Energy & Endurance

NAD+

Evidence

What is NAD+?

NAD+ (nicotinamide adenine dinucleotide) is a naturally occurring dinucleotide coenzyme found in almost every cell in the body. It is essential for normal cellular metabolism. One of its most important jobs is helping the body turn nutrients (carbohydrates, fats and amino acids) into usable cellular energy.

It also plays a role in redox chemistry, DNA repair, cellular stress responses, sirtuin activity and other NAD-dependent enzymes. NAD+ is part of the NAD+/NADH redox system. It is not a peptide, a hormone, a stimulant or a GLP-1 agonist.

How well studied is it?

NAD+ biology is extremely well understood; NAD+ injections are much less studied. Scientists know a great deal about what NAD+ does inside cells, NAD+/NADH chemistry, how the body makes and recycles NAD+, the enzymes that use it, and NAD+ precursors such as NR and NMN. That does not mean injecting NAD+ has equally strong clinical evidence.

Direct NAD+ administration has mainly been studied through small IV studies, short human metabolism studies, early tolerability research, and very small preliminary IM and SC exposure studies. A 2026 preliminary safety analysis reported small human groups receiving 100 mg NAD+ by IM, SC or IV-push on 3 consecutive days. This gives early controlled human exposure through IM and SC routes, but does not show that those doses provide clinical benefits.

The body tightly controls NAD+ production, recycling, breakdown, transport and intracellular levels, and NAD+ outside cells is heavily metabolized. The open question is whether injecting extra NAD+ improves meaningful health outcomes in people. For most wellness claims, that is still unknown.

Evidence level

Overall evidence rating: extremely strong biology, limited direct-injection evidence

• Strong evidence for: NAD+/NADH chemistry, cellular energy metabolism, NAD-dependent enzymes, direct IV NAD+ metabolism, and route-dependent tolerability.
• Early human evidence for: short-term exposure to 100 mg NAD+ by IM, SC and IV-push.
• Limited or unproven for: anti-aging, longevity, fatigue treatment, athletic enhancement, fat loss, cognition, hangovers, alcohol detoxification, GLP-1 fatigue, long-term 50–200 mg IM protocols, daily 50–100 mg SC protocols, and loading or maintenance cycles.

Primary research focus

• Best established: cellular energy metabolism, redox reactions, NAD-dependent enzyme biology, cellular metabolism.
• Direct human administration research: IV metabolism, IV tolerability, early IM / SC tolerability.
• Common wellness claims not established: energy enhancement, anti-aging, cognitive enhancement, fatigue treatment, addiction detoxification, weight loss, athletic performance.

What may it help with?

Strong biological evidence

• Cellular energy metabolism: NAD+ is required for normal energy metabolism. Being necessary for energy production does not mean injecting more NAD+ gives a healthy person more energy; those are two different claims.
• Redox balance: NAD+ accepts electrons and becomes NADH; NADH gives up electrons and becomes NAD+. The body constantly cycles between these forms, which is central to normal metabolism.
• NAD-dependent cell signaling: NAD+ is used by enzymes including sirtuins, PARPs and CD38-related enzymes, which are involved in DNA repair, metabolism, cellular stress responses and gene regulation.

Direct human NAD+ research. Direct IV NAD+ has been shown to enter human metabolism. In a 2019 pilot study, NAD+ was infused at 3 μmol/min for 6 hours; infused NAD+ was rapidly removed from the blood early in the infusion and processed into related metabolites. This shows that infused NAD+ enters and affects human NAD-related metabolism. It does not show that NAD+ infusion treats fatigue, improves memory, reverses aging, causes fat loss, improves sports performance, treats addiction or repairs mitochondria in otherwise healthy people.

What has it not been proven to help with?

Direct NAD+ injections have not been convincingly established as treatments for:

• aging, longevity or preventing age-related disease
• general chronic fatigue or GLP-1-related fatigue
• bodybuilding, muscle growth or athletic performance
• fat loss
• brain fog or depression
• hangovers, alcohol detoxification or liver detoxification
• opioid or substance-use disorder
• mitochondrial "rejuvenation"
• DNA repair as a measurable clinical outcome

NAD+ is involved in many of these biological systems. That does not show that injecting extra NAD+ produces a meaningful treatment effect.

