Nicotinamide riboside (NR)
Summary
Nicotinamide riboside raised blood NAD+ in several placebo-controlled trials at 100–2,000 mg/day and was well tolerated in trials of up to 12 weeks. Trials found no improvement in insulin sensitivity or most metabolic markers. One 6-month trial in people with leg artery disease found longer walking distance. Muscle-function evidence in older adults is not supportive.
Key facts
- Nicotinamide riboside chloride; a crystal form (NIAGEN) was used in the 8-week dose trial and is the subject of FDA GRAS notice 635[1][2]
- No head-to-head human data between NR products in our sources[2]
- Blood NAD+ ↑ (C); insulin sensitivity and glucose metabolism: no improvement (C); six-minute walk ↑ in leg artery disease (C); body composition: minor change in one small trial (D)[4][3][5][6]
- No flushing and no difference in adverse events versus placebo at 100–1,000 mg/day for 8 weeks; 2,000 mg/day for 12 weeks appeared safe in 40 men[2][3]
- FDA had no questions about a GRAS notice for nicotinamide riboside chloride as a vitamin B3 source in foods (closed August 3, 2016)[1]
- 4 graded human outcomes on this page
- October 9, 2026
How it works
ProposedNR is converted to NAD+, a cofactor central to energy metabolism. Oral NR raised blood NAD+ and NAD+ metabolites in human trials (established). Effects on metabolism, inflammation and brain function come mainly from rodent studies and remain proposed for people.[2][4][9]
What the human research says
Human trials only, one row per outcome. The form column shows what each trial actually tested. Grades follow our evidence-grading policy.
At a glance: strongest evidence per outcome
| Outcome | Grade | Effect | Strongest evidence | Rows |
|---|---|---|---|---|
| Healthy aging | Grade C | Improved | RCT · n = 90 · 2024 | 2 rows |
| Metabolic | Grade C | No effect | RCT · n = 40 · 2018 | 2 rows |
Every graded row
| Outcome | Effect | Grade | Best evidence | PMID |
|---|---|---|---|---|
| Six-minute walking distance | Improved | Grade C | RCT · n = 90 · 2024 People with lower-extremity peripheral artery disease Form: Nicotinamide riboside, with or without resveratrol, vs placebo · Dose: Not stated in the abstract · Duration: 6 months NR improved six-minute walk versus placebo (+7.0 vs -10.6 meters; difference +17.6 m). Adding resveratrol did not add benefit. | 38871717 (opens PubMed)Source [5] |
| Insulin sensitivity and glucose metabolism | No effect | Grade C | RCT · n = 40 · 2018 Sedentary men aged 40–70 with obesity (BMI > 30) and insulin resistance Form: Nicotinamide riboside vs placebo · Dose: 1,000 mg twice daily (2,000 mg/day) · Duration: 12 weeks NR did not improve insulin sensitivity, glucose production, glucose disposal, energy expenditure, fat oxidation or body composition. No serious adverse events were observed. | 29992272 (opens PubMed)Source [3] |
| Blood NAD+ levels | Improved | Grade C | RCT · n = 20 · 2024 Older adults with mild cognitive impairment Form: Nicotinamide riboside vs placebo · Dose: Escalated to 1 g/day · Duration: 10 weeks Blood NAD+ rose 2.6-fold with NR, with no between-group difference in adverse events. Cognition scores (MoCA) did not change. | 37994989 (opens PubMed)Source [4] |
| Fat-free mass and sleeping metabolic rate | Improved | Grade D | Crossover RCT · n = 13 · 2020 Healthy men and women with overweight or obesity Form: Nicotinamide riboside vs placebo · Dose: 1,000 mg/day · Duration: 6 weeks per phase Fat-free mass was slightly higher after NR (change 1.34%) and sleeping metabolic rate rose. No effects were found on insulin sensitivity, mitochondrial function, liver fat, blood pressure or inflammation markers. | 32320006 (opens PubMed)Source [6] |
Forms
| Form | Elemental % | Absorption (human data) | GI tolerance | Studied for |
|---|---|---|---|---|
| Nicotinamide riboside chloride (capsules, powder) | Varies[1] | 100, 300 and 1,000 mg/day raised whole-blood NAD+ dose-dependently within 2 weeks; oral NR reached aged muscle in a 21-day crossover trial.[2][9] | No flushing and no difference in adverse events versus placebo over 8 weeks.[2] | NAD+ levels, metabolic health, walking performance, cognition |
Studied doses
Doses studied in human trials ranged from 100 to 2,000 mg of nicotinamide riboside a day for 21 days to 6 months.[2][3][9][5]
Interactions
Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.
