NAD+ Dosage and Side Effects: What Studies Actually Used

There is no established dose for injectable or IV NAD+. That is the finding, not a preamble to one. Our NAD+ evidence review covers why the outcome literature is empty for this route; this article covers the narrower and more practical question that review deliberately leaves alone — what was actually put into a person, at what rate, by which route, in the studies that do exist. The answer is unusual for a compound this heavily sold: NAD+ is not short of published numbers. It is short of published numbers about the product this site's 38-seller NAD+ board actually ships.

What the one human study of infused NAD+ itself actually administered

Exactly one published human study has put NAD+ itself — not a precursor — into a person's bloodstream and measured what happened. It is a pharmacokinetic pilot, published as a plain journal article rather than a registered clinical trial, and a 2026 systematic review that screened sixteen years of literature classified it as "contextual evidence only" precisely because it measured blood and urine chemistry rather than any clinical outcome¹.

Its regimen, stated in the paper's own words, is "a 6 h 3 μmol/min NAD+ intravenous (IV) infusion"². Note what that is and is not. It is an infusion RATE and a duration, not a milligram figure — the study reports micromoles per minute because it was tracking metabolite kinetics, not establishing a therapeutic amount. Converting it takes one step of arithmetic this article does openly rather than quietly: 3 μmol/min over 360 minutes is 1,080 μmol, and at NAD+'s molar mass of 663.4 g/mol³ that works out to roughly 717 mg delivered across six hours. That number is this article's own unit conversion of the study's stated regimen, not a dose the study recommended, endorsed, or tested against any alternative.

What the study found at that rate is the part most often left out of the marketing: "no change in plasma [NAD+] or metabolites... were observed until after 2 h"². The authors' own reading is that "at an infusion rate of 3 μmol/min NAD+ is rapidly and completely removed from the plasma for at least the first 2 h," with the metabolite pattern "consistent with NAD+ glycohydrolase and NAD+ pyrophosphatase activity" — the body's own NAD+-degrading enzymes clearing the infused molecule. Whatever else this establishes, it does not establish that a given rate produces a given blood level in a predictable way, which is the minimum a dosing standard would require.

The only real-world NAD+ IV number in the peer-reviewed literature — and the side effects that came with it

One more human number exists, and it comes from a retrospective review of electronic medical records at a commercial IV-therapy chain rather than from a trial⁴. Its methods state the regimen plainly: "Participants received four consecutive days of 500 mg NAD+ IV or NR IV, with 30 days follow-up." That is the only published, real-world NAD+ IV dosing schedule this review located, and it is worth being precise about its status — a retrospective chart review at a single commercial operator, authored by employees of that operator, with no randomization and no control condition beyond the nicotinamide riboside comparison group.

It is also, by default, the entire published human side-effect record for this route. Its own results: "Participants that received NAD+ IV reported moderate to severe gastrointestinal symptoms, increased heart rate, and chest pressure during infusions," while the NR IV group reported only "minor tongue, jaw, and arm tingling and mild cramping." Every symptom in both groups "resolved upon infusion completion." The most concrete consequence is in the infusion times: the NAD+ group's infusions averaged 97 minutes against 37 minutes for NR IV, because the moderate-to-severe symptoms forced clinicians to slow the drip. On standard safety labs, "no significant changes were observed in ALT, AST, hsCRP, BUN/creatinine, or TSH." Two findings the study itself flags rather than smooths over: alkaline phosphatase "decreased significantly in the NAD+ IV group only, with values remaining within normal reference ranges," and over the 30-day window HDL-C fell significantly in the NAD+ group while HbA1c fell significantly in the NR group — differences the authors call "variable" and say "warrant further investigation."

Read as a dosing document, this study's own closing sentence is the most important one in it: "Additional studies are needed to evaluate dosage and effectiveness beyond 30 days." The people who published the only real-world NAD+ IV dose in the literature do not present it as an established one.

The oral precursor doses are the only ones with a randomized dose-response behind them — and they are a different molecule

This is where the numbers people actually find when they search "NAD dosage" come from, and it is critical to keep straight that they describe nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN) — precursors the body converts into NAD+ — not NAD+ itself, and oral capsules, not an injection or an IV bag.

