NAD+: The Definitive Guide

What is NAD+?

NAD+ (nicotinamide adenine dinucleotide) is a helper molecule that cells use to turn food into energy and to run hundreds of other reactions. People inject it, take it through IV drips or swallow it, mostly hoping for more energy, clearer thinking and slower aging. [1], [2], [3]

Chemically, NAD+ is a coenzyme: two nucleotides (small building blocks also found in DNA) joined together, one carrying nicotinamide, a form of vitamin B3, and the other carrying adenine. More than 500 enzymes use it. It is not a peptide, even though it is often sold beside peptides. It passes electrons from one reaction to the next, switching between NAD+ and its partner form, NADH. Enzymes called sirtuins and PARPs also use it up as fuel. [1], [4], [5], [2], [6], [7]

Other names include nadide, coenzyme I, DPN (diphosphopyridine nucleotide) and beta-NAD. NADH, NR (nicotinamide riboside) and NMN (nicotinamide mononucleotide) are related but different compounds, so a study of one does not answer questions about another. [1], [8], [9], [5]

No NAD+ medicine is approved in the United States. Canada has recalled and warned about unauthorized NAD+ injections, and Australia does not allow NAD+ in listed medicines. China registers an injectable form, "coenzyme I for injection", for a few hospital uses. Injections sold elsewhere come from compounding pharmacies, clinics and "research use only" vendors. The human research is small, and most of it tests hospital uses rather than wellness. [9], [10], [11], [12], [13], [14], [15]

Typical NAD+ Protocols

The most common protocol in the reviewed sources is 50 mg per subcutaneous injection, given one to three times a week and often raised toward 100 mg as tolerated. [24], [22], [25], [23] Community education groups most often describe either 20–50 mg once a day or 50–100 mg two or three times a week.

Titration Changing the amount in steps

The usual approach starts low and steps up as the flush and injection reactions allow. One telehealth clinic describes 25 mg one to three times a week for weeks 1–4, then 50 mg for weeks 5–8, then 100 mg from week 9. A compounding pharmacy starts at 20 mg three times a week and adds 20 mg each week, up to 100 mg three times a week. A faster schedule goes from 50 mg to 75 mg to 100 mg daily over three weeks. [25], [26], [16] Some pages instead describe a "loading" period of daily injections: 100–200 mg a day for 7–10 days on one page, which reserves it for supervised settings, or 50–100 mg a day for 1–2 weeks on another. [24], [27]

Breaks and cycles

Sources disagree. One patient sheet describes 3 months on and 1 month off, three times a year; others describe 8–16 weeks of daily injections, or 8–12 weeks, without a fixed break. [23], [16], [27] Community education groups describe both continuous use for many months and cycles of 8–12 weeks on and 4–8 weeks off. No study has compared taking breaks with not taking them.

Read the units: NAD+ doses are in milligrams (mg), about a thousand times larger than the microgram doses of most peptides, and amounts are per injection unless a column says weekly. A 500 mg vial holds 500 mg in total, and syringe units measure volume, so the same 50 mg can be 25, 30 or 50 units depending on how the vial was mixed (worked example). [16], [24], [28]

Low, mid and high are alternatives, not steps to move through, and each row keeps its own amount and duration together. These schedules come from dosing pages and clinic instructions rather than clinical trials; the cited references give the full details, and the study doses below are far smaller or given differently. [3]

Cautions that apply to every row. Reactions such as flushing, chest pressure, a racing heart and near-fainting are reported most often with bigger single doses and fast injections, and community education groups describe a few people who react even to small amounts. No schedule here has been tested in pregnancy, in people under 18 or in people with heart disease. Unit mistakes are common: one pharmacy chart's "50 units" would deliver 100 mg, not 50 mg. "Research use only" vials are not made to the standards required for injectable medicines, and FDA has linked contaminated NAD+ injections to fever-like reactions. [29], [30], [31], [32] When a reaction is an emergency.

What doses are used for IV NAD+?

IV NAD+ is given in clinics as a drip, diluted in a bag of saline (salt water) or glucose solution. The study rows are the complete schedules researchers used; the website rows are what clinics and dosing pages publish.

The IV amounts in the hospital trials were 10–50 mg a day. Clinic drips of 250–1,000 mg are 5 to 100 times larger, and the only published reports of amounts that size are single drips, a four-day series in six people and one person's four fortnightly drips. [15], [33], [34], [35], [29], [36], [41]

What doses have human studies used by other routes?

Where protocols differ: per injection or per week, daily or spaced, loading, breaks and drip speed ↓

What is NAD+ commonly used for?

People who try NAD+ usually describe wanting to feel better in everyday life: more energy, less afternoon slump, clearer thinking, easier workouts or a sense of aging more slowly. Clinics also sell multi-day IV programs for alcohol and drug withdrawal, and NAD+ is often added to weight-loss and "longevity" routines. [40], [48], [23], [3]

The common thread is a simple story: cells need NAD+ to make energy, levels fall with age, so topping them up should help. Each step of that story needs checking. A 2026 review of human and rodent research found no outcome trial of IV or intramuscular NAD+ for anti-aging or wellness, and the sections below separate what was measured from what is claimed. [3]

Energy, fatigue and "anti-aging"

This is the main reason people start. No controlled trial has yet reported whether NAD+ injections improve energy or fatigue in healthy people. A 2026 injection study enrolled adults with mild fatigue, but it reported only how the injections were tolerated; its fatigue results are "to be reported elsewhere." [42]

The closest evidence comes from other routes and related compounds. A 2026 oral NAD+ trial raised blood NAD within six days, but none of its well-being or wearable-device measures held up after correcting for testing many outcomes, and oral NR and NMN raise blood levels without consistent gains in muscle size or function. [44], [51]

People's own reports are split. Some describe steady, "clean" energy; many others notice nothing or feel more tired. The experience section covers both.

Does NAD+ really drop by half as you age?

That claim is common on dosing and pharmacy pages, which say levels fall to about half by middle age or after 50. [25], [17] The research is more mixed, and the answer depends on which tissue is measured and how:

• Brain. A brain-scanning method measured lower NAD+ in older adults, in 17 healthy people aged 21 to 68. [52]
• Skin. Skin removed during surgery from 49 people showed lower NAD+ with age. [6]
• Plasma (the liquid part of blood). One study of people aged 20 to 87 found lower plasma NAD+ with age. [53]
• Whole blood. In 1,518 adults, whole-blood NAD+ averaged 33 micromoles per litre and differed little with age: slightly lower in people in their 40s, about 2 units lower in men aged 60 and over than in men under 30, and no difference in women. A 2026 analysis of seven separate groups, 303 people in all, found whole-blood NAD+ stable with age and with lifestyle programs, while it did rise with NR supplements. [54], [55]

None of these studies supports a fixed figure such as "50% lower by 50." And a lower level in one tissue does not show that injecting NAD+ restores it there, or that restoring it changes health. [55], [3]

Five studies of NAD+ and age: brain, skin and plasma studies show lower levels in older people, while two whole-blood studies show no consistent age decline.

