NAD dosage is a question without a label to answer it. NAD+ is not an approved drug, and pharmacies compound it under an FDA interim policy. [8] What exists instead is a short list of human studies, each with its own amount, route and schedule.
This page sets those amounts side by side. It separates NAD+ itself from the oral building blocks that the body turns into NAD+. It also answers the timing question with blood measurements, the only kind these studies took.
Doses given by vein
Three human studies state an intravenous NAD+ dose. They differ by about 75-fold, and none was designed to find the right amount.
The 6-hour pilot gave 750 mg of NAD+ in saline to 8 healthy men aged 30 to 55 [1]. The infusion ran at about 2 mg a minute. The authors wrote that the dose was derived empirically and reflects a common clinical regimen. Three more men received saline as controls.
A chart review from a commercial wellness clinic covered clients who received 500 mg of NAD+ by vein on four days in a row [2]. Only 6 people were in the NAD+ group. The authors were employees of the clinic that gave the drips, and they call for further study of dosage.
The only randomized trial of the three used far less. It gave 10 mg of NAD+ a day by vein for 7 days to adults with heart failure from ischemic cardiomyopathy, against a placebo infusion [3]. At 1 month, the mean ejection fraction was 45.44% with NAD+ and 42.44% with placebo (p = 0.024), in 180 enrolled patients.
| Study | Who | What the study used | Design |
|---|---|---|---|
| 6-hour infusion pilot (2019) | 8 healthy men, 3 saline controls | 750 mg over 6 hours, once | Pilot, blood and urine only |
| Clinic chart review (2026) | 6 clinic clients | 500 mg a day for 4 days | Retrospective records |
| Heart failure trial (2026) | 180 adults with heart failure | 10 mg a day for 7 days | Randomized, placebo-controlled |
How those amounts were tolerated is a separate question. The NAD side effects page covers what people reported during each kind of drip. The full IV record, including what the drips did not measure, is in NAD IV therapy.
Injection under the skin: no tested dose
Compounded NAD+ is also prescribed as a shot under the skin. No human study indexed in PubMed has measured what a subcutaneous NAD+ dose does to blood levels or to any outcome. Any dose on a vial or a prescription for that route comes from practice, not from a trial.
That gap is the main thing to know about NAD injection dosage. It does not mean the route is unsafe. It means nobody has published the numbers. What the injection claims rest on is laid out in NAD+ injections.
Oral precursor doses, and why they are not NAD+ doses
The best-measured doses belong to precursors: nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN). The body converts both into NAD+. Their milligrams cannot be swapped for NAD+ milligrams, because the molecules differ and so does the route.
One 8-week NR trial compared three doses in overweight but healthy adults [4]. Participants took 100, 300 or 1,000 mg a day, or placebo. Whole-blood NAD+ rose with the dose, and the rise held for the rest of the study. The trial was funded by the company that sells the NR used.
+22%
whole-blood NAD+ with 100 mg NR a day, within 2 weeks
Conze 2019
+51%
whole-blood NAD+ with 300 mg NR a day, within 2 weeks
Conze 2019
+142%
whole-blood NAD+ with 1,000 mg NR a day, within 2 weeks
Conze 2019
A crossover trial in healthy middle-aged and older adults used 500 mg of NR twice a day for 6 weeks [6]. NAD+ in circulating immune cells rose about 60% compared with placebo. A small open-label study stepped 8 volunteers up from 250 mg to 1,000 mg twice daily over 9 days, and blood NAD+ doubled at steady state [5].
For NMN, a 60-day trial randomized 80 healthy middle-aged adults to 300, 600 or 900 mg a day, or placebo [7]. Blood NAD rose in every NMN group at day 30 and day 60, and was highest at 600 and 900 mg. How NMN compares with NAD+ itself is covered in NMN vs NAD.
How long NAD takes to show up in the blood
Timing depends on the route, and the studies measured blood levels, not how people felt.
By vein, the pilot found no change in plasma NAD+ for the first 2 hours of the 750 mg infusion [1]. The authors concluded the infused NAD+ was being removed from plasma rapidly and completely. Only at the end of the 6 hours had NAD+ climbed, to about 398% above baseline.
By mouth, the precursors took days to weeks. Blood NAD+ had risen within 2 weeks in the three-dose NR trial [4]. NMN raised blood NAD by the first check at day 30 [7]. None of these studies measured when, or whether, a person would notice any change.
What this means if you are prescribed NAD+
A prescription sets the dose, and the studies above cannot confirm or overrule it. They show the range that has been given to people, and how little of it was tested for effect.
Worth asking a prescriber: which route, what amount per session, and how often. For a drip, ask how long it runs: in the clinic review, symptoms stretched NAD+ drips to 97 minutes on average [2].
Sellers that prescribe NAD+ by injection or by nasal spray are compared on the NAD+ injection or nasal spray board. The longevity board ranks prescribers of NAD+ and glutathione together. Other options sit on the longevity goal page.
Glutathione, the other compound on that board, has its liver studies covered in glutathione for liver.