NAD⁺ decline with age is well documented [1]
Tissue and blood NAD⁺ falls with age across species, with CD38 upregulation and PARP activation as identified drivers.
PrecisePep/Peptide Library/NAD⁺
Mitochondrial & Bioenergetic
NAD⁺
nicotinamide adenine dinucleotide · NAD+ · NMN / NR (precursors)
Not a peptide — a coenzyme every cell already depends on. The interesting question is not whether it matters, which is settled, but whether injecting it does anything a much cheaper oral precursor would not.
00 Overview
NAD⁺ is not a peptide and not a drug — it is one of the most fundamental molecules in metabolism. It carries electrons in every redox reaction of energy production, and it is the obligatory substrate for two families of enzymes that matter for ageing: the sirtuins, which regulate metabolic and stress-response gene expression, and the PARPs, which repair DNA.
That NAD⁺ declines with age is well documented, as is the fact that PARP activation during DNA damage and inflammation consumes it. Restoring it is one of the better-motivated ideas in longevity biology.[1]
The dispute is about delivery. Most credible human trial evidence concerns the oral precursors NMN and NR, which reliably raise blood NAD⁺ metabolites and are generally well tolerated — but which have produced modest and inconsistent effects on clinical outcomes.[2] Direct NAD⁺ administration, by IV drip or subcutaneous injection, has much less evidence behind it and a real question mark over whether the intact molecule enters cells at all, or is simply degraded to precursors first.
The bioavailability question
NAD⁺ is a large, charged molecule. Whether it crosses the plasma membrane intact is contested; the prevailing view is that it is largely broken down extracellularly to nicotinamide and other precursors, which are then taken up and resynthesised. If that is right, an expensive NAD⁺ infusion is a costly and uncomfortable way to deliver nicotinamide.
// Mechanism of action
Redox cofactor. The NAD⁺/NADH couple carries electrons through glycolysis, the TCA cycle and oxidative phosphorylation. Without adequate NAD⁺ there is no efficient ATP production — this part is not in dispute at any level.
Sirtuin substrate. Sirtuins are NAD⁺-dependent deacetylases regulating mitochondrial biogenesis, stress resistance and metabolic gene expression. Their activity is limited by NAD⁺ availability, which is the core longevity argument.
PARP substrate. PARP enzymes consume NAD⁺ during DNA repair. Chronic DNA damage and inflammation therefore deplete the pool — a mechanism linking ageing, inflammation and falling NAD⁺.
CD38 consumption. The ectoenzyme CD38 degrades NAD⁺ and increases with age, and is a major driver of the age-related decline. This is why some approaches target CD38 rather than supply.
Why the route matters. Precursors (NMN, NR) use dedicated transport and salvage pathways. Intact NAD⁺ probably does not, which makes the delivery method the central unresolved question rather than a technicality.
01 Reported benefits
Effects that have been reported. A study-tier entry means a result was published — not that the effect is established, reproducible, or transferable from a rodent to a person.
Highest confidenceReported in peer-reviewed literature, registered clinical trials, or regulatory filings. Note the model: much peptide literature is in vitro or rodent work, not human trial data.
Oral precursors reliably raise NAD⁺ metabolites [2]
NR and NMN trials consistently demonstrate increased blood NAD⁺ metabolite levels in humans, with good tolerability.
Clinical outcome effects are modest and inconsistent [2]
Despite reliably raising NAD⁺ markers, precursor trials have produced limited and variable effects on muscle function, insulin sensitivity and other clinical endpoints. This is the honest state of the field.
Improved insulin sensitivity in one NMN trial [3]
A randomised trial in prediabetic postmenopausal women reported improved muscle insulin sensitivity — one of the more positive individual human results.
Very limited direct NAD⁺ trial evidence [4]
IV NAD⁺ has been studied in small settings including substance-use contexts, with weak methodology. It is not comparable to the precursor literature.
Unproven — inference onlyExtrapolated from a known mechanism, receptor profile, or adjacent compound class. Biologically plausible but not directly demonstrated for this compound in this context.
Energy, cognition and general wellbeing
The dominant reason people pay for NAD⁺ infusions. Mechanistically motivated, and not established by the precursor trials that actually measured such outcomes.
Healthspan extension via sirtuin signalling
The core longevity argument, inheriting every unresolved translation problem that field carries.
Supporting mitochondrial peptides
Electron transport requires NAD⁺, so restoring cristae architecture or driving AMPK without adequate NAD⁺ is arguably incomplete. Coherent rationale for the stack; untested.
