NAD+ Dosage in the Research Literature

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 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 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.