Nicotinamide Riboside (NR)
An NAD+ precursor that reliably raises NAD+ but has yet to prove durable clinical benefits.
What is Nicotinamide Riboside (NR)?
Nicotinamide Riboside (NR) is a longevity supplement used for reliably and dose-dependently raises whole-blood nad+ levels in humans, confirming target engagement. NutriDex grades the human evidence as Preliminary. Nicotinamide riboside (NR) is a form of vitamin B3 that the body converts into nicotinamide adenine dinucleotide (NAD+), a coenzyme central to energy metabolism and cellular repair that declines with age. Multiple randomized controlled trials confirm that oral NR reliably and dose-dependently raises blood NAD+ levels and is well tolerated, establishing clear biological target engagement. However, this NAD+ boost has not yet translated into robust clinical benefits: trials in obese, insulin-resistant men showed no improvement in insulin sensitivity, and a trial in peripheral artery disease found no improvement in walking performance. The most promising—but still preliminary—human signal is a modest reduction in systolic blood pressure and improved endothelial function in midlife and older adults with elevated blood pressure. Overall, NR is a credible NAD+ precursor whose marketed anti-aging, metabolic, and cardiovascular benefits remain largely unproven in humans and require larger, longer trials.
Purported Benefits
Evidence by outcome
The same supplement can be well-proven for one use and unproven for another — here is the human evidence graded outcome by outcome.
| Outcome | Evidence | Effect | Studies |
|---|---|---|---|
| Raises whole-blood NAD+ levelsMultiple RCTs show reliable dose-dependent NAD+ rise (up to several-fold); clear target engagement. | Strong | ↑ benefit · large | 4 |
| Safety / tolerabilityWell tolerated up to 3000 mg/day across trials including Parkinson's and HFrEF, only mild adverse effects. | Strong | ↑ benefit · large | 4 |
| Systolic BP / endothelial function (elevated-BP adults)Pooled and crossover RCTs suggest ~8-9 mmHg SBP drop in those with high baseline BP; needs larger confirmation. | Preliminary | ↑ benefit · moderate | 2 |
| Insulin sensitivity / glucose metabolismRCT in obese men found no improvement; NAD-precursor MA even showed slightly raised fasting glucose. | Moderate | — no effect · negligible | 2 |
| Walking performance in peripheral artery diseaseNICE trial primary endpoint non-significant overall; a modest 6-min-walk gain emerged only in adherent participants. | Mixed | ↔ mixed · small | 2 |
| Muscle mass / strength / gait in older adultsTwo 2025 MAs found no improvement in muscle index, grip strength, gait speed, or chair-stand. | Moderate | — no effect · negligible | 2 |