NAD+ dosage as it appears in the research literature

Before the details

This page reports the doses scientists used in published studies. It is not a recommendation, and it contains no instructions for taking anything. A key fact frames everything below: the NAD+ molecule itself is poorly absorbed by mouth, so trials almost always give a precursor — NMN or NR, the building blocks the body converts into NAD+. "NAD+ dosage" in human research therefore usually means a precursor dose. Numbers here describe what was administered to study participants, by which route, for how long, and what was measured — nothing more.

Doses Used in the Research Literature

In human randomized trials, NMN clustered at 250–900 mg/day taken orally, with 250 mg/day the most-replicated dose and up to 1200 mg/day studied ^[1][3][6]. Nicotinamide riboside (NR) was commonly tested at 250–1000 mg/day orally, and up to 3000 mg/day in a safety study (NR-SAFE) in Parkinson's disease research ^[4]. Plain nicotinamide (NAM) at 500 mg twice daily has been studied for skin-cancer chemoprevention, a separate use from NAD+-boosting.

The dose–response is the cleanest part of the record. NR at 100/300/1000 mg/day raised whole-blood NAD+ by 22%/51%/142% ^[4]; NMN at 300/600/900 mg/day raised blood NAD+ across all groups, with 600 mg/day identified as optimal ^[3]. The functional-endpoint trials used doses at the lower end of that range: 250 mg/day produced the muscle insulin-sensitivity gain in prediabetic women ^[1] and the aerobic-capacity gain in runners ^[7], and a 100–500 mg/day NMN study in older adults showed dose-dependent NAD+ elevation with the clearest functional benefit at 250–500 mg/day ^[6].

A recurring caveat sits underneath every dose figure: supplement-grade products vary widely in purity and actual content, and third-party testing is not guaranteed ^[12]. A labeled milligram amount on a product is not the same as a verified delivered dose. These are doses studied in trials, reported here as research findings. This digest gives no human dosing instructions.

Routes of Administration

The bulk of controlled human evidence comes from the oral route — capsules and powders of NMN, NR or nicotinamide ^[4][3][1]. Intravenous NAD+ infusion is used in wellness clinics but rests on limited controlled data, mostly pilot or retrospective ^[12]. Subcutaneous and intramuscular NAD+ injection is compounded, with minimal peer-reviewed pharmacokinetic data. Sublingual, intranasal, topical and transdermal-patch formats are marketed but have little controlled evidence behind them.

The route hierarchy is essentially an evidence hierarchy. Oral precursors sit at the top because that is where the randomized, placebo-controlled trials were run ^[4][3][1]; IV NAD+ sits near the bottom on controlled efficacy data despite its marketing visibility ^[12]; and the consumer formats — patches, sprays, lozenges — sit lower still, with the blood-NAD+ elevation evidence resting almost entirely on oral capsules and powders ^[4][3].

NAD+ and NMN are hygroscopic and degrade with heat and moisture; reconstituted injectable NAD+ should be kept cold and protected from light. Compounded injectables carry a contamination risk — the FDA has issued a Class I recall of a compounded NAD+ injection over elevated bacterial endotoxin. The route page covers this in detail under IV NAD+ therapy research.

How Long NAD+ and Its Precursors Persist

NAD+ itself is not freely taken up intact by most cells. Infused intravenous NAD+ is rapidly cleared from plasma — a pilot study found near-complete plasma removal within roughly the first two hours of infusion ^[12]. This is the pharmacokinetic core of why IV "NAD+" and oral "NAD+" behave so differently.

Oral precursors work on a slower timescale. Absorbed NMN and NR raise whole-blood NAD+ over days to weeks, and that elevation persists through chronic dosing across 8–12 week trials ^[4][3]. So the relevant "half-life" question has two answers: infused NAD+ disappears from blood within hours ^[12], while the NAD+ elevation produced by oral precursors is a steady-state effect maintained by repeated dosing ^[4].

What Actually Reaches the Blood

The reason trials report whole-blood NAD+ rather than tissue NAD+ is practical: sampling tissue NAD+ in living people is invasive and rare, so blood is the standard pharmacodynamic readout ^[12]. That readout responds cleanly to oral precursors. NR produced a 22%/51%/142% rise at 100/300/1000 mg/day ^[4], and NMN produced a significant rise at every dose from 300 to 900 mg/day, sustained at days 30 and 60 ^[3]. The signal is dose-dependent and durable across the dosing period.

What blood NAD+ does not tell you is how much each tissue gains, and the 2025 Nature Metabolism review flags exactly this gap — tissue-specific NAD+ data in humans remain sparse ^[12]. So the honest reading of the dose literature is that precursors reliably raise the circulating biomarker ^[4][3], while the downstream tissue distribution, and whether it matters clinically, is less settled ^[12]. The doses above are reported as what was studied, not as guidance.

Non-Pharmacological Inputs

Dose is not the only lever on NAD+. Exercise raises NAMPT, the rate-limiting salvage enzyme. Aerobic and resistance training increased NAMPT protein in human skeletal-muscle biopsies by roughly 12–30%, with proportionally larger gains in older adults ^[9]. NAMPT expression also follows a circadian rhythm under the CLOCK-SIRT1-NAMPT feedback loop, which is why NAD+ levels in tissues oscillate across the day ^[5]. The research describes exercise as a non-pharmacological way to maintain NAD+ salvage capacity, sometimes proposed alongside precursor approaches rather than as a substitute for them ^[9].

The circadian point also bears on a common timing question. Because NAMPT, and therefore NAD+ synthesis, rises and falls on a daily clock, it is biologically plausible that dose timing could matter ^[5] — but no human trial has compared morning versus night dosing, so the literature offers a mechanism without a verdict.