• •NR, 100 / 300 / 1,000 mg daily for 8 weeks. A randomized, double-blind, placebo-controlled trial in overweight but otherwise healthy adults reports that those three doses "dose-dependently and significantly increased whole blood NAD+ (i.e., 22%, 51% and 142%) and other NAD+ metabolites within 2 weeks," with the increases maintained for the rest of the study⁵. On safety, the same trial found "no reports of flushing and no significant differences in adverse events between the NR and placebo-treated groups or between groups at different NR doses," and NR "did not elevate low density lipoprotein cholesterol or dysregulate 1-carbon metabolism."
• •NMN, 300 / 600 / 900 mg once daily for 60 days. A randomized, multicenter, double-blind, placebo-controlled, explicitly dose-dependent trial in 80 healthy middle-aged adults found blood NAD raised significantly at every dose versus both placebo and baseline, "highest in the groups taking 600 mg and 900 mg NMN"⁶. Its own conclusion is the detail that most "higher is better" dosing advice gets exactly backwards: "Clinical efficacy expressed by blood NAD concentration and physical performance reaches highest at a dose of 600 mg daily oral intake." Nine hundred milligrams was not better than six hundred. On safety: "No safety issues, based on monitoring adverse events (AEs), laboratory and clinical measures, were found, and NMN supplementation was well tolerated."
• •NR, 250 mg uptitrated to 1,000 mg twice daily. An open-label, non-randomized pharmacokinetic study in 8 healthy volunteers — reported here as the uncontrolled study its own title says it is — escalated from 250 mg on days 1 and 2 to a peak of 1,000 mg twice daily by days 7 and 8, and found whole-blood NAD+ increased by 100% at steady state, with "no adverse events"⁷.
• •A 2026 head-to-head that changes how to read all of the above. A randomized, open-label, placebo-controlled study in 65 healthy participants compared 14 days of NR, NMN, and plain nicotinamide directly, and found that NR and NMN, "but not Nam, comparably increases circulatory NAD+ concentrations in healthy adults"⁸. Which precursor you take matters; the study's own model attributes NR's and NMN's effect partly to gut microbial conversion, a pathway an injection bypasses entirely.

What that means for the product this board actually sells

Put the three tiers next to each other and the shape of the gap is specific rather than vague. The oral precursors have a randomized, placebo-controlled, dose-ranging human record with a measured ceiling — and they are a different molecule taken by a different route. NAD+ itself, infused, has one pharmacokinetic pilot reporting a rate rather than a dose, and one retrospective chart review reporting a commercial clinic's 500 mg × 4 days schedule along with the symptoms that schedule produced. Nasal-spray and oral-liquid NAD+, both sold across this board's roster, have no located human dosing study of any kind for either route — a search combining NAD+ with intramuscular, subcutaneous, and nasal administration in humans, re-run for this article, returned nothing relevant.

The 2026 systematic review that screened 113 eligible studies published between January 2010 and October 2025 states the underlying reason in one sentence: "No eligible outcomes trials evaluated intravenous or intramuscular NAD⁺ itself for anti-aging or wellness indications"¹. A dose becomes established when trials test several of them against each other and against placebo for an outcome. For injected NAD+, that has not happened, so there is nothing to establish a dose from.

The regulatory picture, re-checked

A live DailyMed structured-product-label search for "NAD" returns 93 results, re-verified for this article on 2026-08-07 and unchanged from this site's earlier check: every result is Nadolol (an unrelated beta-blocker matched on the letters "NAD"), a homeopathic combination remedy listing "Nadidum" among a dozen other ingredients, or an over-the-counter cosmetic or patch listing⁹. There is no FDA-approved NAD+ drug product of any kind, which means there is no agency-reviewed label anywhere carrying a dose, a maximum, an infusion rate, or a monitoring instruction for this compound. Unlike the peptides in this site's FDA 503A compounding status tracker, NAD+ is not a novel synthetic peptide under Pharmacy Compounding Advisory Committee nomination review — it is a naturally occurring coenzyme in a different regulatory category, so its absence from those proceedings is not an earlier stage of the same process.

What this means if you're looking for an NAD+ dose

There is no validated NAD+ dosing schedule for injection, IV, nasal spray, or oral liquid that this site or any other honest source can hand you — not because the numbers are being withheld, but because the studies that would produce them have not been run. What exists, stated exactly as it appears in the literature: one 6-hour IV infusion at 3 μmol/min in a pharmacokinetic pilot that detected no plasma change for the first two hours; one commercial clinic's retrospective record of 500 mg IV daily for four consecutive days, with moderate-to-severe gastrointestinal symptoms, raised heart rate, and chest pressure serious enough to nearly triple the infusion time; and a genuine randomized dose-response record for oral NR and NMN, which are related but different molecules whose measured benefit in the largest dose-ranging trial peaked at 600 mg rather than climbing with dose.

For the efficacy side of the same evidence gap, see our NAD+ evidence review; for the oral precursor most often confused with NAD+ itself, our NMN review. NAD+'s most common cross-sell on this site's boards has the same route-by-route dosing problem for different reasons — see our glutathione dosage article and its evidence review. For the same non-recommendation method applied to peptides whose foundational studies also decline to publish a dose, see our KPV dosage article and our BPC-157 dosage article.