Dosing evidence

FDA-approved dosing

There is no FDA-approved general NAD+ injection protocol, and no FDA-approved NAD+ injection dose for energy, wellness, anti-aging, fatigue, weight loss or athletic recovery. Compounded NAD+ products exist, but that is not the same as an FDA-approved NAD+ drug.

Human research dosing

• 2019 IV metabolism study: NAD+ infused at 3 μmol/min for 6 hours. A metabolism and pharmacology study, not designed to establish a wellness dose.
• 2026 IV tolerability study: 500 mg NAD+ IV on 4 consecutive days. Participants receiving NAD+ had more infusion-related symptoms (stomach and digestive symptoms, increased heart rate, chest pressure) than those receiving IV nicotinamide riboside. This was mainly a tolerability comparison and does not show that 500 mg is the ideal treatment dose.
• 2026 IM / SC / IV-push pilot: a preliminary safety analysis reported small groups receiving 100 mg NAD+ by IM, SC or IV-push on 3 consecutive days. This report is a preprint that has not yet been through full peer review, and the groups were very small. It shows preliminary controlled human exposure to 100 mg NAD+ by IM and SC injection; it does not make 100 mg IM or SC a clinically proven treatment dose. It is preliminary safety and tolerability evidence, not efficacy evidence.

These are research exposures, not approved wellness doses.

Research-community dosing

Community protocols are much more developed than the clinical evidence. They have not been validated in controlled trials.

PeptideFox. IM: approximately 50–200 mg per injection, commonly 2–3 times per week during more active use, with less frequent maintenance schedules also discussed. SC: approximately 50–100 mg per dose, often as smaller divided injections because SC NAD+ can be uncomfortable or irritating. Lower starting doses around 25 mg are also discussed for tolerance testing. The upper ends of these ranges have not been validated by completed human dose-finding trials.

PeptideDosages. Describes an SC ladder for approximately 8–16 weeks:

• Week 1: 50 mg SC daily
• Week 2: 75 mg SC daily
• Week 3 onward: 100 mg SC daily

The 50 to 75 to 100 mg ladder and the 8–16 week cycle have not been shown in a matching clinical NAD+ efficacy trial.

Clinic / community IV. Some IV clinics use 500–1,000 mg IV and short high-dose loading series, for example 4–5 IV sessions over about 2 weeks.

Protocol comparison

There is no validated universal NAD+ injection protocol.

Frequency

Human research has used very different schedules: continuous IV infusion over 6 hours, 500 mg IV on four consecutive days, and 100 mg by IM, SC or IV-push over three consecutive days in a small preliminary analysis. There is no single clinically established NAD+ injection frequency for general wellness.

In community use, IM is commonly 2–3 times weekly, and SC ranges from several times per week to daily depending on the protocol. The best-supported frequency is unknown: human research does not show that daily SC, 3x-weekly IM, weekly IM or monthly IV is clearly better for general metabolic health.

Timing

There is no established requirement to take NAD+ in the morning, at night, fasted, before or after exercise, or with carbohydrates. Morning use is common because NAD+ is marketed for energy and some users describe feeling more alert; that is a community preference, not a proven timing rule.

Duration and cycling

There is no universal NAD+ treatment cycle. Direct-NAD+ human studies have used one prolonged IV exposure, several consecutive treatment days, and short experimental protocols. Community schedules include short IV "loading" series, 8–16 weeks of SC injections, intermittent IM injections and weekly maintenance use.

No receptor-reset cycle has been established. NAD+ is not a conventional receptor agonist, and there is no established reason for 5 days on / 2 days off, 8 weeks on / 4 weeks off, 12-week receptor resets or mandatory washouts.

Expected results timeline

Direct human research

• Minutes to hours: administered NAD+ enters metabolism quickly. In the 2019 IV study, circulating NAD+ did not keep building up in the blood; it was rapidly removed, broken down, recycled and converted into related metabolites. A biochemical change is not the same as feeling more energetic.
• Several days: short multi-day studies mainly provide tolerability information, not evidence of anti-aging, sustained energy improvement or better cognition.
• Weeks to months: no strong controlled direct-NAD+ study establishes a predictable wellness-results timeline.