Doserly

Does NAD+ fall with age? It depends on what is measured

Observational human measurements

Lower in older people

Brain

Measured byBrain scan (phosphorus magnetic resonance)People17 healthy adults aged 21–68ResultLower NAD+ in older people

Skin

Measured bySkin removed during surgeryPeople49 people, newborn to 77ResultLower NAD+ with age

Plasmaliquid part of blood

Measured byLaboratory blood testPeopleAdults aged 20–87ResultLower NAD+ with age

No consistent age decline

Whole blood

Measured byLaboratory blood testPeople1,518 adultsResultLittle change with age: slightly lower in the 40s; about 2 µmol/L lower in men 60+ than men under 30; no difference in women

Whole blood

Measured byCarefully checked blood testPeople7 groups, 303 peopleResultStable with age and lifestyle programs; rose with NR supplements

Observational human measurements, not tests of taking NAD+. None supports a “50% by 50” figure.

Brain, skin and plasma levels were lower in older people; two large whole-blood studies found no consistent decline.

Brain fog, focus and mood

Clearer thinking is another common hope. No controlled human trial has tested NAD+ injections for memory, focus or mood. The support comes from animal experiments, such as mice and rats given NAD+ after a stroke or brain injury, which are very different from everyday brain fog. [56], [57], [58] The animal studies are listed in the research library.

Alcohol and drug withdrawal

Doctors described giving NAD+ for addiction as early as 1961, and clinics still sell IV programs for it. That 1961 paper was a "preliminary report" with no available abstract, so its doses and results cannot be checked. A 2024 paper described 50 people who received infusions of NAD+ combined with amino acids and a vitamin mix, with no comparison group, so the effect of NAD+ itself cannot be separated. [59], [60]

No controlled trial of NAD+ for addiction or withdrawal was found. Clinics nevertheless publish programs of 500–1,500 mg a day, given as daily drips for about 3–14 days. [40], [48], [47], [39] Public accounts range from easier early sobriety to no difference and relapse. [61], [62]

Long COVID and chronic fatigue

A 2024 pilot gave 36 people with fatigue after COVID-19 a medicine called low-dose naltrexone plus a weekly NAD+ skin patch. Quality-of-life scores improved over 12 weeks, but there was no comparison group and both treatments were given together, so the patch's share cannot be known. [45] Older trials in chronic fatigue syndrome tested NADH, a different compound, sometimes combined with coenzyme Q10. [63], [64] People with long COVID describe both gains and "crashes" after NAD+. [65], [66]

Heart failure and sudden hearing loss

These are the only uses with randomized trials of NAD+ itself, both in Chinese hospitals, using 5–50 mg a day added to standard treatment. The results were encouraging but small, and the human research section explains them. [15], [33], [14]

Other uses you may come across

• Weight loss. NAD+ is often injected alongside weight-loss drugs such as tirzepatide, and community education groups describe compounded weight-loss injections that include it in the same vial. Reports are mixed, and no study has tested the combination. FDA's April 2026 statement on compounded weight-loss drugs says adding an ingredient such as vitamin B12 to semaglutide may not stop it counting as a copy of an approved drug; it does not mention NAD+. [67], [68], [69]
• Exercise and recovery. Some people describe easier workouts or better endurance, usually while also changing training or taking other compounds. No human trial has tested this. [70], [71]
• Skin and fertility. These claims appear on patient sheets and clinic pages without human studies of NAD+ behind them. [23], [47]

See the human study results or explore the animal research.

Where do NAD+ protocols differ?

The recurring amounts are easier to summarize than the details around them. Sources disagree about how often to inject, whether to build up slowly or "load", how long to continue and how fast to run a drip. Here is what those differences mean when reading a protocol.

Is the number per injection or per week?

50 mg twice a week adds up to 100 mg a week. 100 mg once a day adds up to 700 mg a week, seven times as much. Two schedules that both mention "50 to 100 mg" can differ that much. The table above keeps the amount each time and the weekly total in separate columns so the difference is visible. [23], [16]

Vial sizes add another trap: a "500 mg vial" is the whole vial, not a dose. IV menus quote an amount per session, and the hospital trials gave a daily amount for a set number of days. [16], [41], [15]

Small daily doses or larger doses a few times a week?

Both patterns are common. One chart uses a daily injection; others use one, two or three injections a week; one premixed kit starts with three daily doses, then switches to every other day, with no more than five injections a week. [16], [22], [23], [24], [72] Community education groups describe the same split between small daily doses and larger ones two or three times a week.

No study has compared these patterns. Supporters of daily dosing say the effect fades between spaced injections; supporters of spaced dosing say rest days let them feel it. Because no one has measured how long injected NAD+ stays raised in people, the half-life cannot settle the question.

Start low and build up, or "load"?

The sources describe opposite strategies. Most start at 20–50 mg and step up weekly or every few weeks, as the titration notes above show. [26], [25] A "loading" approach does the reverse: daily injections first, then fewer. One page describes 100–200 mg daily for 7–10 days and says such schedules are typically reserved for supervised settings; another describes 50–100 mg daily for 1–2 weeks. [24], [27]

In community education groups, the stated reason for starting low is to limit the flush and chest pressure that bigger doses bring, not to find an effective dose. The same groups advise starting low again after a break. There is no established rule that feeling nothing at one dose means a higher dose will work.

How long, and are breaks needed?

Course lengths differ from 4 weeks to 16 weeks, and some sources give no end date at all. Breaks range from none to "3 months on, 1 month off." [22], [16], [23], [27] The reasons given for breaks, such as preventing tolerance or keeping the body making its own NAD+, have not been tested for NAD+ injections. What happens when you stop covers the little that is known.

How fast should an IV drip run?

Speed seems to matter, but it has never been tested directly. In the 2019 study, eight men received 750 mg over 6 hours, about 2 mg a minute, and no side effects were observed. In a 2026 review of clinic records, six people each set their own drip speed for 500 mg; the drips averaged 97 minutes, about 5 mg a minute on average, and all six had moderate to severe symptoms that stopped when the drips ended. [34], [29]

A 2024 comparison found that people tolerated a 500 mg NAD+ drip less well than a drip of NR, the precursor, which could run in about a quarter of the time. [35] Clinic instructions describe 250 mg over 2 hours or 500 mg over 4 hours, which is also about 2 mg a minute, and tell staff to slow the drip for first-time users. [38], [26]

These observations mostly point the same way, but they come from different people, settings and ways of recording symptoms, and not every report fits: a 2026 case report describes 250 mg run over about an hour, roughly 4 mg a minute, four times without reported infusion reactions. [36] No study has compared drip speeds, so there is no tested "safe rate." The heart-failure trial gave just 10 mg over 40–60 minutes, and a children's heart trial registered in September 2026 plans to dilute NAD+ to 1.6 mg per mL and run each drip over at least 2 hours. That is a study plan, not a tested limit. [15], [73]

How do milligrams convert to syringe units?

