NAD+ Dosage Guide: How Much Per Day, by Form and Route

If you search "NAD+ dosage," you'll get a confident-sounding number from almost every supplement brand — and they rarely agree. The honest answer is more useful, and a little less tidy: the doses people quote come from a small set of human trials that measured safety and a blood biomarker (NAD+ levels), not whether you live longer, feel younger, or lose fat. So a dose can be "studied" and still tell you nothing about whether it works for the thing you're hoping for.

This guide gives you the actual numbers from the human studies, organized by form — oral nicotinamide riboside (NR), oral nicotinamide mononucleotide (NMN), niacin and nicotinamide, and IV/injectable NAD+ — and is clear about exactly what each number does and doesn't prove. For the bigger picture of what NAD+ supplementation has and hasn't shown, start with our pillar guide to the NAD+ evidence.

The one rule that matters most: dose is anchored to *what was measured*

Almost every NAD+ human trial to date has a primary endpoint that is either tolerability (did people get side effects?) or a biomarker (did blood or muscle NAD+ go up?). Very few measured a real-world outcome, and the ones that did mostly came back null or mixed. So when a label says "clinically studied dose," what that almost always means is: this dose was shown to be safe and to raise NAD+ in the blood. That is a real and worthwhile thing to know — but it is not the same as "this dose makes you healthier."

Two consequences follow from that, and they run through this entire guide:

• •More is not automatically better. NAD+ blood levels tend to plateau, and the dose-response for raising the biomarker often flattens out well before the highest doses people take. Bigger doses mostly buy you more cost and more flush or GI upset, not more proven benefit.
• •"Studied for safety" is short-term. Most trials ran weeks to a few months. Long-term, high-dose human safety data are thin for NR and NMN. That uncertainty is a reason for restraint, not a license to megadose.

These are supplements, not approved drugs, and none of the doses below is a treatment for any disease. Use this as background for a conversation with a clinician — especially if you're pregnant, on medication, or managing a health condition.

Oral nicotinamide riboside (NR): roughly 250–1,000 mg/day

NR is the NAD+ precursor with the most controlled human dosing data, largely because the branded ingredient (Niagen) funded formal safety and pharmacokinetic work.

The foundational study showed that a single oral dose of NR raises blood NAD+ in humans in a dose-dependent way — the first clear demonstration that an oral precursor actually moves the biomarker¹. A dedicated ascending-dose pharmacokinetic study then gave healthy adults 250 mg, 1,000 mg, and 2,000 mg and confirmed NAD+ rose with dose while the compound was well tolerated across that range². Formal safety work supports the commonly sold band: a randomized trial dosed NR up to 1,000 mg/day and found it safe, with blood NAD+ rising and a favorable tolerability profile³, and an 8-week study comparing 100, 300, and 1,000 mg/day of nicotinamide riboside chloride established dose-dependent NAD+ increases without meaningful safety signals⁴. The manufacturer's toxicology package defined a no-observed-adverse-effect level in animals that underpins the human upper doses⁵.

Higher and split dosing has also been tested: trials in overweight/obese men used 1,000 mg twice daily (2,000 mg/day)⁶, and a study in aged adults gave 1,000 mg/day and confirmed it raised the muscle NAD+ metabolome⁷. The recurring finding in these higher-dose studies, though, is telling — NR reliably raised NAD+ but did not improve the functional or metabolic outcomes the researchers hoped for (insulin sensitivity, muscle mitochondrial function), and even a phase I trial in Parkinson's disease using 1,000 mg/day was designed mainly to confirm target engagement, not to prove a clinical benefit¹⁴.

Bottom line for NR: the human-studied range is roughly 250–1,000 mg/day, with safety data extending to 2,000 mg/day. NAD+ goes up across that band; proven outcomes do not scale with the dose. Going above ~1,000 mg/day buys little but cost — the trial-by-trial detail behind that band sits in our nicotinamide riboside dosage guide. We compare NR head-to-head with NMN in NMN vs NR.

Oral nicotinamide mononucleotide (NMN): roughly 250–900 mg/day

NMN's human dosing is anchored to a cluster of small dose-ranging trials, mostly from Japan and China. An early single-dose safety study in men gave 100, 250, and 500 mg and found NMN was safe with no problematic changes in clinical parameters⁸ — establishing tolerability but, again, not outcomes.