Injection avoids first-pass metabolism
The argument for parenteral use. It assumes intact NAD⁺ is taken up by cells, which is exactly what is disputed.
Concern: NAD⁺ and tumour metabolism
Rapidly proliferating cells have high NAD⁺ demand, and NAMPT inhibition has been explored as an anti-cancer strategy. Supplying more is the opposite intervention, and it is unstudied.
Uncontrolled reportsAggregated from research-community logs, forums, vendor literature and self-reported experience. Uncontrolled, unverified, subject to placebo, polypharmacy and product-purity confounds. Lowest evidentiary weight.
Marked energy and clarity after IV infusion
The characteristic report from clinic infusions. Also the setting with the strongest expectation effects — an expensive, uncomfortable, hours-long procedure in a clinical environment.
Intense flushing, nausea and chest tightness during infusion
Near-universal if infused quickly, and the reason IV NAD⁺ is administered slowly over hours. It is the most reliable effect the compound produces.
Subcutaneous use is far less dramatic
Reported as milder in both effect and side effects than infusion — consistent with slower absorption.
Precursors reported as subtler but easier
Oral NMN or NR described as less noticeable and far more practical — which is also what the trial data would predict.
Cost is the limiting factor
Clinic infusions are among the most expensive interventions discussed in this space, which shapes usage patterns more than any pharmacological consideration.
02 Adverse effects & risks
Adverse effects, contraindications and unknowns. The grey-market tier is where under-reporting is worst: uncontrolled use produces no systematic safety surveillance at all, so absence of a reported harm is not evidence of safety.
Highest confidenceReported in peer-reviewed literature, registered clinical trials, or regulatory filings. Note the model: much peptide literature is in vitro or rodent work, not human trial data.
Infusion reactions: flushing, nausea, chest tightness, cramping [4]
Dose-rate dependent and near-universal with rapid infusion. Managed by slowing the rate, which is why sessions run for hours.
Oral precursors well tolerated [2]
NR and NMN trials report good safety at studied doses over the durations examined.
No long-term safety data for parenteral NAD⁺
Repeated infusion or injection over years has no characterisation.
Unproven — inference onlyExtrapolated from a known mechanism, receptor profile, or adjacent compound class. Biologically plausible but not directly demonstrated for this compound in this context.
Methyl donor depletion
Excess nicotinamide is cleared by methylation via NNMT, consuming SAM. High-dose precursor use has a theoretical methyl-depletion cost — and note this runs directly opposite to the NNMT-inhibitor rationale elsewhere in these protocols.
Supporting proliferating cells
The oncology counter-consideration. Unstudied for supplementation.
Sterility and technique risk with IV use
Intravenous administration carries infection and access risks that oral precursors simply do not.
Uncontrolled reportsAggregated from research-community logs, forums, vendor literature and self-reported experience. Uncontrolled, unverified, subject to placebo, polypharmacy and product-purity confounds. Lowest evidentiary weight.
Flushing, nausea and chest pressure
The defining experience of IV NAD⁺, and directly rate-dependent.
Injection-site pain with subcutaneous use
Commonly reported.
Headache and fatigue afterwards
Occasionally reported following infusion.
03 Dosing ranges
Figures below are documented, not recommended. Study ranges come from published protocols in the stated model; grey-market ranges are what the research community reports using and carry no safety validation of any kind.
Highest confidenceReported in peer-reviewed literature, registered clinical trials, or regulatory filings. Note the model: much peptide literature is in vitro or rodent work, not human trial data.
Oral precursor trial dosing [2][3]
Human NR and NMN trials have typically used a few hundred milligrams to around a gram daily over weeks to months — the best-characterised dosing in this space by a wide margin.
No established parenteral NAD⁺ dose
IV clinic protocols vary widely and are not standardised or trial-derived.
Unproven — inference onlyExtrapolated from a known mechanism, receptor profile, or adjacent compound class. Biologically plausible but not directly demonstrated for this compound in this context.
Oral precursors are the evidenced route
They have the trial data, the tolerability and a fraction of the cost. If the goal is raising NAD⁺, this is the option with actual human evidence behind it.
Slow administration if infusing
The adverse effects are rate-dependent, which is the one thing about IV NAD⁺ that is not in doubt.
Uncontrolled reportsAggregated from research-community logs, forums, vendor literature and self-reported experience. Uncontrolled, unverified, subject to placebo, polypharmacy and product-purity confounds. Lowest evidentiary weight.