Many people meet "units" on an insulin syringe. A U-100 syringe has 100 units per millilitre, so units measure volume, not an amount of NAD+. How much NAD+ each unit holds depends on how much liquid was added to the vial, a step called reconstitution.

For example, 500 mg mixed into 5 mL gives 100 mg per mL, or 1 mg per unit, so 50 mg is 50 units. The same 500 mg mixed into 3 mL gives about 167 mg per mL, so 50 mg is 30 units. A premixed 200 mg per mL vial holds 2 mg per unit, so 50 mg is 25 units. [24], [16], [28] One pharmacy chart lists 50 mg as 50 units for its 200 mg per mL product, which would actually deliver 100 mg. [30] Doserly's reconstitution calculator works this out for any vial and shows each step.

What happens when you stop NAD+?

This has not been studied. No human study of NAD+ has looked for withdrawal effects or a rebound after stopping. The 2026 injection study's seven-day break was part of its design, not a test of what stopping does. That is an absence of data, not proof that nothing happens. [42], [3]

• How long levels stay raised. In the 6-hour IV study, blood NAD+ was still raised 2 hours after the drip ended; no one measured beyond that. [34]
• What precursor studies show. In a 2026 study of oral NR or NMN, blood NAD took about two weeks to level off and fell back just as slowly after people stopped. That was a different compound taken by mouth. [79]
• The "suppression" worry. Some sources say regular NAD+ makes the body produce less of its own, so breaks are needed. In one 12-week NR trial, an enzyme the body uses to make NAD+ (NAMPT) fell by 14% in muscle while muscle NAD+ stayed the same. No study has tested this with NAD+ injections. [80]
• Community accounts. One account describes the felt effect fading within days of starting. Another person, who had injected 30–40 mg every other day for five months, said their fatigue got worse when they tried to stop; a single account cannot show whether stopping caused it. [81], [82]

The Chinese label describes a 14-day course for its approved uses; the breaks on dosing pages are conventions rather than a response to known withdrawal effects. [13], [23]

Do injected, oral and nasal NAD+ behave the same way?

No. Each route starts somewhere different. An intravenous (IV) drip puts NAD+ straight into a vein. Subcutaneous (into the fatty layer under the skin) and intramuscular (into a muscle) injections have to be absorbed from the tissue first. Oral (swallowed) products meet digestion and the gut wall, nasal sprays meet the lining of the nose, and transdermal patches (absorbed through the skin) meet the skin barrier. A matching amount does not mean a matching exposure.

Six routes of taking NAD+ with what has been measured in people: blood levels for IV drips and one oral product; none published for injections under the skin or into muscle, nasal sprays or patches.

Doserly

What has actually been measured for each way of taking NAD+

Human measurements published for each route

IV dripinto a vein

Human blood measured
750 mg over 6 hours: plasma NAD+ flat for 2 hours, then about 400% above baseline by 6 hours; still raised 2 hours after the drip.

Subcutaneousinto the fatty layer under the skin

Collected, not yet reported
A 2026 study of 100 mg a day for 3 days took blood samples; results are “to be reported elsewhere”.

Intramuscularinto a muscle

Collected, not yet reported
Same 2026 study. China's registered product (5 mg a day) is given this way.

Oralswallowed

Human blood measured (one formulation)
Whole-blood NAD 53% higher than placebo at day 6; plasma NAD unchanged.

Nasal sprayinto the nose

No human data
Animal studies only; the one registered human use combines it with other drugs.

Patchthrough the skin

Not measured
One study used a small electric current with naltrexone; the amount absorbed was not measured.

No human half-life for NAD+ has been published for any route.

Only IV drips and one oral product have human blood measurements; the other routes have none published.

What happens to NAD+ after an injection or drip?

The best measurement comes from the 2019 study of 750 mg given by IV over 6 hours. For the first 2 hours, plasma NAD+ did not rise at all: the authors concluded it was being "rapidly and completely removed" from the blood. Plasma NAD+ then rose about 400% by the end of the drip, along with its breakdown products, and NAD+ was still raised 2 hours later. NAD+ and a methylated breakdown product appeared in urine. The pattern fits enzymes cutting NAD+ apart in the bloodstream. [34]

That fits what cell studies show: NAD+ outside a cell is broken into smaller pieces before cells take them up and rebuild NAD+ inside, as how NAD+ works explains. [7], [83]

Half-life is the time it takes for a level in the blood to fall by half. We found no published half-life for NAD+ given to people by any route, and no human blood measurements after subcutaneous or intramuscular injection. The 2026 injection study collected blood NAD+ samples but has not yet reported them. [34], [42] Half-life figures quoted in community discussions have no published source.

Is oral NAD+ absorbed?

Probably not as intact NAD+, although it can still change blood measurements. In a 2026 randomized trial, a proprietary oral NAD+ powder raised NAD in whole blood (which includes blood cells) by 53% compared with placebo after six days, while NAD in plasma did not change. Breakdown products rose sharply. The paper's own figures conflict on how much NAD+ each dose contained, and the result does not show intact NAD+ passing through the gut. [44]

In mice, swallowed and injected NAD+ both raised nicotinamide breakdown products in urine, a sign that the body broke it down to nicotinamide and cleared the excess. [84] Product quality is a separate problem: when a testing company analysed 10 oral NAD+ supplements, four contained at least 95% of the amount on the label and one had no detectable NAD+ at all. [85]

Oral NR and NMN, which are smaller precursors, raised blood NAD+ in 14 days in a randomized comparison, while nicotinamide did not. Those are different compounds with their own guides: NR and NMN. [5]

Do nasal sprays and patches work?

Nobody has shown that they do in people. We found no published human study of nasal NAD+. The only registered human use we found is a small trial that gives a 30 mg daily NAD+ nasal spray together with low-dose naltrexone, metformin and vitamin B12, so it cannot show what NAD+ does alone. [78] Animal results are mixed: nasal NAD+ protected rats and mice after stroke, brain injury or loss of smell, and helped mice with prion disease, but it did not reduce brain injury after bleeding in the brain in another mouse study. Those were single doses or courses of a few weeks in sick or injured animals, dosed by body weight. [56], [57], [86], [87], [88]

Nasal products are sold at very different strengths, from about 3 mg to 30 mg per spray in the products we reviewed, and people describe both a quick "lift" and stuffy or burning noses. [20], [89], [90], [91], [92]

For patches, the only human study used a patch that pushes the solution into the skin with a small electric current, combined with low-dose naltrexone and without a comparison group. How much NAD+ passed through the skin was not measured, and 11 of 36 people reported skin irritation. [45] Patch products are also sold with directions such as one or two patches a week. [21]

Is subcutaneous or intramuscular better?

That has not been established. The only study comparing routes gave 100 mg for three days to four to six people per route and has not yet published its main pain scores or blood results. [42] The Chinese label uses injection into a muscle. [13] Claims that one route delivers "80%" and the other "100%" circulate in community discussions without any published source. Community education groups report choosing intramuscular injection to avoid the stinging and welts of subcutaneous injections, while others find it more painful.