None found in our sources.
Who should be careful
- Long-term use
- The trials we reviewed ran for 6 months at most, and safety was reported for up to 12 weeks, so longer-term safety is not established.[5][3]
- Older adults seeking muscle benefits
- A 2025 meta-analysis concluded that current evidence does not support NR or NMN for preserving muscle mass and function in adults over 60.[7]
- Before you start
- Talk to your pharmacist or clinician before adding this supplement, especially if you take prescription medicines, are pregnant or breastfeeding, or have a chronic health condition.[2]
Talk to your pharmacist or clinician before starting a supplement, especially if you take prescription medicines.
Articles about Nicotinamide riboside (NR)
Plain-English answers to common questions, built on the evidence above.
Frequently asked questions
Does nicotinamide riboside raise NAD+?
Yes. In an 8-week trial, 100, 300 and 1,000 mg/day raised whole-blood NAD+ by 22%, 51% and 142%, and a 10-week pilot found a 2.6-fold rise at 1 g/day. A 2 x 6-week crossover trial in healthy middle-aged and older adults also found NR stimulated NAD+ metabolism.[2][4][10]
Does NR improve blood sugar or metabolism?
Not in the trials so far. A 12-week trial of 2,000 mg/day in 40 men with insulin resistance found no change in insulin sensitivity or body composition, and a 6-week crossover trial found no effect on insulin sensitivity. A 2022 meta-analysis of NAD+ precursors found no significant effect of NR on blood lipids, though few NR studies were available.[3][6][8]
Does NR cause flushing like niacin?
In an 8-week trial of 100–1,000 mg/day there were no reports of flushing and no difference in adverse events versus placebo.[2]
Does NR help muscle strength in older adults?
A 2025 meta-analysis of NR and NMN trials in adults with a mean age over 60 concluded the evidence does not support them for preserving muscle mass and function.[7]
How is NR different from NMN?
Both are NAD+ precursors. Our sources contain no head-to-head human trial comparing them.[7]
Is NR allowed in foods and supplements in the US?
FDA had no questions about a 2016 GRAS notice for nicotinamide riboside chloride as a vitamin B3 source in foods such as drinks and bars. The ingredient was also the subject of two new dietary ingredient notifications for supplements, according to an 8-week trial report.[1][2]
Sources
- [1]GRN No. 635: Nicotinamide riboside chloride (FDA has no questions, closed Aug 3, 2016). U.S. Food and Drug Administration, 2016. database
- [2]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.. Sci Rep, 2019. RCT
- [3]A randomized placebo-controlled clinical trial of nicotinamide riboside in obese men: safety, insulin-sensitivity, and lipid-mobilizing effects.. Am J Clin Nutr, 2018. RCT
- [4]A randomized placebo-controlled trial of nicotinamide riboside in older adults with mild cognitive impairment.. Geroscience, 2024. RCT
- [5]Nicotinamide riboside for peripheral artery disease: the NICE randomized clinical trial.. Nat Commun, 2024. RCT
- [6]Nicotinamide riboside supplementation alters body composition and skeletal muscle acetylcarnitine concentrations in healthy obese humans.. Am J Clin Nutr, 2020. crossover-RCT
- [7]The Effect of Nicotinamide Mononucleotide and Riboside on Skeletal Muscle Mass and Function: A Systematic Review and Meta-Analysis.. J Cachexia Sarcopenia Muscle, 2025. meta-analysis
- [8]Effects of NAD+ precursor supplementation on glucose and lipid metabolism in humans: a meta-analysis.. Nutr Metab (Lond), 2022. meta-analysis
- [9]Nicotinamide Riboside Augments the Aged Human Skeletal Muscle NAD+ Metabolome and Induces Transcriptomic and Anti-inflammatory Signatures.. Cell Rep, 2019. crossover-RCT
- [10]Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD+ in healthy middle-aged and older adults.. Nat Commun, 2018. crossover-RCT
What changed
- First draft. Every evidence-row PMID checked with NCBI E-utilities (esummary + efetch abstract) and re-read in an independent adversarial pass.