There is no strong human clinical evidence for a timeline such as more energy on day 1, better thinking at week 1, improved mitochondria at week 2, or better body composition at week 4 from direct NAD+ injections.

Commonly reported community timeline

• Same day, or hours to days: some people report alertness, energy, recovery or general wellness after IV or injected NAD+.
• Several weeks: community protocols describe steadier energy, recovery and mental clarity during repeated treatment.

These are anecdotal reports and have not been established as controlled clinical outcomes.

Protocol logic check

Does daily SC dosing make sense?

PeptideDosages uses 50 to 75 to 100 mg SC daily. There is now preliminary human exposure to 100 mg SC on three consecutive days, so short-term repeated SC use is no longer supported only by anecdotes. The early research does not validate 8, 12 or 16 weeks of use, permanent 100 mg daily use, anti-aging benefit or energy improvement.

Does 2–3 times weekly IM make sense?

Community protocols commonly use 50–200 mg IM about 2–3 times weekly. The 2026 preliminary analysis gives initial controlled human experience with 100 mg IM, but does not validate 200 mg IM, chronic 2–3x-weekly dosing, long-term use or wellness efficacy.

Morning, fasted and pre-workout dosing

There is no clinical evidence that morning dosing produces better energy, metabolism, cognition or exercise performance. There is no good direct-NAD+ evidence that fasting improves absorption, cellular uptake, energy, mitochondrial effects or fat loss. NAD+ being important for cellular energy metabolism does not show that injecting it before exercise improves performance.

Does NAD+ need a loading phase?

Some IV clinics use several high-dose infusions over a short period, such as 4–5 IV sessions over about 2 weeks. No randomized human trial has established this as the best way to "restore" NAD+ in otherwise healthy adults; it is a clinic and community convention.

8–16 week cycles and receptor resets

There is no known biological event at week 8, 12 or 16 that means NAD+ must be stopped; 8–16 week cycles are a community framework. NAD+ does not act like a conventional receptor-stimulating drug, so there is no NAD receptor reset, receptor desensitization cycle or 2–4 week recovery period.

Dose escalation / titration

Starting lower may make practical sense because injected NAD+ can be uncomfortable, but the 50 to 75 to 100 mg community ladder is a tolerability-based community schedule, not a medically established titration schedule.

Does route matter?

Most historical direct-NAD+ human research is IV. Very early controlled human exposure now exists at 100 mg for both IM and SC. Community use covers all three routes. The routes are not interchangeable simply because they contain NAD+: they may differ in exposure, discomfort, metabolism, tolerability and dosing needs.

IV infusion speed

In a study using 500 mg IV NAD+, participants experienced GI symptoms, increased heart rate and chest pressure, and the NAD+ infusions took much longer than the comparison infusions because symptoms limited how quickly NAD+ could be given. Infusion speed can strongly affect tolerability, and faster is not better. Chest pressure, nausea or severe discomfort during rapid infusion are not "proof the NAD+ is working".

Mechanism and pharmacokinetics

What does NAD+ do?

NAD+ does not work like a receptor drug (for example liraglutide on the GLP-1 receptor, or tesamorelin on the GHRH receptor). It takes part directly in cellular chemistry as a reusable helper molecule: it repeatedly accepts electrons, carries them and gets recycled while the body turns nutrients into energy. It is also used by enzymes involved in DNA repair, metabolism, cellular stress responses and gene regulation. Its biological role is extremely well established, but it has no single therapeutic receptor target.

NAD+ vs NADH

These are two forms of the same redox system (NAD+ ⇄ NADH). NAD+ is the oxidized form, which can accept electrons; NADH is the reduced form, which carries electrons. The body constantly converts one into the other. Research on NADH does not automatically apply to injected NAD+; they are closely related biologically but are not the same administered product.

NAD+ vs NR vs NMN

A study showing that oral NR raises NAD+ does not show that injecting NAD+ has the same effect or benefit. Each molecule and route needs its own evidence. Precursor research (NR, NMN, niacin, nicotinamide) teaches a great deal about NAD metabolism, but it is not NAD+ injection evidence.

