improvement [7].
- That NR slows Parkinson disease. A 52-week phase 3 trial found symptom scores worsened more on NR than placebo [8].
- That NR improves memory. Cognition scores did not change in 10-week and 12-week trials in mild cognitive impairment [3][9].
- That NR preserves muscle in older adults. A meta-analysis of randomized trials found no support for preserving muscle mass or function [5].
- That NR lowers blood pressure. Added to exercise, NR did not lower daytime systolic pressure more than placebo [10].
Sources
- Martens CR, Denman BA, Mazzo MR, et al. Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD+ in healthy middle-aged and older adults. Nature Communications. 2018. https://doi.org/10.1038/s41467-018-03421-7
- Conze D, Brenner C, Kruger CL. Safety and Metabolism of Long-term Administration of NIAGEN (Nicotinamide Riboside Chloride) in a Randomized, Double-Blind, Placebo-controlled Clinical Trial of Healthy Overweight Adults. Scientific Reports. 2019. https://doi.org/10.1038/s41598-019-46120-z
- Orr ME, Kotkowski E, Ramirez P, et al. A randomized placebo-controlled trial of nicotinamide riboside in older adults with mild cognitive impairment. GeroScience. 2023. https://doi.org/10.1007/s11357-023-00999-9
- Gallagher C, Emmanuel OO. NAD⁺ supplementation for anti-aging and wellness: A PRISMA-guided systematic review of preclinical and clinical evidence. Ageing Research Reviews. 2026. https://doi.org/10.1016/j.arr.2026.103057
- Prokopidis K, Moriarty F, Bahat G, et al. The Effect of Nicotinamide Mononucleotide and Riboside on Skeletal Muscle Mass and Function: A Systematic Review and Meta-Analysis. Journal of Cachexia, Sarcopenia and Muscle. 2025. https://doi.org/10.1002/jcsm.13799
- McDermott MM, Martens CR, Domanchuk KJ, et al. Nicotinamide riboside for peripheral artery disease: the NICE randomized clinical trial. Nature Communications. 2024. https://doi.org/10.1038/s41467-024-49092-5
- Dollerup OL, Christensen B, Svart M, et al. A randomized placebo-controlled clinical trial of nicotinamide riboside in obese men: safety, insulin-sensitivity, and lipid-mobilizing effects. The American Journal of Clinical Nutrition. 2018. https://doi.org/10.1093/ajcn/nqy132
- Brakedal B, Skeie GO, Derad C, et al. Nicotinamide Riboside for Patients With Early-Stage Parkinson Disease: The NOPARK Randomized Clinical Trial. JAMA. 2026. https://doi.org/10.1001/jama.2026.18828
- Martens CR, Decker KP, DeConne TM, et al. A phase-II randomized controlled pilot study of nicotinamide riboside supplementation in older adults with amnestic mild cognitive impairment. Alzheimer's & Dementia. 2026. https://doi.org/10.1002/alz.71605
- Lin Y, Zeidan RS, Lapierre-Nguyen S, et al. Nicotinamide riboside combined with exercise to treat hypertension in middle-aged and older adults: a pilot randomized clinical trial. GeroScience. 2025. https://doi.org/10.1007/s11357-025-01815-2
- Zhang H, Ryu D, Wu Y, et al. NAD⁺ repletion improves mitochondrial and stem cell function and enhances life span in mice. Science. 2016. https://doi.org/10.1126/science.aaf2693
- Harrison DE, Strong R, Reifsnyder P, et al. 17-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. Aging Cell. 2021. https://doi.org/10.1111/acel.13328
- Conze DB, Crespo-Barreto J, Kruger CL. Safety assessment of nicotinamide riboside, a form of vitamin B3. Human & Experimental Toxicology. 2016. https://doi.org/10.1177/0960327115626254
- Maric T, Bazhin A, Khodakivskyi P, et al. A bioluminescent-based probe for in vivo non-invasive monitoring of nicotinamide riboside uptake reveals a link between metastasis and NAD+ metabolism. Biosensors and Bioelectronics. 2023. https://doi.org/10.1016/j.bios.2022.114826