Nicotinamide Riboside (NR)
What it is
NAD+ precursor intended to restore age-related decline in cellular NAD+.
What the evidence says
Human RCTs consistently confirm NR is safe and raises blood NAD+ (often 40-90%, up to ~2.6-3x at high doses). The problem is downstream benefit: trials repeatedly fail to translate NAD+ elevation into clinical gains. A 24-week long-COVID RCT at 2000 mg/day tripled NAD+ but did not improve cognition, fatigue, sleep, or mood versus placebo, and a meta-analysis found minimal benefit for muscle in older adults. Evidence for actual longevity or function endpoints is weak.
250-1000 mg/day (up to 2000 mg/day studied); reliably raises NAD+
Educational summary of doses studied — not a recommendation. Talk to a clinician before starting any supplement.
Sources (2)
- Effects of nicotinamide riboside on NAD+ levels, cognition, and symptom recovery in long-COVID: a randomized controlled trial — eClinicalMedicine (Lancet) (PMID: 41357333) (2025)
- Repeat dose NRPT (nicotinamide riboside and pterostilbene) increases NAD+ levels in humans safely and sustainably — npj Aging and Mechanisms of Disease (PMID: 29184669) (2017)
Educational summary of published research, checked against primary sources and linked inline. Not medical advice; supplements are not FDA-evaluated to treat disease. See our editorial policy.