Does injected NAD+ go straight into cells?

Not that simply. NAD+ is a relatively large, charged molecule. Outside cells it can be broken down, converted and recycled into other NAD-related compounds before components are taken up and reused. The 2019 human IV study showed that infused NAD+ was rapidly removed from the blood and processed into related metabolites. Injected NAD+ enters human metabolism, but it does not travel intact from the syringe into every mitochondrion, and claims of "100% bioavailable directly into your mitochondria" are misleading.

Human half-life

No simple, clinically useful injection half-life is established. Direct NAD+ is rapidly metabolized, broken down, recycled and converted through multiple pathways, so a dosing schedule built from one plasma half-life number would be misleading.

How long do the effects last?

Unknown. Even if extracellular NAD+ is processed quickly, downstream metabolites may last longer, intracellular NAD pools may behave differently, and biological effects may outlast circulating NAD+. There is not enough direct human injection research to say how long one SC or IM dose "works" or when another dose is physiologically required.

Does it build up with repeated use?

Possibly, at the level of metabolites, intracellular NAD pools and related compounds, depending on route and exposure. Injected NAD+ is heavily processed, and clinically useful accumulation data are limited.

What studies have found

2019 human IV metabolism study

NAD+ was infused for 6 hours at 3 μmol/min. Blood NAD+ did not simply rise immediately; infused NAD+ was rapidly removed from plasma, metabolized and converted into related compounds. This shows that administered NAD+ enters human metabolism, that extracellular metabolism is important, and that IV delivery does not mean intact NAD+ stays in circulation. It does not support anti-aging, more energy, fatigue treatment or cognitive enhancement.

2026 IV NAD+ research

Participants received 500 mg IV NAD+ for 4 consecutive days. The NAD+ group experienced more GI symptoms, heart-rate increases and chest pressure than the IV nicotinamide riboside group. Infusion rate and formulation can strongly affect tolerability; this does not make 500 mg a universally optimal IV dose.

2026 IM / SC / IV-push preliminary safety analysis

A preliminary analysis reported 100 mg NAD+ given by IM, SC or IV-push over three consecutive days. The groups were small and the analysis focused on short-term safety and tolerability. This provides early controlled human exposure to IM and SC NAD+. It does not support chronic 100 mg daily treatment, 200 mg IM protocols, 8–16 week use, anti-aging efficacy, fatigue treatment or increased mitochondrial function.

ClinicalTrials.gov NCT06919328

This registered study is primarily described as research on injectable nicotinamide riboside, including absorption and tolerability across IM, SC and IV-push routes. It documents the broader human injection-research framework. The specific 100 mg NAD+ IM, SC and IV-push findings over three consecutive days come from the separate 2026 preliminary safety analysis.

Four evidence types that are often mixed together

• Normal NAD+ biology: extremely well established; NAD+ is essential to normal human metabolism.
• NAD+ precursor research: NR, NMN, niacin and nicotinamide. Informative about NAD metabolism, but not NAD+ injection evidence.
• Direct human NAD+ research: relatively small; IV metabolism studies, IV tolerability studies, and early preliminary IM / SC / IV-push exposure data.
• Community / clinic protocols: 500–1,000 mg IV, 50–200 mg IM, 50–100 mg SC, loading series, maintenance injections and 8–16 week cycles. Useful to document, but not equivalent to established clinical dosing.

Storage

No universal FDA-approved NAD+ injection exists

There is no approved reference formulation that allows one universal rule for concentration, diluent, sterility period, expiration after opening or reconstitution method.

FDA product-quality warning

The FDA warned compounders against using food-grade NAD+ ingredients for sterile injection products without appropriate pharmaceutical processing, because of contamination, endotoxin and sterility concerns.

Community vials

PeptideDosages describes a 500 mg lyophilized vial mixed with bacteriostatic water, and its community protocol lists approximately 14 days refrigerated after mixing. That does not mean all NAD+ lasts 14 days after reconstitution; different products can have different stability. Storage instructions for the exact product or pharmacy formulation apply.

Contraindications

Formal contraindications

None established. There is no FDA-approved NAD+ injection label, so there is no official contraindication list for injectable NAD+ used for wellness, energy or anti-aging. Theoretical concerns are not formal contraindications.