Does "buffered" NAD+ sting less?

No study has tested it. What is established is that NAD+ dissolved in plain water is acidic: a reagent maker lists a pH of about 3 for a 50 mg per mL solution (pure water is pH 7, and lower numbers are more acidic). [93], [94] Community education groups often say this acidity is why injections sting and that pH-adjusted ("buffered") versions sting less, but that rests on personal reports.

Changing a solution's pH also changes its stability: in laboratory tests, NAD+ breaks down faster in alkaline (high-pH) solutions and at warmer temperatures, and the type of buffer made a large difference. [95], [93] Those were laboratory solutions, not injectable products, which is why product-specific stability data matter.

How should NAD+ be stored, and how long does it last?

No one has published a stability study of the vials people mix at home, so most storage advice comes from product instructions rather than tested data.

• Powder, before mixing. The Chinese registered product says to protect the freeze-dried powder from light and keep it sealed in a cool place no warmer than 20 °C, with a 24-month shelf life. A research-vial dosing page says to keep powder frozen at −20 °C, while a telehealth clinic's instructions say to store it at room temperature (20–25 °C), away from heat, moisture and light. [13], [16], [25]
• After mixing, or premixed liquid. A compounding pharmacy says its premixed NAD+ must stay refrigerated at 2–8 °C, protected from light and never frozen, with a use-by date usually about 90 days from preparation and disposal about 28 days after the vial is first punctured. A premixed kit allows up to 30 days below 25 °C but recommends the fridge. Research-vial pages say to refrigerate after mixing, protect from light and avoid repeated freezing and thawing; one says to use the vial within 30 days. [17], [72], [16], [22]
• What lab-grade solutions show. A reagent maker reports that NAD+ dissolved in water at 10 mg per mL kept more than 99% of its NAD+ after 8 weeks at 2–8 °C. A stronger 50 mg per mL solution kept 91% after 10 days at 2–8 °C, but only about 83% after 10 days at 33 °C. [93] These figures describe laboratory reagents; they say nothing about sterility, and they do not tell you how long a particular injectable product lasts.
• Colour. Sources conflict. One research-vial page says to discard a solution that is discoloured; a premixed kit's instructions say its liquid is "sometimes yellow-tinted." [16], [72]
• Sterility. FDA has warned that food-grade NAD+ used to make IV products carries a high risk of contamination with microbes and endotoxins (fever-causing bacterial toxins). Storage cannot fix a product that was not sterile to begin with. [31]

The durations above are manufacturer and vendor claims, not tested expiry dates for every product. This guide does not cover mixing or injection technique; the Academy note below covers practical handling.

What do we actually know about NAD+ in people?

The human studies of NAD+ itself are small, and they ask different questions: how the body handles an IV drip, how well people tolerate different routes, and whether small hospital doses help in heart failure or hearing loss. None tested whether NAD+ slows aging or raises energy in healthy people. [3]

Feeling better after a treatment is real to the person experiencing it. Working out why is a separate task, because symptoms change over time, other treatments help, and expectations affect how people feel. Controlled trials help separate those effects from the treatment itself.

What did the human studies find?

These are about a dozen small studies and reports from different teams, using different doses and routes. Several were funded by, or written by people linked to, companies that sell NAD+ or a competing product, including the maker of the Chinese NAD+ product, which funded the heart-failure and hearing trials. [34], [35], [42], [29], [44], [15], [33], [14]

What did the heart-failure trials show?

The strongest study is the 2025 Chinese trial in people with heart failure caused by narrowed heart arteries. A week of 10 mg a day on top of their usual medicines left their hearts pumping slightly better at one month. Fewer people in the NAD+ group had a serious heart event or hospital stay over six months, but that difference could have been chance. A smaller trial in older adults using 50 mg a day found improvements that were not statistically significant. [15], [33]

Both used a registered hospital product, given into a vein although its label describes 5 mg injected into a muscle, at doses far below wellness drips. [13] They cannot show that a 500 mg drip, or a weekly injection, helps a healthy heart.

Is there proof that NAD+ slows aging?

No. A 2026 review of 33 human and 80 rodent studies found no outcome trial of IV or intramuscular NAD+ for anti-aging or wellness. [3] Two other 2026 reviews agree: one concludes that IV "longevity" drips, NAD+ among them, should be regarded as experimental, and the other says IV NAD+ is less well characterized than the oral precursors and lacks robust clinical validation. [96], [97] The same year, researchers using a carefully checked blood test concluded that whole-blood NAD+ does not work as a marker of aging, because it stayed stable across ages. [55] Raising a blood number and changing how a person ages are different things, and only the first has been measured.

Do NR and NMN studies tell us about NAD+?

They tell us about NR and NMN. These oral precursors are smaller molecules that the body converts into NAD+, and they have many more human trials:

• Blood levels rise. Single doses of 100–1,000 mg of NR raised NAD-related molecules in blood; six weeks of NR raised NAD+ in middle-aged and older adults; NMN at 300–900 mg a day for 60 days raised blood NAD. [49], [98], [99]
• Brain levels can rise. In a 30-person trial in newly diagnosed Parkinson's disease, 1,000 mg of NR a day for 30 days raised brain NAD in those taking it, by varying amounts. [100]
• Very high doses raise levels further. In a four-week safety trial in 20 people with Parkinson's disease, 3,000 mg of NR a day raised blood NAD+ up to fivefold. Blood glutathione did not change, and the body's supply of methyl groups stayed intact. [101]
• Outcomes are inconsistent. Twelve weeks of NR at 2,000 mg a day did not change muscle mitochondria in men with obesity, and a 2025 review found no consistent effect of NR or NMN on muscle size or strength. [80], [51]

None of these used injected NAD+. Their milligram amounts cannot be copied into an NAD+ vial chart. [49], [51]

What would a useful improvement look like?

"More energy" can mean many things: getting through the afternoon without a nap, training harder, sleeping better or thinking more clearly at work. Those are different outcomes, and a change in one does not answer questions about the others. The more helpful accounts say what the person could do before and after, what else changed, and whether the effect lasted beyond the first week. [102], [103]

How does NAD+ work, and what might extra NAD+ do?

What NAD+ does inside cells is well established. What an injection or drip adds to that is not. This section keeps the two apart.

What does NAD+ do inside cells?

• Carries electrons. NAD+ picks up electrons in reactions that break down food, becoming NADH, and hands them on to make energy. [1]
• Fuels repair and signalling enzymes. DNA-repair enzymes called PARPs and the sirtuins, which switch genes and proteins on and off, use NAD+ up as they work. [6]
• Gets broken down and recycled. An enzyme on cell surfaces called CD38 is a major NAD+-consuming enzyme in mammals. Cells rebuild NAD+ from vitamin B3 forms such as nicotinamide and from precursors like NR and NMN. [104], [7], [5]

In a small skin study, older age in men went along with more PARP activity and lower NAD+, which the researchers have suggested may link DNA damage to NAD+ loss with age. That is an association in tissue samples, not evidence that taking NAD+ reverses it. [6]

Can injected NAD+ get into cells?

