DOSAGE DESK / STUDY PARAMETERS
NAD+ dosage: the doses studied in the research literature
What precursors were given, at what doses, by what route, for how long — read as trial parameters from the published record, never as a dosing instruction.
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This page catalogues the NAD+ dosage figures that appear in published studies — the amounts of precursor (NMN and NR, the building blocks the body turns into NAD+) that researchers actually gave participants. These are study parameters: the doses a trial used, reported so a reader can interpret the results below. They are not a recommendation, and this digest gives no instructions for human use. Plain NAD+ swallowed as a pill is poorly absorbed, so nearly all of these doses are precursors, and the injectable route is filed separately under its caveats.
Doses studied in the research literature
Across the human trials, the NAD+ dosage figures cluster by precursor. Oral NMN was studied at 250–900 mg/day, with 250 mg/day the most-replicated dose [1][6][7] and 300–900 mg/day used in the multicenter dose-ranging trial that named 600 mg/day optimal [3]. Oral NR was studied at 100–1000 mg/day in its core dose-response trial [4], with the broader literature running 250–1000 mg/day commonly and up to 2,000 mg/day for 20 weeks tested for safety with no serious adverse events [8]. Nicotinamide (NAM), the older vitamin-B3 form, has been studied at 500 mg twice daily in a separate skin-cancer chemoprevention context.
For the compounded routes, reported IV NAD+ protocols run roughly 250–1000 mg per session over several hours, and a pharmacokinetic study used a continuous infusion across six hours — figures recorded here strictly as what protocols have used, not as endorsed practice. Again: these are study parameters. No dose on this page is offered as guidance for human use.
Routes studied, and why the route changes everything
The route is not a detail — it is the variable that most determines whether NAD+ rises and for how long. Oral capsules and powders of NMN, NR, and nicotinamide carry the bulk of the controlled human evidence and reliably raise blood NAD+ over days to weeks [4][6]. Intravenous NAD+ infusion, used in wellness clinics, has limited controlled data — mostly pilot or retrospective — and the infused coenzyme is rapidly cleared from plasma. Subcutaneous and intramuscular NAD+ injections are compounded with minimal peer-reviewed pharmacokinetic data, and sublingual, intranasal, topical, and transdermal patches are marketed with little controlled evidence. The further a route gets from oral precursors, the thinner the data.
Stability shapes handling too: NAD+ and NMN are hygroscopic and degrade with heat and moisture, and reconstituted injectable NAD+ must be kept cold and protected from light. Compounded injectables carry a contamination risk — an FDA Class I recall has been issued for a compounded NAD+ injection over elevated endotoxin [8].
Tolerability and reported adverse effects in trials
On NAD+ side effects, the oral precursor trials read reassuringly within their own scope. NR produced no flushing at 100–1000 mg/day and showed no significant adverse-event difference from placebo, without elevating LDL cholesterol [4]. NMN trials at 250–900 mg/day reported no safety issues and no serious adverse events across 60 days to 24 weeks [3][6][8]. The 2023 review confirmed safety across compounds and doses, with NR tested to 2,000 mg/day for 20 weeks [8].
The injectable route is where the discomfort sits: IV NAD+ run too fast can cause flushing, nausea, and chest or abdominal pressure, transient effects tied to infusion rate [14]. The documented hard risk is contamination, not pharmacology — the FDA Class I endotoxin recall of a compounded NAD+ injection [8]. A theoretical concern also runs through the cancer literature: because NAD+ supports proliferating cells, its role in oncology is dual and context-dependent, so caution is advised in cancer populations [14][12].
How much NAD should I take?
This digest gives no human dosing instruction. The research doses studied include NMN 250–900 mg/day and NR 250–1000 mg/day, with NR tested up to 2,000 mg/day for safety [4][8]. Those figures are reported as study parameters — what trials administered — not as guidance. The decision to use any supplement belongs with a qualified clinician, not a reading of the literature.