# NAD+ Dosage in the Research: Doses Used in Precursor and IV Studies > NAD+ dosage as reported in the literature: the NMN and NR doses used in human trials, the IV NAD+ infusion protocols, routes studied, and stability notes. Research context only, no instructions. What was administered, to whom, by which route, and for how long — reported as study parameters, not as instructions to take anything. ## The short version This page reports the doses that showed up in published NAD+ studies — nothing more. It is a research digest and gives no dosing instructions. NAD+ itself is barely absorbed when swallowed, so the human trials used precursors (building blocks the body converts into NAD+): NMN at 250-900 mg/day and NR at 250-3000 mg/day are the ranges that appear in the cited work [3][4]. IV NAD+ infusions, used in wellness clinics, ran roughly 250-1000 mg per session over hours. Below, each dose is tied to the study that used it and the species it was used in. ## Doses used in NAD+ precursor studies The figures below are study parameters from the cited trials, reported as research context. They are not recommendations, and this digest gives no human dosing instructions. - **NMN (precursor), oral:** 250 mg/day for 10 weeks raised muscle insulin sensitivity in prediabetic women [1]; 300/600/900 mg/day for 60 days raised blood NAD+ across all groups, with 600 mg/day identified as optimal in a multicenter RCT [3]; single doses of 100/250/500 mg were safely absorbed in healthy men [8]. The most-replicated NMN dose is 250 mg/day [1]. - **NR (nicotinamide riboside, precursor), oral:** 100/300/1000 mg/day for 8 weeks raised whole-blood NAD+ by 22%/51%/142% [4]; 1000 mg/day for 6 weeks raised blood NAD+ about 60% [7]; single doses of 100-1000 mg raised NAD+ dose-dependently, a 1000 mg dose by roughly 2.7-fold over 24 hours [6]. Up to 3000 mg/day has been tested for safety in other populations. - **IV NAD+ (wellness/clinical):** reported infusion protocols of roughly 250-1000 mg per session over several hours; one pharmacokinetic study used a continuous infusion of 3 micromoles per minute over 6 hours [11]. - **Nicotinamide (NAM):** 500 mg twice daily has been studied in other contexts. These are doses that produced the measured effects in the cited studies, in the species and populations noted. They describe the literature, not a protocol for any person. ## Routes studied Most controlled human NAD+ evidence is oral, using capsules or powder of NMN, NR, or nicotinamide [4][3]. The intravenous route — NAD+ infusion in wellness clinics — has limited controlled data, mostly pilot and retrospective [11]. Subcutaneous and intramuscular NAD+ injection are compounded, with minimal peer-reviewed pharmacokinetic data. Sublingual, intranasal, topical, and transdermal-patch products are marketed but have little controlled evidence behind them. The route matters because it determines what reaches the NAD+ pool. Oral precursors are absorbed and converted; intact IV NAD+ is cleared from plasma quickly [11]. The [IV NAD+ research](/iv-nad) covers the infusion pharmacokinetics in detail. ## How long does infused or supplemented NAD+ persist? NAD+ itself is not freely taken up intact by most cells, and infused IV NAD+ is rapidly cleared from plasma — a pilot study found near-complete plasma removal within about the first two hours of infusion [11]. Oral precursors behave differently: they are absorbed and raise whole-blood NAD+ over days to weeks, with the elevation persisting through chronic dosing in 8-12 week trials [4][7]. So 'how long it lasts' depends entirely on the form — minutes-to-hours of plasma persistence for intact infused NAD+, versus a sustained blood-NAD+ rise maintained across weeks of oral precursor dosing [4]. ## Stability and product-quality notes 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 contamination and endotoxin risk — an FDA Class I recall has been issued for a compounded NAD+ injection over elevated endotoxin. Supplement-grade products also vary widely in purity and actual content, and third-party testing is not guaranteed. These are documented quality concerns in the record, not a critique of any specific named product. --- A specimen sheet of the NAD+ record — every precursor effect-size stamped to its study and every gap stamped just as plainly; no clinic behind the concrete and nothing here dispensed, priced, or sold.