Not in one piece, as far as the evidence goes. In studies of human cells grown in a dish, NAD+ outside a cell was cut into smaller pieces, such as nicotinamide and NR, which cells took up and rebuilt into NAD+. [7], [83] A separate transporter moves intact NAD+ into mitochondria (the cell's energy-producing compartments), but that happens inside the cell, not from the blood. [105] The 6-hour IV study found the same enzyme fingerprints in blood. [34] So an injection may work largely as a supply of building blocks, much like the oral precursors, but that has not been measured directly in people.

What happens to the nicotinamide part?

The body clears extra nicotinamide by attaching a methyl group to it, using an enzyme called NNMT and a methyl donor called SAM. [106] After NAD+ drips and oral NAD+, these methylated breakdown products rose in urine and blood. [34], [44]

Two points follow. First, community education groups often say NAD+ "drains" methyl groups and recommend methyl donors such as TMG (trimethylglycine) or methylated B vitamins; no study has tested whether NAD+ injections deplete methyl groups in people or whether those supplements change how people feel. Second, two end products of this breakdown (called 2PY and 4PY) were linked with a higher three-year risk of heart attack, stroke or death in large observational studies of heart patients; high levels likely reflect excess niacin. That link has not been studied for NAD+ injections, and it cannot be turned into a risk figure. [107]

Why might injections cause flushing, chest pressure or tiredness?

Nobody knows. The flushing caused by niacin (nicotinic acid) runs through a specific receptor, shown in mice, but that pathway has not been shown for NAD+. [108] In mice, NAD+ outside cells acts as a danger signal on some immune cells: injected into a vein, it rapidly killed certain T cells (a type of white blood cell). [109], [110] The authors of the 2026 injection study suggest a similar immune signal might explain IV side effects, but that is a hypothesis. [42] Separately, the 2024 comparison study reported a rise in white blood cells after an NAD+ drip. [35]

Does the time of day matter?

NAD+ levels and the enzyme that recycles it naturally rise and fall over the day in mouse tissues and cells, as part of the body clock. [111], [112] In obese mice, NAD+ given before their active period improved weight, blood sugar and liver measures, while the same dose given before their rest period weakened those effects and shifted the liver's daily clock. That has not been tested in people, so it does not establish a best time to inject. [113]

Can apigenin or other "CD38 blockers" raise NAD+?

Apigenin, a plant compound from the flavonoid family, blocked CD38 in cells in a 2013 study; injected into the abdomen of obese mice at 100 mg per kg daily for a week, it raised NAD+ in their livers. [104] A later study found that apigenin raised the ratio of NAD+ to NADH in the kidneys of diabetic rats. [114] We found no human trial measuring whether apigenin or the related compound quercetin raises NAD+ in people. Community education groups nevertheless include apigenin in NAD+ routines.

What are the risks and unanswered questions?

Is NAD+ safe?

Its safety for repeated wellness use has not been established. The small studies found few problems with slow drips and small hospital doses, but frequent, uncomfortable reactions with faster, larger drips. Nobody has studied months of weekly or daily injections.

The reassuring results come with limits. A slow 6-hour drip caused no observed adverse events in eight men; the 10 mg heart-failure trial reported one case of brief dizziness; the hearing-loss trial reported no adverse events in its NAD+ group. [34], [15], [14] Small, short studies can miss uncommon or slow-developing problems, so "no problems seen in eight people" is not the same as "safe for months of injections."

What side effects have been reported?

• During IV drips: cramps, diarrhea, nausea, vomiting, a faster heart rate, throat pain, congestion and chest pressure in all six clients given 500 mg drips, stopping when the drips ended; the 2024 comparison also found NAD+ drips harder to tolerate than NR drips. [29], [35]
• On the Chinese label: occasional dry mouth, nausea, dizziness and palpitations. [13], [33]
• Blood tests: a rise in white blood cells after one drip, and a small fall in HDL ("good") cholesterol over 30 days; neither has been followed up. [35], [29]
• Skin: irritation in 11 of 36 people using a patch; in the injection route study nobody dropped out because of discomfort, but symptoms were recorded only as free-text comments. [45], [42]
• After repeated injections: in a small Japanese study of three 200 mg subcutaneous injections two weeks apart, 20 people reported 17 mild or moderate side effects, none serious; the public summary does not say what they were. [43]
• Contaminated products: reports to FDA of severe chills, shaking, vomiting and fatigue after NAD+ injections, some needing medical treatment, which FDA said were consistent with excessive levels of endotoxins. [31]
• In animal safety testing: in a 2026 laboratory safety study of injections into a muscle, rats given daily doses for four weeks had injection-site and nearby nerve damage that healed after stopping, and dogs given single larger doses had a faster heart rate and lower blood pressure. Only the summary of that study could be reviewed. [115]

Public accounts add stinging, welts, flushing, near-fainting and unexpected tiredness. The community section describes them.

When is a reaction an emergency?

The same rules apply whatever the cause. MedlinePlus, the US National Library of Medicine's health site, advises calling 911 or your local emergency number for sudden crushing, squeezing, tightening or pressure in the chest, for chest pain with nausea, dizziness, sweating, a racing heart or shortness of breath, and for breathing difficulty that comes on suddenly or makes it hard to talk. [116], [117] After a faint, it advises emergency help if the person does not become alert within a couple of minutes, fell from a height (especially if injured or bleeding), is pregnant, is over 50, has diabetes, feels chest pain or pressure, or has a pounding or irregular heartbeat, among other signs. [118] During a clinic drip, symptoms in the studies stopped once the drip stopped, so staff need to know about chest pressure or faintness straight away. [29]

Could product quality or the IV procedure change the risk?

Yes. The chemical itself and the quality of a particular product are separate questions.

• Food-grade ingredients. In October 2024, FDA reminded pharmacies that some were making IV NAD+ from food-grade powder sold by repackagers. Food-grade ingredients are not suitable for sterile injections without appropriate processing and carry a high risk of contamination with microbes and endotoxins. [31]
• A contaminated vial. In a January 2026 warning letter, FDA described three patients who developed low blood pressure, uncontrollable shaking, shivers and body aches after NAD+ from the same vial and were sent to an emergency room. An unopened vial from the same batch contained 3,360 endotoxin units per mL. The company recalled its sterile products in July 2025. [32]
• Unauthorized products. Health Canada recalled compounded NAD+ drips sold without authorization in 2025, and in 2026 warned that such injectables have not been assessed for safety, effectiveness or quality. [10], [11]
• The IV procedure itself. In July 2026, a 27-year-old woman died after losing consciousness during an NAD+ drip at a New York wellness center. News reports say the city's medical examiner found the cause was air introduced into her IV line by an unlicensed practitioner. That was a failure of the procedure, not a known effect of NAD+, and it shows why who gives an IV matters. [119]

Is NAD+ legal? Is it FDA-approved?

