# NAD+ Dosage in Research: Doses Studied for NMN, NR, and Infusions > NAD+ dosage in the research literature: the precursor doses studied in named human populations (NMN, NR, nicotinamide) and infusion protocols. Context only, no dosing instructions. What trials administered, to whom, by which route — set out as research context, with no human dosing recommendation. ## Before the details This page is a map of doses *studied*, not a dosing guide. It gives no instruction to take anything. Because oral NAD+ is poorly absorbed, the human dosing literature is really a precursor literature — trials gave people NMN or NR (building blocks the body converts into NAD+), not NAD+ itself. Below, each figure is tied to the study that used it and the population it was tested in. Treat the numbers the way you would read distances on an atlas: they tell you where researchers have been, not where you should go. ## Doses Used in NAD+ and Precursor Research Across controlled human trials, the oral-precursor doses cluster into recognizable ranges. NMN has most often been studied at 250-900 mg/day, with 250 mg/day the single most-replicated dose; a 2023 multicenter trial compared 300, 600 and 900 mg/day over 60 days and named 600 mg/day the optimal dose for raising blood NAD+ [3]. NR is commonly studied at 250-1000 mg/day, with a dose-finding trial measuring whole-blood NAD+ gains of 22%, 51% and 142% at 100, 300 and 1000 mg/day over eight weeks [4]; the high end of NR's tested range reached 3000 mg/day in a 30-day Parkinson's-disease safety trial [6]. Nicotinamide has been studied at 500 mg twice daily in a dermatology context [8]. These are descriptions of what specific trials administered to specific groups — middle-aged adults, prediabetic women, Parkinson's patients — not a recommendation for any reader. ## Routes studied and how NAD+ behaves in the body The route determines almost everything about NAD+ pharmacology. Oral precursors (NMN, NR, nicotinamide capsules or powder) account for the bulk of controlled human evidence; they are absorbed and raise whole-blood NAD+ over days to weeks, with the elevation sustained through chronic dosing in 8-12 week trials [4]. NAD+ given by vein behaves very differently: infused NAD+ is rapidly cleared from plasma, and a pilot pharmacokinetic study found near-complete plasma removal within roughly the first two hours of infusion. Subcutaneous and intramuscular NAD+ injections are compounded with minimal peer-reviewed pharmacokinetic data, and sublingual, intranasal, topical and transdermal-patch formats are marketed with little controlled evidence behind them. The infusion route is mapped in full on the [IV NAD therapy research](/iv-nad) page. ## Stability and product quality NAD+ and NMN are hygroscopic and degrade with heat and moisture, which is a practical reason supplement quality varies. Reconstituted injectable NAD+ should be kept cold and protected from light, and compounded injectables carry contamination and endotoxin risk — the FDA has issued a Class I recall of a compounded NAD+ injection over elevated bacterial endotoxin. Supplement-grade oral products also vary widely in purity and actual content, and third-party testing is not guaranteed. These quality questions sit alongside the safety record on the [NAD+ safety and side effects](/nad-safety) page. ## Is taking NAD orally effective? Oral NAD+ itself is poorly taken up intact, so oral precursors (NMN, NR) are the rational approach — and trials show they dose-dependently raise blood NAD+ (NR by 22%, 51% and 142% at 100, 300 and 1000 mg/day) [4]. They are effective at raising NAD+; translation to clinical outcomes is still mixed [7]. ## How much NAD should I take? This digest gives no human dosing instruction. For context only, trials have studied NMN at 250-900 mg/day (250 mg most replicated) [3], NR at 250-1000 mg/day and up to 3000 mg/day in the NR-SAFE Parkinson's trial [6], and nicotinamide at 500 mg twice daily [8] — descriptions of what was studied in named populations, not a recommendation. ## What is the best time to take NAD, morning or night? No cited trial establishes an optimal time of day. NAD+ salvage (via NAMPT) follows a circadian rhythm and is induced by exercise, which is sometimes offered as a rationale for timing [5], but the human trials did not test morning-versus-night dosing. No timing instruction is given here. --- A dusk-drawn atlas of the NAD+ literature — the coenzyme charted apart from the NMN and NR precursors that rebuild it, the oral trials kept off the rapidly-cleared IV route, and the contested NMN status marked at the frontier; no clinic surveys behind this map and nothing here is dosed, compounded, prescribed, or sold.