NR (Nicotinamide Riboside)
Also known as: Nicotinamide Riboside, Niagen, NR Chloride
Lower numbers = closer to natural. Higher numbers = more enhanced.
Why this rating?
NR is an oral NAD+ precursor (a form of vitamin B3) taken to raise cellular NAD+ for longevity and cellular-energy goals. It is not a hormone or anabolic, no effect on testosterone, IGF-1, or muscle mass. Among the NAD+ precursors it has the strongest published human safety/pharmacokinetic dataset, but demonstrated clinical benefits in healthy people remain modest. Rated 1 as a cellular-health/longevity supplement with no performance-enhancing effect.
Overview
A form of vitamin B3 and one of the two leading oral NAD+ precursors (alongside NMN). NR has the deepest human dataset of any NAD+ precursor. Multiple RCTs confirm it raises blood NAD+ safely and without the flushing of high-dose niacin. It is the precursor to reach for when you want the best-characterised human evidence. See the NAD+ page for the shared biology.
Purpose & Use Cases
NAD+ Restoration
Robustly and repeatedly shown in human RCTs to raise blood NAD+, the best-replicated pharmacodynamic effect among NAD+ precursors.
Longevity / Sirtuin Support
Supplies NAD+ substrate for sirtuins and one-carbon/energy metabolism. Often paired with resveratrol (activator) on a "fuel + activator" rationale.
Metabolic / Cellular Health
Studied in aging, cardiometabolic, and neurological contexts (e.g. the NADPARK trial in Parkinson's). NAD+ elevation is consistent; hard clinical outcomes in healthy people are still modest and mixed.
Benefits
- Best-characterised human evidence among NAD+ precursors
- Reliably raises blood NAD+ without flushing
- Excellent safety/tolerability record in RCTs
- Regulatorily clearer than NMN in the USA
- Non-hormonal: no HPTA effect, no PCT
Good to Know
The NAD+ precursor with the best human data
Nicotinamide riboside has the strongest clinical evidence for actually raising blood NAD+ in humans, without flushing. It enters cells via the NRK pathway.
No methylation problem at normal doses
A controlled trial of 1g/day NR for 30 days showed no change in homocysteine or methylation markers, even in people with MTHFR variants. So the "you must add TMG" advice is precautionary rather than proven for NR.
NR vs NMN
NR and NMN both funnel into the same NAD salvage pathway. NR has more published human data; NMN is one step closer to NAD+. In practice their effects are similar, and neither flushes like niacin.
Dosage Guidelines
| Experience Level | Dosage Range |
|---|---|
| Beginner | 250 – 300 mg/day |
| Intermediate | 300 – 500 mg/day |
| Advanced | 500 – 1000 mg/day |
Human trials commonly use 250-1,000mg/day; 1,000mg/day has been studied for weeks to months with a clean safety profile (e.g. the 30-day NADPARK trial and the 8-week Conze et al. healthy-adult safety trial). NAD+ rises within days to ~2 weeks. A dedicated high-dose safety RCT (NR-SAFE) gave 3,000mg/day (1,500mg twice daily, no titration needed) for 4 weeks with only mild adverse events and no serious safety signal, so doses above 1g/day are tolerated, but there is little evidence they add extra clinical benefit versus the 250-1,000mg/day range most people use. Like NMN (and unlike nicotinic acid/niacin), NR does not cause flushing.
NR itself has a short parent-compound half-life; the effect is tracked by the sustained rise in blood NAD+ rather than a parent-compound half-life.
Side Effects
GI Upset
uncommonMild nausea, bloating, or discomfort, usually at higher doses.
Take with food; lower the dose.
Mild Flushing / Itch
rareUncommon and mild: NR does not act through GPR109A the way nicotinic acid does, so true niacin flushing is not expected.
Generally not a practical concern.
General Mitigation Strategies
Among the best-tolerated longevity supplements in the human literature. RCTs at doses up to 3,000mg/day (NR-SAFE) report only mild adverse events (headache, tremor, GI symptoms) with no serious safety signal versus placebo; a mild early rise in homocysteine seen at that dose stabilized and did not indicate methyl-donor depletion. Minor GI complaints resolve with food or a lower dose.
Support Supplements
Ancillary supplements commonly run alongside NR (Nicotinamide Riboside) to manage side effects, support the target tissue, or fill nutrient demands it creates.
TMG (Trimethylglycine / Betaine)
Methyl-donor "insurance." NAD turnover generates nicotinamide, which NNMT clears by methylation using SAM, spending methyl groups and producing homocysteine. TMG remethylates homocysteine back to methionine to buffer that drain.
- Dose
- 500-1,000mg/day
- Timing
- Daily, with the NR dose or a meal
- When
- Honest evidence: for NR the methyl-depletion worry is largely THEORETICAL, the Gaare et al. (NADPARK-linked) RCT gave 1,000mg/day NR for 30 days and found NO change in homocysteine, SAM/SAH, or global DNA methylation (even in carriers of MTHFR variants). A higher-dose safety RCT (NR-SAFE, 3,000mg/day) did see a mild early homocysteine rise that stabilized without depleting the methyl-donor pool. So TMG is optional insurance for NR, not a biochemical requirement. It is best-justified with high-dose nicotinic acid (niacin), which reliably raises homocysteine.
Post Cycle Therapy (PCT)
Not hormonal. No PCT required.
How It Works
NR is phosphorylated by nicotinamide riboside kinases (NRK1/2) to NMN, which is then converted to NAD+ by NMNATs, entering the salvage pathway one step "upstream" of NMN. NAD+ is a central coenzyme for energy metabolism and a substrate for sirtuins and PARPs (DNA repair, stress response). Because NR is efficiently taken up and phosphorylated, oral dosing reliably raises circulating NAD+ in humans.
Fundamentals
Reference on the practices relevant to NR (Nicotinamide Riboside): how they are done and where they go wrong. Not a recommendation to use it.
Common Stacks
- NR + TMG - NAD precursor with (optional) methyl-donor support
- NR + Resveratrol - Sirtuin fuel + activator longevity stack
Legal Status
Dietary supplement (USA); NR chloride/Niagen has FDA NDI/GRAS notifications, regulatorily clearer than NMN.
Legal status varies by country and changes over time. This is a general summary, not legal advice.
WADA Status
NR is not on the WADA Prohibited List. It is a form of vitamin B3 (an NAD+ precursor) sold as a supplement. As with any supplement, third-party-tested products are preferable for tested athletes.
References
- Gaare et al.: NR (1g/30d) does not alter methylation homeostasis, RCT (PMC10014306)
- What is really known about the effects of NR supplementation in humans (Science Advances)
- Brakedal et al.: NADPARK study, randomized phase I NR trial (Cell Metabolism)
- Berven et al.: NR-SAFE, high-dose (3g/day) NR safety RCT in Parkinson's disease (Nature Communications, PMC10684646)