Checked September 24, 2026. Rules differ by country and change quickly.

United States. No NAD+ drug is FDA-approved. [9], [32] The steps so far:

• September 2019. FDA proposed not to add NAD (or NADH) to the list of bulk ingredients that pharmacies may use for compounding. The proposal has not been finalized. [9]
• October 2024. FDA warned pharmacies about food-grade NAD+ in IV products. [31]
• January 2026. A warning letter stated that NAD+ is not on the list of ingredients that larger "outsourcing" compounders may use and that the firm's NAD+ injections were unapproved drugs. [32]
• May 2026. FDA's updated list still places NAD in the "under evaluation" group for pharmacy compounding. That is not an approval. [9]

Oral NAD+ products are sold as dietary supplements, which FDA does not approve before sale. FDA's list of new-supplement-ingredient notifications includes NMN and NR entries in 2025–2026 but no NAD+ or NADH entry. [120]

Canada. In September 2025 Health Canada recalled compounded products including an NAD+ IV drip solution that had no market authorization. Its April 2026 advisory lists NAD+ among unauthorized injectables to avoid and says unauthorized drug products "are illegal in Canada." [10], [11]

Australia. The Therapeutic Goods Administration says NAD, NAD+ and NADH are not permitted ingredients in listed medicines (its alert was first published in April 2025 and updated in February 2026). One register entry exists for an under-the-tongue NAD+ product; the public record does not explain its licence category, so it should not be read as permission to sell NAD+ products generally in Australia. [12], [121]

China. Coenzyme I for injection is a registered medicine, used in the hearing-loss and heart-failure trials; a transcribed copy of its label lists add-on treatment of low white-blood-cell counts, and treatment of coronary heart disease and myocarditis. [14], [15], [13]

A "research use only" label does not make an injectable product legal to sell or safe to use. [11]

Is NAD+ banned in sport?

NAD+ itself is not named on the World Anti-Doping Agency's 2026 Prohibited List. The method matters, though: IV infusions or injections of more than 100 mL in total within 12 hours are prohibited at all times, except during hospital treatment, surgery or clinical tests. [122] USADA explains that this applies even when the substance infused is permitted, and that an athlete may need a Therapeutic Use Exemption. A 500 mL wellness drip, like those in the clinic study, is five times the limit. [123], [29]

Does NAD+ cause cancer?

Nobody knows; there are no human data either way. The animal and cell signals point in different directions and mostly involve related compounds:

• A 2019 study in cells and mice found that the cell's NAD+-making machinery drives inflammatory signals released by aging cells, signals that can help tumours grow; the authors urged that NAD+-raising supplements be used "with precision." [124]
• In a mouse model of aggressive breast cancer, NR supplements increased cancer and its spread to the brain. [125]
• In a 1972 mouse study, repeated NAD injections slowed tumour-cell growth. [126]
• In lab dishes, extra NAD+ or NMN let tumour cells survive a drug designed to starve them of NAD+. [83]

These are different compounds, species and cancers. They justify caution for people with cancer, not a risk estimate.

Does NAD+ affect heart rate or blood pressure?

Heart rate: yes, at least during drips. A faster heart rate was one of the symptoms all six clinic clients reported during 500 mg drips, and the Chinese label lists occasional palpitations. [29], [13]

Blood pressure: a signal in animals, not measured as a drop in people. The same six clients' measured blood pressure did not change significantly over four days of drips. [29] In the 2026 animal safety study, single injections of 10 and 30 mg per kg into a muscle lowered blood pressure and raised heart rate in dogs, while 3 mg per kg did not; the full results were not available to review. [115] We found no published report of NAD+ causing low blood pressure or fainting in a person. The contaminated-vial patients did have low blood pressure, which fits endotoxin exposure rather than NAD+ itself. [32], [31]

Some people describe low blood pressure or heart-rate changes after injections, and community education groups include a few accounts of pressure dropping on NAD+. [127], [128] Single accounts cannot sort out the cause. Extra care for people with low blood pressure or on blood pressure medicines is a reasonable inference from these signals, not a tested finding.

Who should be especially cautious?

These groups have little or no safety data. That is a reason for caution, not proof of harm.

• Pregnancy and breastfeeding. The Chinese label says use in pregnancy and breastfeeding has not been tested. [13]
• Heart disease. The heart-failure trials used 10–50 mg in hospital. Large wellness drips have not been studied in people with heart disease, and they can cause chest pressure and a fast heart rate. [15], [33], [29]
• Low blood pressure or blood pressure medicines. Because of the animal blood-pressure signal and personal reports above; not studied in people. [115]
• Kidney or liver disease. The main heart-failure trial excluded people with severe liver or kidney problems, so there are no data for them. [15]
• A history of cancer. Because of the unresolved animal findings above. [124], [125]
• Under 18. The label says children have not been tested, and this guide is written for adults. [13]
• Competitive athletes. Because of the IV volume rule. [122]
• People taking other medicines. See the next question.

Has NAD+ been tested alongside other medicines?

Not properly. The Chinese label says interactions have not been tested. The trials gave NAD+ alongside standard heart medicines or steroids without reporting interaction problems, but they were not designed to find them. [13], [15], [14] Community education groups field frequent questions about combining NAD+ with blood pressure medicines, antidepressants, diabetes drugs, weight-loss injections and cancer treatments; none of these combinations has been studied. Warnings you may see about raised blood sugar and liver injury come from labels for niacin (nicotinic acid), a different form of vitamin B3; we found no evidence that NAD+ itself raises blood sugar. [129] Bring a complete list of everything you take to a pharmacist or doctor.

What should be monitored while using NAD+?

There is no official monitoring plan for wellness use, because no regulator has approved NAD+ for it, and the Chinese label lists no monitoring tests. What exists is a record of what the small studies measured. It can help you prepare questions for a clinician; it is not a personal testing plan. [13], [3]

What did the human studies check?

• The 6-hour IV study tracked NAD+ and its breakdown products in blood and urine, and liver tests (bilirubin, alkaline phosphatase, ALT, GGT, LD and AST), with observation for side effects. [34]
• The clinic records included blood pressure, resting heart rate, liver enzymes (ALT and AST), C-reactive protein (a marker of inflammation), kidney tests, thyroid-stimulating hormone, and, as extras, blood sugar measures and cholesterol. [29]
• The injection route study checked vital signs (blood pressure, heart rate, breathing rate, oxygen level and temperature), blood sugar, insulin and inflammation markers, after each injection. [42]
• The 2024 comparison reported blood cell counts, including the white-cell rise. [35]
• The heart-failure trial measured heart pumping, a heart-strain blood test (NT-proBNP) and liver, kidney and blood sugar tests. [15]
• The oral trial measured NAD in whole blood and plasma separately, with vital signs and wearable-device data. [44]

Which signals matter, and why?

Do home NAD+ blood tests tell you much?