Important cautions

• Significant cardiovascular disease / cardiovascular symptoms during IV use: higher-dose IV NAD+ has been associated with increased heart rate, chest pressure and significant infusion discomfort.
• Sterile product quality: contamination and endotoxin exposure are serious risks for poorly prepared injectable products; sterility and endotoxin control are critical.
• Pregnancy / breastfeeding: there is not enough direct injectable-NAD+ safety evidence. Safety unknown.
• Long-term IM / SC use: controlled long-term safety is not established.

Side effects

Human IV research

Reported infusion effects include nausea, abdominal discomfort, other GI symptoms, increased heart rate and chest pressure. In a 500 mg IV study, NAD+ infusions took considerably longer than comparison infusions because symptoms limited how quickly they could be given.

IM / SC

Controlled human evidence is still extremely limited. The preliminary 100 mg analysis did not report severe unexpected treatment-related events, but each route group included only a small number of people. This is early short-term tolerability data, not established long-term safety. Local discomfort is also commonly reported in community use.

Contaminated or poor-quality injectable products

The FDA has received adverse-event reports after compounded NAD+ injections involving severe chills, shaking, vomiting and fatigue; some people required medical treatment. The FDA said these reactions were consistent with excessive endotoxin exposure, and warned that food-grade NAD+ ingredients are not appropriate for sterile drug compounding without proper pharmaceutical processing.

This does not mean NAD+ itself caused every reaction. Side effects caused by NAD+ itself are separate from reactions caused by contaminated or poorly manufactured injectable products, which can cause serious harm even when the active ingredient is not the main problem.

Regulatory status

The FDA has raised concerns about ingredient quality, sterile production, endotoxin contamination and regulatory eligibility for some compounded NAD+ products.

2026 503B enforcement

In a January 2026 warning letter to a registered outsourcing facility, the FDA stated that NAD+ did not appear on the 503B Bulks List, and that products compounded from bulk NAD+ by the cited facility therefore did not qualify for the relevant 503B exemptions. This does not mean all NAD+ compounding is illegal: the rules depend on the type of compounding facility, the regulatory pathway, the exact substance, the specific product and applicable compounding law.

Compatibility

Stack / pairing logic

Sources

1. Grant et al. 2019. Human IV NAD+ metabolism. Human metabolism research: direct IV NAD+ administration, 6-hour infusion, rapid plasma processing, NAD-related metabolite changes. pubmed.ncbi.nlm.nih.gov/31572171
2. Reyna et al. 2026. IV NAD+ vs IV nicotinamide riboside. Human tolerability research: 500 mg NAD+ IV on four consecutive days, GI symptoms, increased heart rate, chest pressure, slower NAD+ infusion due to tolerability. pubmed.ncbi.nlm.nih.gov/41704678
3. ClinicalTrials.gov. NCT06919328. Registered human injection study of nicotinamide riboside across IM, SC and IV-push routes; human injection tolerability framework. clinicaltrials.gov/study/NCT06919328
4. Nkrumah-Elie et al. 2026. Preliminary safety analysis (preprint). 100 mg NAD+ by IM, SC and IV-push over three consecutive days; preliminary short-term tolerability findings, not a peer-reviewed efficacy trial. medrxiv.org
5. U.S. FDA. FDA reminds compounders to use ingredients suitable for sterile compounding. Food-grade NAD+ concerns, sterile compounding concerns, endotoxin risk, reports of severe chills, shaking, vomiting and fatigue. fda.gov
6. U.S. FDA. Warning letter to GenoGenix LLC, January 2026. 503B regulatory concerns, bulk NAD+ compounding, endotoxin and product-quality concerns involving NAD+ products. fda.gov
7. PeptideFox. NAD+ guide. Community / practitioner protocols: IM 50–200 mg, SC 50–100 mg, 2–3x-weekly IM use, community IV protocols, route tolerability, loading-series practices. peptidefox.com
8. PeptideDosages. NAD+ 500 mg / 10 mL vial dosage protocol. Community protocol: 50 to 75 to 100 mg SC titration, daily use, 8–16 week framework, community reconstitution and storage guidance. peptidedosages.com