The most-cited dose-ranging trial randomized healthy middle-aged adults to 300, 600, or 900 mg/day for 60 days and reported that blood NAD+ rose dose-dependently and the higher doses were well tolerated, with a walking-distance and biological-age signal that the authors themselves framed cautiously⁹. A separate safety study confirmed that oral NMN up to 1,250 mg/day efficiently raised blood NAD+ metabolites and was safe over the test period¹⁶. In a tighter, mechanism-focused trial, 250 mg/day of NMN improved muscle insulin sensitivity in prediabetic women — a genuine controlled finding, but in a specific population and on a surrogate endpoint, not weight or disease outcomes¹⁰. An exercise trial in amateur runners compared 300, 600, and 1,200 mg/day and reported aerobic-capacity differences, though it was small and unblinded in ways that limit confidence¹¹.

At the higher end, a pharmaceutical-grade NMN (MIB-626) was tested at 1,000 mg once or twice daily in overweight/older adults; it robustly raised NAD+ but was explicitly described as a physiologic study — biomarker movement, not a clinical-outcome win¹².

Bottom line for NMN: the studied range is roughly 250–900 mg/day (with safety data to ~1,250 mg), and 300–600 mg/day captures most of what the trials used. As with NR, NAD+ rises reliably; durable human outcomes remain unproven. (NMN also sits under a regulatory cloud in the US after the FDA's position that it can't be sold as a supplement — context we cover in NMN vs NAD+ and our best NMN supplements roundup. And if you're wondering whether to pair NMN with a methyl donor at these doses, see should you take TMG with NMN?. Once you've settled on a dose, the best time to take NMN is a smaller question than the marketing suggests — consistency matters more than the hour. And ignore the per-kilogram calculators — these trials used flat doses, not body weight, as we explain in NMN dosage by body weight; our own NMN dosage calculator hands back the studied flat band rather than scaling a number to your mass. If you take metformin, dosing isn't the only question — see whether you can take NMN with metformin and what the thin combined evidence shows.)

Niacin and nicotinamide: the old, cheap NAD+ precursors

Niacin (nicotinic acid) and nicotinamide (niacinamide) are the original vitamin-B3 NAD+ precursors, and they're dramatically cheaper than NR or NMN — but they come with their own dosing realities.

The recommended dietary allowance for niacin is only about 14–16 mg/day (as niacin equivalents) — enough to prevent deficiency. The doses studied for raising NAD+ are far higher and behave differently:

• •Niacin (nicotinic acid) was tested at escalating doses up to 750–1,000 mg/day in patients with a mitochondrial myopathy and genuine NAD+ deficiency, where it corrected systemic NAD+ levels and improved muscle performance — a striking result, but in a rare disease state, not in healthy people¹³. Niacin's signature limitation is the flush: a prostaglandin-mediated reaction (acting through skin Langerhans cells and the GPR109A receptor) that causes intense warmth, redness and itching, which is why high-dose niacin is hard to tolerate¹⁵.
• •Nicotinamide (niacinamide) doesn't cause flushing, which is why it shows up in NAD+ blends. But at high chronic doses it carries its own caution — large amounts can raise liver-enzyme concerns and may blunt some of the very NAD+-dependent (sirtuin) signaling people are chasing. It's effective at correcting deficiency, but not a free lunch at megadoses.

Bottom line for B3: these forms do raise NAD+ and cost pennies, but flush (niacin) and high-dose liver/signaling concerns (nicotinamide) make them less popular as "NAD+ optimizers," even though the precursor logic is the same. Cheaper isn't automatically worse — but the tolerability tradeoffs are real.

IV NAD+: clinic protocols, weakest evidence

Intravenous NAD+ is the most aggressively marketed and the least supported by controlled data. Clinic protocols vary enormously — commonly cited drips run 250 mg to 1,000 mg per session, with some "high-dose" programs advertising multi-day courses totaling several grams. These numbers come from clinic marketing and small case reports, not from dose-ranging trials with real endpoints. There is no established, evidence-based IV NAD+ dose because there are essentially no rigorous outcome trials to anchor one. Infusing too fast reliably causes chest tightness, nausea and a flushing/anxiety sensation, which is why drips are run slowly over hours.

We go deep on what's actually known (and what isn't) in NAD+ IV therapy: evidence and cost. The short version: the route is plausible for getting NAD+ into the blood, but the dose is set by clinics and convenience, not by trials — so treat any specific IV number with skepticism.

Injectable NAD+ dosage: the chart everyone copies, and where it came from

Search "NAD+ injection dosage chart" and you get a dozen tidy tables that agree with each other closely enough to look like consensus — 50 mg to start, 100 mg for maintenance, 200 mg for "advanced" protocols, two to five times a week. They are not consensus. They are the same clinic marketing copied between med-spa blogs, and not one of them cites a dose-ranging study, because none exists for the injected route. This section reports those numbers because you will meet them everywhere, and then says plainly what they are.

