# NAD+ Dosage: Doses, Routes, and Tolerability Studied in the Precursor Literature | NAD+ > NAD+ dosage in research context: NMN 250-1200 mg/day and NR 250-3000 mg/day oral ranges, IV infusion protocols, half-life, and tolerability signals. Research framing only — no dosing advice. A research-context register of the doses, routes, and tolerability signals reported in the literature — documented as what trials administered, never as a recommendation to use any dose. ## Before the numbers This page lists doses that appear in published studies — and only that. Nothing here is a recommendation to take anything. Because oral NAD+ is poorly absorbed, the dose figures that matter are for the precursors (the building blocks the body converts to NAD+): NMN and NR. Each figure below carries its route, because an oral capsule dose and an IV infusion dose are not interchangeable. Where a number is human, it is tagged human; where it is from animals, it is tagged as such. Read these as documentation of what was studied. ## Doses studied in the NAD+ precursor literature The NAD+ dosage figures in the human record are precursor doses, oral, given as research context. **NMN (oral):** 250–900 mg/day in human RCTs, with up to 1200 mg/day studied; 250 mg/day is the most-replicated dose [1][3], and 600 mg/day was identified as the optimal dose in a 300/600/900 mg/day dose-finding RCT [3]. **NR (oral):** commonly 250–1000 mg/day, with up to 3000 mg/day tested for safety [4]. **IV NAD+ (wellness/clinical):** reported infusion protocols of roughly 250–1000 mg per session over several hours, and a formal pharmacokinetic study used a 3 µmol/min continuous infusion over six hours [10]. **Nicotinamide (NAM):** 500 mg twice daily has been studied in other contexts. Every one of these is a dose that was administered in a study — not a dose this digest endorses for anyone. ## How long NAD+ persists: infused clearance vs precursor elevation NAD+ has no single "half-life" number, because it behaves differently by route. NAD+ itself is not freely taken up intact by most cells; infused IV NAD+ is rapidly cleared, with a pilot study finding near-complete plasma removal within roughly the first two hours of infusion [10]. Oral precursors are different: they are absorbed and raise whole-blood NAD+ over days to weeks, with the elevation persisting through chronic dosing across 8–12 week trials [4][3]. So the relevant pharmacokinetic contrast is a short infusion spike versus a durable precursor-driven rise [10][4]. ## Tolerability and safety signals reported in trials Across the oral-precursor trials, NAD+ side effects were generally minor. NR at 100–1000 mg/day for eight weeks produced no flushing and no significant adverse-event difference from placebo at any dose, and did not elevate LDL cholesterol [4]; NR up to 3000 mg/day has been tested for safety [4]. NMN at 300–900 mg/day for 60 days reported no safety issues at any dose [3], and a systematic review of ten NMN trials found only minor adverse events (8.2%, independent of NMN) with no serious events [15]. The exceptions are on the injectable side: IV infusions can cause flushing, nausea, and chest or abdominal discomfort if run too fast, and compounded injectables have carried contamination risk — the FDA issued a Class I recall of a compounded NAD+ injection for elevated endotoxin [11]. Supplement-grade product purity also varies, and third-party testing is not guaranteed. ## Routes studied, and what each one tells you Four route families appear in the literature, with very different evidence weights. **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 clinics with limited, mostly pilot or retrospective data [10]. **Subcutaneous and intramuscular** compounded NAD+ injection has minimal peer-reviewed pharmacokinetic data [11]. **Sublingual, intranasal, topical, and transdermal patch** forms are marketed but have little controlled evidence. The route is part of the dose: a figure is only interpretable alongside the way it was given. See the [tolerability and safety signals](/dosage) above for how each route's risk profile differs. ## Stability and product quality in the literature Two practical points recur in the source material. First, stability: NAD+ and NMN are hygroscopic (they pull in moisture from the air) and degrade with heat and humidity, so reconstituted injectable NAD+ is described as needing cold storage and protection from light [8][11]. Second, product consistency: supplement-grade NMN and NR products vary widely in purity and actual content, and third-party testing is not guaranteed, which is one reason published trials — where the material is characterized — are a cleaner read of what a dose does than a shelf product is [8]. Neither point is a dosing instruction; both are documented context for interpreting the dose figures above. The dose-finding signal is worth restating because it is the closest the literature comes to a defined oral target: in the multicenter NMN RCT, 300, 600, and 900 mg/day all raised blood NAD+ versus placebo, but 600 mg/day was identified as the optimal dose on the trial's combined endpoints [3]. That is a study conclusion about a study population, not advice for a reader. ## How much NAD should I take? This digest gives no personal dosing advice. For research context only: studied doses span NMN 250–1200 mg/day and NR 250–3000 mg/day orally; 250 mg/day NMN is the most-replicated dose [1] and 600 mg/day was identified as optimal in one dose-finding RCT [3]. Those are descriptions of what trials administered, not a recommendation for any individual. --- Documentation of the NAD+ record: the precursor trials logged green, the IV and injection gaps flagged amber, the species and route on every figure — no clinic behind the docs and nothing here dispensed, dosed, or sold.