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Longevity

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NAD+ precursor

Nicotinamide Riboside (NR)

Also known as: NR, Niagen, Tru Niagen, ChromaDex NR, 1-Beta-D-ribofuranosyl-3-carboxyamide-pyridinium

Oral NAD+ precursor with consistent evidence that it raises blood NAD+ in humans — but underwhelming evidence that the NAD+ rise translates to clinical outcomes outside specific populations.

Reviewed 2026-05-05

What it does

Nicotinamide riboside (NR) is one of the principal oral NAD+ precursors, sold most widely as Niagen / Tru Niagen by ChromaDex. Mechanistically it enters cells via specific transporters and is phosphorylated by nicotinamide riboside kinases (NRK1/2) to NMN and then to NAD+, bypassing the rate-limiting niacin pathway. Its inclusion in this 'peptide companion' library follows the same logic as NAD+ and NMN — community use stacks NR with peptide regimens, and most competitors lump NR in with peptides without disclosing it isn't one. NR has a substantial human-trial program, more than NMN: oral NR consistently raises blood NAD+ levels in healthy adults at 250–1000 mg/day. The harder question — whether the NAD+ rise drives clinically meaningful changes in metabolic health, cognitive function, or aging biomarkers — has produced largely null or modest results across multiple RCTs.

Used for

Dose

Starting
250,000 mcg · once daily
Common
625,000 mcg · once daily
Upper
1,000,000 mcg · once daily
When
MorningNAD precursor; same morning logic as NAD+ IV. With food when possible — improves tolerability for some users.
Site
oral

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⚠ Caution

  • Pregnancy and breastfeeding (limited safety data at supplement doses)
  • Active malignancy — NAD+ metabolism intersects with cancer biology in dose- and tumor-type-dependent ways; consult oncology
  • Caution with chemotherapy regimens whose mechanism involves NAD+/PARP signaling
  • Known hypersensitivity

Your stack

Track this peptide in your protocol — dose, schedule, vials on hand, refill projection. Stays in your browser; no account needed.

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Use this peptide

Featured in protocols
Reconstitution & storage

Oral capsule supplement — no reconstitution.

Storage. Room temperature, dry, protected from light. Niagen and similar products typically have 2-year shelf life from manufacture.

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Monitoring & questions

Reported side effects
  • Generally well tolerated at 250–1000 mg/day
  • Mild GI upset (nausea, indigestion)
  • Headache
  • Flushing (less than niacin/nicotinic acid; sometimes still reported)
  • Theoretical: long-term effects of sustained high cellular NAD+ on sirtuin activity, cancer biology, and immune signaling are not fully characterized in humans

Reference

How it works

Enters cells via equilibrative nucleoside transporters (ENT1, ENT4) and the recently characterized SLC12A8 transporter (more relevant for NMN). Phosphorylated by nicotinamide riboside kinase (NRK1 or NRK2) to nicotinamide mononucleotide (NMN), which NMNAT enzymes convert to NAD+. This salvage pathway bypasses the rate-limiting nicotinamide phosphoribosyltransferase (NAMPT) step and produces NAD+ more efficiently than niacin (nicotinic acid) without the flushing.

EvidenceTier 2 — Human observational

Tiers are per indication. The same molecule can be Tier 1 for one use and Tier 4 for another — the tier reflects published literature, not community framing.

Raising blood NAD+ levels (biomarker)

Tier 2high confidence

Multiple human RCTs (Martens 2018, Trammell 2016, Conze 2019) consistently demonstrate dose-dependent increases in whole-blood NAD+ levels with oral NR at 250–1000 mg/day. The biomarker effect is robust. Tier 2 because the indication is biochemical, not clinical-outcome.

Martens CR et al. 2018Conze D et al. 2019

Cardiovascular / vascular function (older adults)

Tier 3medium confidence

Martens 2018 reported reduced systolic blood pressure (~6 mmHg) and arterial stiffness improvements in middle-aged/older adults with elevated baseline BP. Effect size is modest; a few subsequent trials are mixed. Tier 3.

Martens CR et al. 2018

Cognitive performance / brain NAD+

Tier 3medium confidence

Some MRS imaging studies report measurable brain NAD+ increases with oral NR; clinical cognitive endpoints are mixed. Brink 2022 in Parkinson's reported some symptomatic improvements at 1000 mg/day. Underpowered for definitive conclusions.

Brink BG et al. 2022

Skeletal muscle metabolism / insulin sensitivity

Tier 3medium confidence

Multiple small RCTs in healthy and prediabetic adults show null to modest effects on insulin sensitivity. Inconsistent findings limit the indication to Tier 3.

No primary citations are anchored to this indication — the tier reflects the absence of usable literature, not a missing reference.

General anti-aging / longevity

Tier 4high confidence

Aggressive marketing positions NR as an anti-aging intervention. Evidence is mechanistic and biomarker-level; no longevity outcome trial in humans.

No primary citations are anchored to this indication — the tier reflects the absence of usable literature, not a missing reference.

Citations (3)
  1. [1]
    Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD+ in healthy middle-aged and older adults
    Martens CR, Denman BA, Mazzo MR, et al. · Nature Communications · 2018 · PMID 29467442
    Foundational human RCT — NR raises NAD+, modest BP/arterial stiffness improvement in older adults. Anchor for biomarker and CV indications.
    View source
  2. [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
    Conze D, Brenner C, Kruger CL · Scientific Reports · 2019 · PMID 31604941
    Long-term safety and pharmacokinetic data for NR in overweight adults — supports the biomarker indication and safety profile.
    View source
  3. [3]
    An exploratory study of the effect of high-dose nicotinamide riboside on motor function in patients with Parkinson disease
    Brink BG, et al. (NR-PD trial) · Nature Medicine · 2022 · PMID 35332179
    Pilot RCT of high-dose NR in Parkinson's — anchor for Tier 3 cognitive/neurologic indication.
    View source