Per day vs per week. Providers usually express injectable NAD+ as a per-dose amount plus a cadence rather than a daily figure, because almost nobody injects daily. A commonly advertised at-home protocol is 50–100 mg subcutaneously, two to five times a week — which works out to roughly 100–500 mg per week, and somewhere between 400 and 2,200 mg a month. That is a wide band, and the width is the finding: there is no pharmacological reason to prefer any point in it, because no study has compared them.

The 500 mg and 1000 mg vial question. Compounded NAD+ ships as a powder in a vial of a stated strength, most often 500 mg or 1000 mg, which is reconstituted with bacteriostatic water before use. Very few sellers publish either figure — Yucca Health, which states 100 mg/mL on the product itself and Taurus Meds, which publishes 200 mg/mL in a 5 mL bottle, are the exceptions rather than the rule. The vial size is a packaging decision, not a dose: a 1000 mg vial is not a 1000 mg dose, it is roughly ten to twenty doses. How many milligrams end up in the syringe depends on the concentration the pharmacy's instructions produce — a 500 mg vial in 5 mL of bacteriostatic water gives 100 mg/mL, so 50 mg is half a millilitre, which is the 50-unit mark on a U-100 insulin syringe. Change the water and the same dose lands on a different mark. Our NAD+ injection dosage calculator does that conversion, and deliberately refuses to hand you a milligram figure of its own.

Where the injection goes. Subcutaneous means into the fat layer rather than muscle, and provider instructions typically nominate the abdomen (a couple of inches clear of the navel), the outer thigh, or the back of the upper arm, rotating sites between doses to avoid irritating one spot. Injection-site reactions — redness, a lump, tenderness — are among the most commonly reported effects, and rotation is the standard mitigation. Treat any of that as a description of what providers instruct, not as instruction from us: the person who prescribed your vial is the person whose written directions govern, and if theirs differ from anything here, theirs win.

The flush is a rate phenomenon. The best-documented effect of putting NAD+ directly into the body is what happens when it goes in too fast — chest tightness, flushing, nausea, cramping and lightheadedness, which is exactly why IV drips are stretched over hours rather than minutes. Injected doses are kept small partly for the same reason. If a dose provokes that reaction, it is a conversation with the prescriber, not something to push through.

And the honest bottom line for this route. Everything above is a report on prevailing practice, not a dose recommendation, because there is nothing to recommend from. There is no published outcome trial of subcutaneous or intramuscular NAD+ — and no published human pharmacokinetic study of it either, so we do not even know what blood levels an injection produces. That is a genuinely unusual evidence position for a product this widely sold, and we set it out in full in what a NAD+ injection is, and what the research shows. Note the contrast with the oral sections above: NR and NMN, the cheapest things in this category, are the ones with the ascending-dose pharmacokinetics and the randomised dose-finding trials.

A realistic dosing summary (not medical advice)

Putting the trials together, here's what the human evidence actually supports as studied doses — each of which moved the NAD+ biomarker and was generally tolerated, with outcomes still unproven:

• •Oral NR: ~250–1,000 mg/day (safety data to 2,000 mg/day).
• •Oral NMN: ~250–900 mg/day (safety data to ~1,250 mg/day); 300–600 mg/day is the common research band.
• •Niacin: RDA is ~14–16 mg/day; NAD+-raising doses studied at hundreds of mg but flush-limited.
• •Nicotinamide: raises NAD+ cheaply, no flush, but high chronic doses carry liver/signaling cautions.
• •IV NAD+: no evidence-based dose; clinic protocols (~250–1,000 mg/session) are marketing-derived, not trial-derived.
• •Injectable (SubQ/IM) NAD+: no evidence-based dose either; the advertised band is ~50–100 mg per dose, 2–5×/week (~100–500 mg/week), and it comes from provider marketing, not a study.

Three honest caveats to carry with those numbers. First, "studied" means studied for safety and NAD+ levels — not for living longer or feeling better. Second, the dose-response for the biomarker plateaus, so chasing ever-higher doses is mostly chasing cost and side effects. Third, long-term high-dose safety is genuinely unknown for NR and NMN; the trials were short. Before starting any of these, talk to a clinician — and review the realistic NAD+ side effects first.

If you want to see how specific products map onto these studied doses, with third-party-testing and value caveats, see our evidence-rated best NAD+ supplements and best NMN supplements roundups, and our hub of vetted NAD+ options.