IV: 250–1000 mg per session, over 2–4 hours
Typical clinic infusion protocols, rate-limited by tolerability.
Subcutaneous: 50–100 mg daily
The common at-home approach, milder in both effect and adverse effects. This is a twentieth to a tenth of a typical infusion dose — the difference is injection volume, not a considered pharmacological decision.
Vial arithmetic drives the practice
A 1000 mg vial at 100 mg daily is ten days. Reconstitution volume matters more here than for almost any peptide: 1000 mg in 5 mL is 200 mg/mL, so a 100 mg dose is 0.5 mL — half a 1 mL syringe, and a large subcutaneous volume.
Oral NMN or NR: 250–1000 mg daily
The route with actual trial support.
| Route | Dose | Frequency | Notes |
|---|---|---|---|
| IV infusion | 250 – 1000 mg | Weekly to monthly | Rate-limited by flushing and nausea |
| Subcutaneous | 50 – 100 mg | Daily | Milder; injection-site pain common |
| Oral NMN / NR | 250 – 1000 mg | Daily | Best trial support, lowest cost |
04 Synergy & interactions
Combination effects. Almost no peptide combination has been studied as a combination in humans; stack logic is overwhelmingly mechanistic inference and community practice. Each linked compound has its own page.
Highest confidenceReported in peer-reviewed literature, registered clinical trials, or regulatory filings. Note the model: much peptide literature is in vitro or rodent work, not human trial data.
No combination studies with research peptides
None exists.
Unproven — inference onlyExtrapolated from a known mechanism, receptor profile, or adjacent compound class. Biologically plausible but not directly demonstrated for this compound in this context.
With SS-31 and MOTS-c
Electron transport needs NAD⁺; restoring cristae or activating AMPK without adequate substrate is arguably incomplete. The most coherent stacking rationale for NAD⁺.
With 5-Amino-1MQ
Reduce NAD⁺ consumption while increasing supply — mechanistically complementary, and note the methyl-donor tension between them.
With Epitalon in longevity stacks
Grouped together by framing rather than by any interaction.
Uncontrolled reportsAggregated from research-community logs, forums, vendor literature and self-reported experience. Uncontrolled, unverified, subject to placebo, polypharmacy and product-purity confounds. Lowest evidentiary weight.
Mitochondrial and longevity pillar of the 15-Compound Matrix
Listed with MOTS-c, humanin and Epitalon, with continuous support through the opening quarter.
05 Protocols
Whole schedules — dosing, titration, cycle length, and off-time — as documented in trials, as proposed from mechanism, and as circulated in the research community. Reproduced for study and comparison only.
Highest confidenceReported in peer-reviewed literature, registered clinical trials, or regulatory filings. Note the model: much peptide literature is in vitro or rodent work, not human trial data.
Unproven — inference onlyExtrapolated from a known mechanism, receptor profile, or adjacent compound class. Biologically plausible but not directly demonstrated for this compound in this context.
Start with the precursor, not the infusion
Cheaper, better evidenced, better tolerated and does not require venous access.
Uncontrolled reportsAggregated from research-community logs, forums, vendor literature and self-reported experience. Uncontrolled, unverified, subject to placebo, polypharmacy and product-purity confounds. Lowest evidentiary weight.
Monthly infusions or daily oral
The two common patterns.
15-Compound Matrix — Q1 continuous support
Run continuously through the opening metabolic and mitochondrial quarter.
05b Condition-specific interest
NAD+ is the most heavily marketed compound in this library and the one where the gap between the underlying science and the commercial offering is widest. The biology is real and important. The infusion is a different question, and the answer to it is mostly about molecular size.
No approval, no trial
NAD+ is not a peptide. It is a dinucleotide coenzyme involved in hundreds of redox reactions and in the activity of sirtuins and PARPs. It is not approved for any indication, and the clinical evidence for administering it — by infusion, injection or otherwise — is far weaker than the evidence that NAD+ matters biologically. Those are two different claims and they are routinely merged.
Actionable
The route problem — read this before anything else
Pathophysiology
Not a condition. A pharmacology point that determines how to read every claim below.
Mechanistic rationale
NAD+ is a large, charged molecule that does not readily cross cell membranes. Cells make it from precursors — nicotinamide riboside, nicotinamide mononucleotide, nicotinamide, tryptophan — through salvage and de novo pathways. Administered NAD+ is substantially degraded to those precursors in circulation, which means an expensive infusion may function as a costly way to deliver nicotinamide. That is not a fringe objection; it is the central pharmacological question about the entire category, and the oral precursors that have actual randomised trials behind them are cheap and need no cannula.
