# NAD+ Dosage in the Research Literature: NMN, NR, and Injectable Route Ranges > NAD+ dosage as studied: oral NMN 250-900 mg/day, NR 250-1000 (up to 3000) mg/day, plus injectable and IV NAD+ protocols. Research context and tolerability only — no human dosing instructions. The oral-precursor and injectable dose ranges that published studies used, with their tolerability data — context for reading the research, not a recommendation. ## Before the details This page lists the NAD+ dosage figures that appear in published studies — what researchers gave, to which species, by which route. It exists so you can read the literature accurately, and it is not a dosing guide for any person. Because plain NAD+ is poorly absorbed when swallowed, almost all oral dosing in trials is of precursors (building blocks like NMN and NR). No human dosing instruction is given or implied anywhere on this site. ## Doses studied in the research literature Oral NMN in human trials has ranged from 250 to 900 mg/day, with 250 mg/day the most-replicated dose and up to roughly 1200 mg/day studied. The 250 mg/day, ten-week NMN trial measured muscle insulin sensitivity [1]; the 300-900 mg/day, 60-day multicenter trial identified 600 mg/day as the optimal dose for raising blood NAD+ and improving walking distance [3]. Nicotinamide riboside has commonly been studied at 250-1000 mg/day, with the 100/300/1000 mg/day dose-response trial showing the 22/51/142% whole-blood NAD+ rise [4], and up to 3000 mg/day tested for safety in a dedicated tolerability study in Parkinson's disease. Nicotinamide (NAM) has been studied at 500 mg twice daily for skin-cancer chemoprevention. These figures are research context, drawn from the cited trials — not personal recommendations. One pattern is worth flagging for anyone reading dose figures: the route is inseparable from the number. An oral 600 mg NMN dose [3] and a milligram-per-kilogram intraperitoneal NAD dose in a mouse [10] are not on the same scale and do not convert into one another. Across the human oral literature, the doses that have been studied cluster in the few-hundred-milligram-per-day range for NMN and the few-hundred-to-one-thousand-milligram range for NR, and the reliable readout in every case is whole-blood NAD+, because direct tissue NAD+ sampling in humans is invasive and rare. ## Injectable and IV NAD+ routes in the literature An **NAD injection** delivers NAD+ itself rather than a precursor, by the intravenous, subcutaneous, or intramuscular route. Reported IV protocols describe infusions of roughly 250-1000 mg per session over several hours, and one pharmacokinetic study used a 3 µmol/min continuous infusion over six hours. The controlled human evidence for these routes is far thinner than for oral precursors. The pharmacokinetics are the key limitation: a pilot study found infused NAD+ was near-completely removed from plasma within the first roughly two hours of infusion. Animal IV data are more dramatic — intravenous NAD+ at 10-20 mg/kg reduced myocardial infarct size by about 85% at 20 mg/kg in a rat ischemia-reperfusion model [9] — but that is a rat result, not a human dosing basis. The injectable route is covered in depth on the [IV NAD therapy](/iv-nad) page. ## Half-life and how long blood NAD+ stays elevated NAD+ is not freely taken up intact by most cells, so "half-life" behaves differently by route. Infused IV NAD+ is cleared from plasma rapidly — near-complete removal within about two hours in the pilot pharmacokinetic data. Oral precursors behave on a different timescale entirely: absorbed over hours, they raise whole-blood NAD+ over days to weeks, and the elevation persists through chronic dosing across the 8-12 week trial windows [3][4]. The practical reading is that oral precursors sustain a blood-NAD+ increase, while an IV bolus of NAD+ does not linger in plasma. ## Tolerability and safety signals in trials The most common query about **NAD+ side effects** is whether daily use is tolerated. In controlled trials, oral precursors were generally well tolerated over 8-12 weeks: NR at up to 1000 mg/day produced no flushing and no significant adverse-event difference from placebo [4], and the NMN dose-response trial reported no safety issues at any dose up to 900 mg/day [3]. The documented safety concerns cluster on the injectable side. Infusion-related effects — flushing, nausea, chest or abdominal discomfort — are typically transient and tied to infusion rate. More seriously, compounded injectable NAD+ carries a contamination risk: the FDA has issued a Class I recall of a compounded NAD+ injection for elevated bacterial endotoxin. Supplement-grade oral products also vary widely in purity and actual content, and third-party testing is not guaranteed. A theoretical caution also applies in cancer populations, where boosting NAD+ could support proliferating cells; NAD+ has dual, context-dependent roles in oncology. ## Stability and storage notes from the literature NAD+ and NMN are hygroscopic — they pull in moisture — and degrade with heat and humidity, which is why powdered precursors are kept dry and cool. Reconstituted injectable NAD+ is less stable still: it should be kept cold and protected from light. These handling facts are part of why the compounded injectable route is quality-sensitive; a preparation that degrades or is contaminated before use is the failure mode behind the Class I endotoxin recall noted above. None of this is storage advice for a consumer product — it is context for reading how the studied forms behave. ## How much NAD do studies use? Trials have used oral NMN at 250-900 mg/day [1][3] and NR at 250-1000 mg/day, with up to 3000 mg/day tested for safety [4]. These are research doses reported for context, not a recommendation for any person. This site gives no human dosing instruction; the figures exist only so the cited studies can be read accurately. ## What is the best time to take NAD, morning or night? Trials have not established an optimal time of day. NAMPT, a key salvage enzyme, follows a circadian rhythm [11], which makes timing a legitimate research question, but no study summarized here compared morning against night dosing. There is no evidence-based time-of-day answer to give. --- A nocturnal traverse of the NAD+ literature — the heart, kidney, and muscle studies cited to source, the precursor-not-NAD+ distinction kept exact, and the trail marked where the human evidence thins; no clinic at the trailhead and nothing here dispensed, prescribed, or sold.