# NAD+ Dosage in the Research: Doses, Routes and Tolerability > NAD+ dosage as studied, not prescribed: NMN 250–900 mg/day, NR 250–1000 mg/day (tested to 3000), IV protocols, plus reported side effects. Research framing only — no dosing instructions. Cited. The doses, routes and durations that trials actually used — reported as study protocols, never as a recommendation or an instruction. ## Before the details This page lists the NAD+ dosage figures that appear in published studies — what researchers gave, by which route, for how long. It is a record of the literature, not a dosing guide. Because plain NAD+ is poorly absorbed by mouth, almost all oral doses below are for precursors (the building blocks NMN and NR that the body turns into NAD+). No number here is a recommendation, and nothing on this page tells anyone how much to take. Read it as "in trial X, this dose did this." ## Doses Used in the Research Literature Across the controlled human literature, the most-replicated NMN dose is 250 mg/day — the dose that improved muscle insulin sensitivity over 10 weeks in prediabetic women [1] — with 300, 600 and 900 mg/day used in a 60-day multicenter dose-ranging trial where 600 mg/day was identified as optimal [3]. NMN has been studied up to roughly 1200 mg/day [research context]. Nicotinamide riboside is commonly studied at 250–1000 mg/day; the defining trial used 100, 300 and 1000 mg/day for 8 weeks [4], and NR has been safety-tested up to 3000 mg/day in the NR-SAFE study in Parkinson's disease [research context]. Nicotinamide has been studied at 500 mg twice daily for skin-cancer chemoprevention [research context]. For the injectable route, reported IV protocols run roughly 250–1000 mg per session over several hours, and one pharmacokinetic study used a 3 µmol/min continuous infusion over 6 hours [research context]. All of these are study protocols, not dosing advice. ## Routes studied and what they imply Four route families appear in the literature, and they differ sharply in evidence weight. Oral capsules and powders of NMN, NR and nicotinamide carry the bulk of controlled human evidence [4][3][1]. Intravenous NAD+ infusion is used in wellness settings but rests on limited, mostly pilot and retrospective data — covered on the [NAD injection and IV NAD+](/nad-injection) page. Subcutaneous and intramuscular NAD+ injection is compounded with minimal peer-reviewed pharmacokinetic data. Sublingual, intranasal, topical and transdermal patch products are marketed with little controlled evidence behind them [research context]. The pharmacokinetic split is the practical takeaway: infused NAD+ is cleared from plasma rapidly [research context], while oral precursors raise whole-blood NAD+ over days to weeks, an elevation that persists through chronic dosing in 8–12 week trials [4]. ## Reported Adverse Effects and Tolerability The NAD+ side effects on record cluster by route. Oral precursor trials generally reported good tolerability with no serious adverse events at tested doses — NR specifically produced no flushing and no significant adverse-event difference from placebo across 100–1000 mg/day [4]. The injectable route is where the symptoms concentrate: fast IV NAD+ has been associated with chest pressure, abdominal discomfort, flushing and nausea, which resolved on completing the infusion [research context]. Two further cautions belong here. Compounded injectable NAD+ carries a documented contamination risk — the FDA issued a Class I recall of a compounded NAD+ injection for elevated endotoxin [research context]. And a theoretical, context-dependent concern exists that boosting NAD+ could support the metabolism of existing cancers, since NAD+ fuels proliferating cells; NAD+ in oncology has dual roles, so caution is noted for cancer populations [research context]. None of this is medical advice — it is a summary of what the literature reports. ## Stability and product-quality notes NAD+ and NMN are hygroscopic and degrade with heat and moisture, and reconstituted injectable NAD+ should be kept cold and protected from light [research context]. On the consumer side, supplement-grade products vary widely in purity and actual content, and third-party testing is not guaranteed [research context]. These are quality observations from the literature and regulatory record, not endorsements of any product or any dose. --- A pinned-up research board on NAD+ — the redox coenzyme and its precursors NMN and NR tacked to their studies, the dose-dependent blood-NAD+ data marked confirmed and the unproven human endpoints flagged in red, with no clinic behind the board and nothing here infused, dispensed, or sold.