Community reports
Infusion clinics rarely raise it. The intense flushing, chest tightness and nausea that make NAD+ infusions notoriously unpleasant are also worth noting — they are why infusions are run slowly over hours.
Components carrying the argument: Molecular size and charge — the whole argument
Theorized — the decline is real, the correction is not
Ageing and the NAD+ decline
Pathophysiology
Tissue NAD+ declines with age across species, driven by increased consumption — by PARPs responding to DNA damage and by CD38 — as much as by reduced synthesis. Lower NAD+ constrains sirtuin activity and mitochondrial function.
Mechanistic rationale
The decline is one of the better-replicated findings in ageing biology, and restoring it improves outcomes in mice. In humans, oral precursors reliably raise blood NAD+ levels in randomised trials — and the clinical benefits have been much harder to demonstrate. Raising a biomarker is the easy part. Whether that translates into anything a person notices or lives longer for is unresolved, and the trials that have looked have mostly been small and short.
Community reports
The dominant reason for use. Reported effects are energy, clarity and wellbeing — the three most placebo-responsive endpoints available.
Components carrying the argument: Sirtuin and PARP substrate availability
Anecdotal — and the differential matters more
Fatigue and energy
Pathophysiology
Fatigue has a long list of common, diagnosable and treatable causes: anaemia, iron deficiency, hypothyroidism, diabetes, sleep apnoea, depression, medication effects, and deconditioning.
Mechanistic rationale
NAD+ is central to cellular energy metabolism, which makes the marketing intuitive — the compound involved in energy production must produce energy. That reasoning does not hold: ATP production is not limited by NAD+ availability in a healthy person, and the intuition is doing the work the evidence should be. The main harm here is opportunity cost — an infusion instead of a blood panel and a sleep assessment.
Community reports
Energy improvement is the near-universal report, in a setting — an expensive infusion in a clinic over several hours — engineered for a large placebo response.
Components carrying the argument: Cellular energy metabolism, generally not rate-limiting
Anecdotal — a large commercial market on almost nothing
Addiction and withdrawal
Pathophysiology
Substance withdrawal has substance-specific physiology. Alcohol withdrawal can cause seizures and delirium tremens; opioid withdrawal is severe and is followed by a period of sharply elevated overdose risk as tolerance falls.
Mechanistic rationale
NAD+ infusion is marketed heavily for addiction and withdrawal, particularly in residential settings, on very little published evidence. The concern is the same one raised on the Selank and DSIP pages: substituting an unproven infusion for benzodiazepine-based alcohol withdrawal management removes seizure protection, and displacing opioid agonist therapy removes the intervention with the strongest mortality evidence in opioid use disorder.
Community reports
Testimonial-driven and commercially promoted. This is the use where the gap between marketing volume and evidence is largest.
Components carrying the argument: Unestablished
Theorized — active research, no clinical answer
Neurodegeneration and neuroprotection
Pathophysiology
Axonal degeneration is an active, programmed process governed substantially by NAD+ metabolism — the SARM1 pathway, in which NAD+ depletion triggers axon destruction, is genuinely important biology.
Mechanistic rationale
This is the most scientifically serious part of the NAD+ field, and it is the reason pharmaceutical interest exists. It is also targeted by SARM1 inhibitors in development rather than by flooding the system with substrate. Trials of NAD+ precursors in Parkinson disease and other conditions are ongoing and have not delivered a clear answer.
Community reports
Cited in neuroprotection contexts, generally without distinguishing the research from the infusion.
Components carrying the argument: SARM1 / axonal NAD+ metabolism
Theorized — no data at all
Subcutaneous injection — the newer grey-market route
Pathophysiology
Not a condition.
Mechanistic rationale
Subcutaneous NAD+ has appeared as a cheaper alternative to infusion. There is no pharmacokinetic characterisation of this route, the doses are a fraction of infusion doses on no established basis, and injection site pain is commonly reported — unsurprising for a large charged molecule in a small volume. If the route question above is unresolved for infusion, it is entirely unexamined here.
Community reports
Growing in popularity, largely on cost. Vial sizes in this market are unusually large, and the calculator flags the mg/mL figure for that reason.
