# NAD+ Dosage in the Research: Precursor Doses Used in Human Trials

> NAD+ dosage as studied, not recommended: oral NMN 250-900 mg/day, NR 250-1000 mg/day (up to 3000 mg/day tested for safety), and the IV NAD+ infusion protocols reported in the literature.

These are the doses studies administered, by route, with the blood-NAD+ readouts they produced. They are a record of the literature, not a recommendation to take anything.

## Read this first

Everything below describes doses used in published research — what was given, to whom, by which route, for how long. It is not advice, and there are no instructions here for taking any product. Because oral **NAD+** itself is poorly absorbed intact, the doses that matter are precursor doses: oral NMN and NR, plus the slow IV NAD+ infusions reported in wellness settings. The most-replicated single figure to anchor on is NMN 250 mg/day, the dose used in the muscle-insulin-sensitivity trial [1]. Higher doses have been tested mainly to map the dose-response and to check safety, not because more is established as better.

## Doses Used in NAD+ Precursor Studies

**Oral NMN (precursor):** human randomized trials have used 250-900 mg/day, with 250 mg/day the most-replicated dose and doses up to 1200 mg/day studied [1][3]. The 10-week muscle-insulin-sensitivity trial used 250 mg/day [1]; the multicenter dose-response trial compared 300, 600, and 900 mg/day over 60 days and named 600 mg/day optimal [3].

**Oral nicotinamide riboside (NR, precursor):** commonly 250-1000 mg/day, with the benchmark dose-finding trial using 100, 300, and 1000 mg/day for eight weeks [4]. Up to 3000 mg/day has been tested for safety (the NR-SAFE design in Parkinson's disease), and the 2026 crossover used 1200 mg/day [13].

**IV NAD+ (wellness/clinical):** reported infusion protocols run roughly 250-1000 mg per session over several hours; one pharmacokinetic study used a 3 µmol/min continuous infusion over six hours [10]. Infusions are run slowly because faster rates provoke chest and abdominal discomfort [10].

**Nicotinamide (NAM):** 500 mg twice daily has been studied for skin-cancer chemoprevention [10].

## Routes studied, and how they differ

The bulk of controlled human evidence comes from the oral route — capsules and powders of NMN, NR, or nicotinamide — which raises whole-blood NAD+ reliably and dose-dependently [4]. Intravenous NAD+ infusion, used in wellness clinics, has only limited and mostly pilot or retrospective data [10]. Subcutaneous and intramuscular NAD+ injection is compounded and has minimal peer-reviewed pharmacokinetic data [10]. Sublingual, intranasal, and topical or transdermal patch products are marketed but have little controlled evidence behind them [10]. The preclinical literature underscores that route and duration interact: in cognitive-disease rodent models, repeated parenteral dosing over 7-28 days worked while a single large subcutaneous NMN injection did not [15]. There is no head-to-head route comparison in humans.

## Why there is no single 'NAD+ dose'

Two reasons a clean number does not exist. First, the molecule actually dosed is usually a precursor, and NMN and NR are not interchangeable milligram-for-milligram — the 2026 crossover showed NR producing a 2.3-fold larger blood-NAD+ rise than NMN at equal dose [13]. Second, the meaningful pharmacodynamic endpoint is a sustained shift in the blood NAD+ pool over weeks, not a single-dose blood level, since the precursors raise NAD+ progressively and the elevation holds through chronic dosing [4][3]. Stability is a practical footnote: NAD+ and NMN are hygroscopic and degrade with heat and moisture, and reconstituted injectable NAD+ should be kept cold and protected from light [10]. For the trial-by-trial outcomes behind these doses, see [recent NAD+ research](/research).

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A billboard reading of the NAD+ record — the precursor trials that reliably raise blood NAD+ set in large type, the rapidly-cleared IV claims and the still-preliminary human endpoints qualified in the line beneath, the FDA injectable recall and the NMN-supplement dispute flagged in plain sight; no clinic behind the broadcast and nothing here infused, dosed, prescribed, or sold.