Not yet. Results depend on what is measured: the oral trial raised NAD in whole blood but not in plasma. [44] NAD+ in plasma is about 500 times lower than inside white blood cells, and the way a sample is spun and handled can change the reading; researchers who developed a reference laboratory method note that these molecules are unstable while blood is being collected. [2], [130] We found no validated clinical reference range for home NAD+ tests. Because whole-blood NAD+ stayed stable across ages in a carefully checked 2026 study, there is no established "optimal" level to aim for, although community education groups circulate one. [55]

What do people in public communities report?

Public discussions include steady energy, no change at all, and reactions frightening enough that people stopped. The most useful accounts explain what else was going on and come back with an update. Most were also taking something else, most often MOTS-c, SS-31, weight-loss drugs or supplements. [131], [132], [133]

What do the positive reports look like?

One person who added NAD+ to other compounds they were already taking started at 25 mg every other day, moved to daily, and said a month later that they no longer needed afternoon naps and could focus better. Another said their focused work sessions stretched from about 45 minutes to over 90 after four months. [134], [135] A person with long COVID said about 30 mg a day seemed to help their energy "quite a lot," alongside many other treatments over nearly six years. [66]

Some IV accounts are striking. One person with Ménière's disease (an inner-ear disorder) said their vertigo was gone the morning after a first 500 mg drip, which ran over 5 hours and felt "HORRIBLE" throughout; a later 1,000 mg drip was so intense they stopped it after 6 hours. [136] Such stories are real experiences, but they cannot separate NAD+ from time, other treatments and expectation.

How long did those changes last?

Often not long, and follow-ups change the picture. One person felt alert for two days after a first 25 mg injection, noticed nothing after the second and felt tired and unfocused after the third. Another felt excellent for two weeks, then developed fatigue and brain fog, though they had also increased another compound. [81], [137] One long-term user described about 36 hours of benefit after each weekly 100 mg drip, over two years. [138]

The accounts cannot provide an average time to benefit. The people posting are not a representative sample of everyone who has tried NAD+.

Does everyone notice something?

No. Nonresponse is one of the most common themes. People describe 25–50 mg three times a week with no effect, 50 mg daily for eight weeks with nothing, 20 IV drips of 1,000 mg with no benefit, and titrating up to 100 mg before giving up on "painful injections." [139], [138], [140] Community education groups report the same, and offer explanations such as not being deficient or needing another compound first. None of those explanations has been tested.

What are the rushes, chest pressure and near-fainting people describe?

These are the most common serious-sounding reports. One person felt light-headed with chest tightness within minutes of pushing a 50 mg injection faster than usual; it passed in about ten minutes. [141] Another had two episodes of nearly fainting within about 30 seconds of routine injections; a clinician suspected a fainting reflex. [142] Others describe sudden light-headedness, nausea and palpitations, or tingling, numbness and "extreme chest tightness." [143], [144] IV users describe chest pressure, burning and breathlessness when drips ran fast. [145], [146]

Community education groups describe the same pattern, including a few actual faints: reactions seem worse with bigger single doses, faster pushes and more concentrated solutions, and a few people react even at 5–25 mg. This matches what the clinic study recorded for drips, but nobody has studied it for injections. The emergency guidance above applies. [29]

Why do some people feel tired instead of energized?

This paradox comes up again and again. People describe months of lethargy, being "very, very tired" at 50 mg twice a week, sleeping 12 hours a night after 100 mg, or NAD+ making fatigue from a weight-loss drug worse. [147], [148], [149] A few describe fever or shaking chills after drips; one had a temperature of 39.6 °C an hour after a high-dose IV; another later linked their shivering to a series of chiropractor appointments. [150], [146] From single accounts it is impossible to tell whether such reactions came from NAD+, the product's quality or something else. [31]

What about stinging, lumps and welts?

Injection-site trouble is very common. Accounts describe burning at 100 mg in 1 mL, bruising after every injection, and hard lumps that lasted about four weeks. [151], [152], [153] Community education groups describe large, itchy welts appearing a day later, with the thigh often worst. People report that more dilution, slower injection, pH-adjusted products and rotating sites helped them, but none of these has been tested.

Does getting worse mean it is working?

The evidence does not support that. Some community education material describes chest pressure, tiredness or big reactions as signs of "repair" or of cells "adjusting." No study supports this, and chest pressure, breathlessness or fainting deserve attention in their own right. A disappointing response also does not prove the dose was too low.

How can you judge an NAD+ story?

Useful questions to ask: Exactly what product, amount, route and concentration were used? What else was being taken or changed at the same time? What did the person feel before starting? Did the effect last past the first week? Follow-ups matter: one person who blamed an NAD+ drip for a sore throat and swollen glands later reported that it had been strep throat. [154]

These selected discussions help identify questions and experiences worth studying. They are not a survey of all users, a response rate or a substitute for controlled studies.

How does NAD+ compare with NR, NMN and NADH?

These are the compounds most often confused with NAD+, and people often switch between them. The table compares what each is and how much human evidence exists; the route column describes what studies and sellers use, not recommended doses.

The real differences are in chemistry, route and evidence, not in proven results. NR and NMN are swallowed and have far more human trials, while NAD+ is mostly injected and has only a handful. No study has compared NAD+ injections with oral NR or NMN for any health outcome. Doserly's NAD+ precursors guide covers the oral options in more depth. [5], [51], [3]

Common questions about NAD+

Is NAD+ a peptide?

No. NAD+ is a coenzyme made of two nucleotides, not a chain of amino acids, even though it is often sold alongside peptides and one Canadian advisory lists it under "peptides." [1], [11] See What is NAD+?

How long does NAD+ take to work?

There is no established timeline, because no controlled trial has reported energy or well-being results for NAD+ injections. Community accounts range from a rush within minutes to changes after weeks, to nothing at all. [71], [134], [139] In the trials, the oral powder raised blood NAD within six days, and the heart-failure trial measured heart pumping after one month. Those are blood and heart measurements, not how people felt. [44], [15] See how long changes lasted.

Is NAD+ the same as NMN, NR or NADH?

No. NR and NMN are smaller precursors the body turns into NAD+, and NADH is its partner form after it carries electrons. Each has its own studies and doses, and results for one cannot be transferred to another. [5], [1] See the comparison table.

Can you take NAD+ as a pill or nasal spray?

Both are sold, but neither has shown intact NAD+ reaching the bloodstream. An oral powder raised NAD in whole blood without changing plasma NAD, and we found no human study of nasal NAD+. Testing has also found oral products with far less NAD+ than their labels state. [44], [85] See why the route matters.

Is an IV drip better than an injection?

That has not been shown. IV drips deliver larger amounts quickly and caused frequent symptoms when run fast, while subcutaneous injections deliver smaller amounts and no human study has measured their blood levels. No study has compared the two for any benefit. [29], [34], [42] See how fast a drip should run.

Can NAD+ help with addiction or withdrawal?

It has not been shown to. No controlled trial of NAD+ for addiction or withdrawal was found; the evidence is a 1961 preliminary report and a 2024 series of 50 people given NAD+ combined with other nutrients. Clinics still sell multi-day programs. [59], [60], [40] See alcohol and drug withdrawal.