Components carrying the argument: —
| Question | Position |
|---|---|
| Is the NAD+ decline real? | Yes — well replicated across species |
| Do oral precursors raise NAD+? | Yes — shown in randomised trials |
| Do they produce clinical benefit? | Much harder to show — largely unresolved |
| Does infused NAD+ enter cells intact? | Largely not — it is degraded to precursors |
| Cheaper route with actual trials | Oral NR or NMN |
| Addiction / withdrawal | Heavily marketed; do not displace proven treatment |
| Subcutaneous route | No pharmacokinetic data whatsoever |
What actually has evidence for these conditions
For fatigue: exclude the common causes first, because they are common and treatable — full blood count, ferritin, thyroid function, glucose or HbA1c, and a sleep assessment. Depression and medication effects account for a large share of the rest. Graded exercise and sleep regularity have effect sizes nothing in this category has demonstrated.
If NAD+ is the target: oral nicotinamide riboside or nicotinamide mononucleotide raise NAD+ in randomised human trials, cost a fraction of an infusion, and require no cannula. Note the regulatory history on NMN specifically: the FDA had excluded it from the dietary supplement definition, then reversed that position in letters dated 29 September 2025, confirming NMN is not excluded. It remains a new dietary ingredient requiring premarket notification, so availability still depends on the supplier having filed one. That is the evidenced version of this intervention, with the clinical-benefit question still open for all of them.
For alcohol or opioid use disorder: medically supervised withdrawal, benzodiazepines for alcohol withdrawal, thiamine to prevent Wernicke encephalopathy, and opioid agonist therapy — buprenorphine or methadone — which substantially reduces mortality and is the intervention with the best evidence in the field. Naltrexone and acamprosate for alcohol relapse prevention.
06 Handling, reconstitution & storage
Physical-chemistry reference for laboratory handling of the lyophilised material. Reproduced so that stability and concentration mathematics can be studied — see the calculator for the arithmetic and the reconstitution guide for sterile technique.
Reconstitution
Supplied as a lyophilised powder, commonly 500 or 1000 mg per vial in the research market, or as oral capsules of the precursors. NAD⁺ solutions are unstable and are normally prepared close to use. Subcutaneous doses in the tens to low hundreds of milligrams mean the concentration choice determines whether the injection volume is tolerable — larger dilutions give a more comfortable injection but a bigger bleb.
Storage
Powder: refrigerated or frozen, protected from light and moisture. Reconstituted: refrigerated and used promptly — NAD⁺ degrades faster in solution than most peptides.
Common vial sizes
Commonly 1000 mg vials; precursors as oral capsules.
Stability notes
NAD⁺ is chemically labile in aqueous solution and sensitive to pH and temperature. A vial that has been reconstituted for weeks is not delivering what the label says.
07 Legal & regulatory status
Regulatory status changes and differs by country. This is a summary for orientation, not legal advice — check your own jurisdiction.
Not an approved therapeutic. NAD⁺ itself has no marketing approval. IV NAD⁺ infusions are offered by wellness clinics under practice-of-medicine arrangements rather than on the basis of an approved indication.
The precursors sit differently: nicotinamide riboside has US new dietary ingredient status and is sold as a supplement, while the supplement status of NMN in the United States has been contested by the FDA on the basis that it was investigated as a drug. Status varies by jurisdiction and has been changing.
Regulatory and trial claims re-checked against primary sources on 16 August 2026. Checked: FDA reversal on NMN dietary-supplement status, 29 September 2025. Approvals, trial readouts and compounding decisions move faster than anything else on this page — a date here means someone looked, not that nothing has changed since.
Anti-doping
Athletes subject to WADA, USADA, UKAD, NCAA or military testing should assume any peptide is prohibited unless they have verified otherwise against the current WADA Prohibited List. Several classes here (growth-hormone secretagogues, TB-4 analogues, metabolic modulators) are explicitly named. Check the current list — it is republished annually.
§ Sources & further reading
Links resolve to PubMed records, trial registries, publisher pages or primary documents. Where a body of work rather than a single paper is cited, the link opens a PubMed query so the full result set — including newer papers than this page — can be reviewed. Verify every claim against the primary source before relying on it.
- PubMed: NAD⁺ decline with age, CD38 and PARP consumption (live query)Database or literature search
- PubMed: nicotinamide riboside and NMN human randomised trials (live query)Database or literature search
- Yoshino M, et al. Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women. Science. 2021.Registered clinical trial
- PubMed: intravenous NAD⁺ administration in humans — the limited direct evidence (live query)Database or literature search
Reminder
For educational and research reference only. Nothing on this site is medical advice, a recommendation, or an instruction to administer any substance to a human being. Every figure on this page is a record of what has been reported, not a recommendation. Full disclaimer.