NAD+
Nicotinamide Adenine Dinucleotide (injectable)
The NAD+ coenzyme itself, injected rather than built from a precursor. Distinct from NMN and NR, which are the oral precursors already in this library: those are single molecules that cells import and phosphorylate, while NAD+ is the finished dinucleotide. The pharmacological problem is delivery. NAD+ is large and charged and does not cross an intact cell membrane, so an infused or injected dose is broken down outside the cell by CD38 and CD73 into nicotinamide, NMN and NR before anything is taken up. Grant 2019, the only published human PK study of infused NAD+, found plasma NAD+ did not rise at all during the first 2 hours of a 6 hour infusion. A 2026 PRISMA systematic review (Gallagher) identified no outcomes trial of intravenous or intramuscular NAD+ for anti-aging or wellness. Injectable NAD+ is not an FDA-approved drug; it is supplied by compounding pharmacies and infusion clinics, while oral NAD+ precursors are sold as dietary supplements.
At a glance
- Routes
- SubQ · IV
- Vial sizes
- 100 mg · 500 mg · 1000 mg
- Evidence base
- 4 studies 1 human · 2 review · 1 preclinical
Mechanism
NAD+ is the redox cofactor for hundreds of dehydrogenases and the consumed substrate for sirtuins (SIRT1-7), PARPs and CD38. Tissue NAD+ falls with age, which is the entire rationale for the category. The argument for injecting rather than swallowing is first-pass metabolism: Liu 2018 showed that intravenous NR and NMN reach multiple tissues intact, while the same molecules given orally are converted to nicotinamide in the liver first. What actually enters a cell after an NAD+ injection is still the breakdown products. Extracellular NAD+ is hydrolyzed by CD38 to nicotinamide plus ADP-ribose and dephosphorylated by CD73 to NR, which re-enters the salvage pathway through NRK kinases and NMNAT. Injected NAD+ is therefore best understood as an expensive, rapidly cleaved precursor delivery, not as direct loading of the intracellular pool.
Dosing
Any amounts shown here are reported from published studies only. 1 of 4 catalogued studies involved human subjects. COMPOUND does not publish its own dosing guidance.
Where a study reports an amount, it appears in that study's entry below, attributed to the source.
Published evidence
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Human pilot 2019
A Pilot Study Investigating Changes in the Human Plasma and Urine NAD+ Metabolome During a 6 Hour Intravenous Infusion of NAD
n=11 healthy men aged 30-55 (8 infused, 3 control). 750 mg NAD+ intravenously over 6 h (3 micromol/min). Plasma NAD+ and its metabolites were unchanged for the first 2 h, meaning infused NAD+ was removed from plasma as fast as it was delivered. Nicotinamide rose 409% by 6 h; urinary NAD+ and methylnicotinamide increased but urinary nicotinamide did not. The only published human PK data for infused NAD+.
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Review 2026
NAD+ supplementation for anti-aging and wellness: A PRISMA-guided systematic review of preclinical and clinical evidence
113 eligible intervention studies (33 human, 28 of them randomized; 80 rodent), Jan 2010 to Oct 2025. Oral NR and NMN showed consistent biochemical target engagement and good tolerability, but functional, metabolic and vascular outcomes were heterogeneous and often null. No eligible outcomes trial evaluated intravenous or intramuscular NAD+ itself for anti-aging or wellness.
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Review 2025
NAD+ precursor supplementation in human ageing: clinical evidence and challenges
Review of the human evidence. An age-related fall in NAD+ has been shown consistently in only a limited number of human studies, and precursor trials have produced limited efficacy on functional endpoints. Human tissue-level NAD+ data remain sparse and rodent results do not extrapolate straightforwardly.
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Animal in vivo 2018
Quantitative Analysis of NAD Synthesis-Breakdown Fluxes
Isotope-tracer flux quantitation in mice. Intravenous NR and NMN delivered intact molecules to multiple tissues, while the same agents given orally were metabolized to nicotinamide in the liver first. NAD flux varied widely by tissue, high in small intestine and spleen and low in skeletal muscle. The mechanistic basis for the parenteral-route argument.
Reported side effects
- Infusion reaction (rate-dependent)
- Very common Moderate · Chest pressure, abdominal cramping, nausea and flushing are the characteristic response to rapid intravenous NAD+, and they track infusion rate rather than total amount. This is why clinic protocols run over hours instead of as a push.
- Injection site stinging
- Common Mild · Reconstituted NAD+ is acidic. Burning during a subcutaneous injection is a pH effect, not an allergic one.
- Human safety data very limited
- Unknown Moderate · The only published human PK study of infused NAD+ enrolled 11 men (Grant 2019). Gallagher 2026 found no outcomes trial of intravenous or intramuscular NAD+ at all. Repeated parenteral NAD+ has no characterized long-term safety profile in humans.
- Methyl donor consumption (theoretical)
- Theoretical Mild · NAD+ breakdown yields nicotinamide, which is cleared by methylation via NNMT. High repeated exposure is a theoretical draw on methyl donors. NR-SAFE tested the equivalent concern for oral NR and found no change in SAM or homocysteine, so this remains theoretical rather than observed.
Interactions
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NMN Redundant
Same target pool. Injected NAD+ is cleaved to nicotinamide, NMN and NR outside the cell before uptake, so it converges on the identical salvage pathway that oral NMN feeds.
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NR Redundant
Same target pool. CD73 dephosphorylates extracellular NAD+ to NR, which is exactly what oral NR supplies, at a fraction of the cost.
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5-Amino-1MQ Synergy
Opposite ends of the same pathway. NNMT inhibition keeps nicotinamide available for recycling into NAD+, while injected NAD+ floods the pathway with substrate. Mechanistically complementary and never tested together in any species.
Reconstitution and storage
Lyophilized vials are commonly 500 mg or 1000 mg. A 500 mg vial reconstituted with 5 mL bacteriostatic water gives 100 mg per mL, so 10 units on an insulin syringe holds 10 mg. Drip the water slowly down the vial wall; do not shake.
Lyophilized: refrigerate on arrival, protect from light and moisture. Reconstituted: 2-8C, protected from light. NAD+ hydrolyzes in aqueous solution faster than most peptides, and a solution that has yellowed has degraded.