What is an NAD+ stack with MOTS-c, SS-31, 5-Amino-1MQ or glutathione?

It means injecting NAD+ alongside other research compounds said to support mitochondria (the cell's energy-producing compartments), most often MOTS-c, SS-31 or 5-Amino-1MQ. These combinations are common in community discussions, but no study has tested any of them together with NAD+, and stacking makes it impossible to tell which compound caused an effect. [140], [132], [131] A common worry is that NAD+ and glutathione "cancel out." No study has tested the two together, but in a trial of very high-dose oral NR that raised blood NAD+ up to fivefold, blood glutathione did not change. [101]

Is it legal to buy NAD+?

It depends on the product and the country. Oral supplements are widely sold, while NAD+ injections are not FDA-approved, have been recalled as unauthorized in Canada, and are not permitted in listed medicines in Australia. [32], [10], [12] See the dated legal summary.

Glossary

Plain explanations of the route, dosing and research terms used in this guide. Underlined terms in the text link here.

Adverse event

A harmful or unwanted medical event reported after someone used a treatment. A report alone does not prove the treatment caused it.

Animal study

Research in animals such as rats or mice. It shows what a substance does in a living body, but results in people can differ, and animal doses by body weight do not translate directly to people.

Bioavailability

How much of a dose reaches the bloodstream in a usable form. It depends heavily on the route and has not been measured for NAD+ injections in people.

CD38

An enzyme on the surface of many cells that breaks down NAD+. It is a major NAD+-consuming enzyme in mammals.

Cell study (in vitro)

Research on cells grown in a dish. It gives early clues about biology, but it is far from proof of benefit in people.

Coenzyme

A small helper molecule that an enzyme needs to do its job. NAD+ is a coenzyme for many enzymes that handle energy and repair.

Compounding

When a pharmacy prepares a customized medicine from individual ingredients. In the US, federal lists control which bulk ingredients pharmacies may use, and compounded products are not FDA-approved.

Controlled trial

A study that compares people who receive a treatment with a similar group who do not, often receiving a placebo instead. Randomly assigning people to each group makes the comparison fairer.

Course and cycle

A course is the period of repeated use, such as eight weeks. A cycle is a course plus a planned break before any further use.

Daily and weekly total

All the amounts given in a day or a week, added together. For example, 50 mg twice a week is a 100 mg weekly total.

Dose (amount each time)

The amount given on one occasion. A protocol lists both the dose and how often it is given.

Ejection fraction

The share of blood the heart's main pumping chamber pushes out with each beat. It is a standard measure of how well the heart pumps in heart failure.

Endotoxin

A toxic substance from the outer layer of certain bacteria. In an injection it can cause fever, chills, shaking and low blood pressure, even if no live bacteria are present.

Freeze-dried (lyophilized)

Dried by freezing and removing the water, leaving a powder. Many NAD+ vials are sold this way and mixed with liquid before injection.

Half-life

The time it takes for the measured level of a substance in the blood to fall by half. It is not the same as how long an effect lasts, and it has not been published for injected NAD+.

Intramuscular (IM)

Injected into a muscle.

Intravenous (IV)

Given directly into a vein, as a quick push from a syringe or as a slower drip, so it enters the bloodstream immediately.

Investigational

Still being studied and not approved by a regulator, such as the FDA, for the use in question.

Loading phase

Starting with a higher or more frequent amount for a short period, then lowering it.

mg and mcg

Milligrams and micrograms. 1 mg equals 1,000 mcg. NAD+ amounts are written in mg, much larger than the mcg amounts used for most peptides.

NADH

The form NAD+ takes after it picks up electrons. Cells switch between the two constantly. NADH is also sold as a separate supplement with its own research.

NMN (nicotinamide mononucleotide)

A precursor that cells turn into NAD+ in one step. It is usually taken by mouth and has its own trials.

NR (nicotinamide riboside)

A form of vitamin B3 that the body turns into NAD+. It is usually taken by mouth and has more human trials than NAD+ itself.

Oral

Taken by mouth, as a capsule, tablet, powder or liquid.

PARP

Poly(ADP-ribose) polymerase: a family of DNA-repair enzymes that use up NAD+ as they work.

Peptide

A short chain of amino acids, the building blocks of proteins. NAD+ is not a peptide.

Pharmacokinetics

How the body absorbs, moves, breaks down and removes a substance.

Placebo

A dummy treatment with no active ingredient, used as a comparison in studies.

Preclinical research

Studies done before research in people: cell studies and animal studies.

Precursor

A building block the body converts into something else. NR, NMN and nicotinamide are precursors of NAD+.

Preprint

A research paper posted publicly before other scientists have formally reviewed it. Its findings may change before publication.

Reconstitution

Mixing a freeze-dried powder with a liquid so it can be measured and injected. The amount of liquid sets how much NAD+ each unit holds.

Research use only

A label on products sold for laboratory research. It does not mean a product is approved, tested for human use or legal to sell as a medicine.

Sirtuins

A family of enzymes that switch other proteins and genes on or off and use up NAD+ to do it. They are studied in aging research.

Subcutaneous (SC)

Injected into the fatty layer just under the skin. This is the route most NAD+ dosing pages describe.

Syringe units

Markings on an insulin syringe that measure volume. On a U-100 syringe, 100 units equal 1 mL. The amount of NAD+ per unit depends on the vial's concentration.

Titration

Adjusting a dose in steps, usually starting lower and increasing if tolerated.

Transdermal

Absorbed through the skin, for example from a patch.

WADA

The World Anti-Doping Agency, which publishes the list of substances and methods banned in sport.

Withdrawal and rebound

Withdrawal effects are symptoms caused by stopping a substance. A rebound is a problem returning worse than before after stopping. Neither has been studied for NAD+.

Explore more of the research

These studies gave NAD+ itself to animals or cells. They explain why researchers are interested, but each used a specific injury model and a dose by body weight that cannot be converted into a human protocol.

How this guide was researched

This guide is built from a thorough review of the sources cited throughout it: published scientific studies, registered clinical-trial plans, regulatory documents and published protocol descriptions. We also reviewed public online forums and community education groups where people describe their own experiences with NAD+.

The guide cites 173 sources, including 73 original scientific papers and preprints. Each type of source answers a different question. Studies show what researchers measured. Protocol descriptions show how NAD+ is typically used. Personal accounts show what individual people experienced. Every numbered citation links to its entry below, labeled by source type.

How this guide was made

Research and drafting were AI-assisted. Every cited source was checked against the original, and the guide was reviewed and edited by Doserly before publication. It has not had an independent clinical review, and Doserly does not currently have medical reviewers. Doserly makes a medication and health-tracking app and runs Doserly Academy, both of which are promoted in this guide. Read our editorial policy for how guides are researched, updated and corrected.

This guide is for educational purposes. It summarizes what the reviewed sources report so the research is easier to understand; it is not medical advice. For a deeper dive, or to check any point for yourself, go straight to the cited sources.

Explore the sources