Why does NAD+ injection hurt?
The formulation is often acidic and hypertonic and the volume is large; several vendors now sell 'pH-adjusted' NAD+ for this reason. Whether that helps has not been studied.
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Tier 1 — Human RCT
NAD+
Mitochondrial Bioenergetics & Sirtuin Activation
Nicotinamide Adenine Dinucleotide (Oxidized Form)
Last reviewed: August 2026
Research Purposes Only. NAD+ is supplied by Purgo Labs strictly for qualified laboratory research use only. It is not intended for human or veterinary use, nor for diagnostic, therapeutic, or cosmetic application. Statements on this page have not been evaluated by the FDA.
CR
Written By
Compound Review Research Team
Reviewed for Scientific Accuracy By
Megan FleuryPharmD, MBA, RP
Reviewed the scientific, mechanism, and research content on this page. This review does not cover dosing protocols or sourcing/vendor information, which are provided separately for research reference only.
Reviewed: August 2026
All content is reviewed for scientific accuracy against peer-reviewed literature. View our editorial methodology.
So What Does This Actually Mean?
Plain English summary — no PhD required
NAD+ (Nicotinamide Adenine Dinucleotide) is a molecule your body makes from vitamin B3 that every single cell in your body depends on to produce energy. Think of it as the rechargeable battery inside each cell. The problem is that NAD+ levels decline significantly with age — by your 50s, you may have roughly half the NAD+ you had at 20 — and this decline is strongly associated with the hallmarks of aging.
What It Does
NAD+ is a coenzyme that sits at the center of cellular energy production (the Krebs cycle and electron transport chain). But beyond energy, it's the essential fuel for a class of proteins called sirtuins — often called 'longevity proteins' — which regulate DNA repair, inflammation, circadian rhythms, and metabolic efficiency. NAD+ is also required by PARP enzymes, which are your cells' primary DNA damage repair machinery. When NAD+ is abundant, these systems run efficiently; when it's depleted, they slow down.
Why It Matters
The connection between NAD+ decline and aging is one of the most actively researched areas in longevity science. David Sinclair's lab at Harvard has published extensively on this, and multiple human clinical trials are underway studying NAD+ precursors (NMN, NR) for age-related conditions. Research-grade NAD+ allows direct study of the molecule itself, rather than precursors that must be converted by the body.
The Bottom Line
NAD+ is arguably the most important molecule in longevity research right now. Its role in sirtuin activation, DNA repair, and mitochondrial function makes it central to understanding why we age. The research-grade NAD+ supplied by Purgo Labs is for laboratory use only. If you've heard of NMN or NR supplements, those are precursors that your body converts to NAD+ — this is the actual molecule.
Overview
What is NAD+?
Nicotinamide adenine dinucleotide (NAD+) is a dinucleotide coenzyme found in every living cell, where it serves as an indispensable electron carrier in cellular respiration and as a substrate for a growing family of regulatory enzymes. Unlike the peptides in this guide, NAD+ is not a synthetic compound — it is a naturally occurring biomolecule that has been the subject of Nobel Prize-winning research since Otto Warburg's foundational work on cellular respiration in the 1930s.
The renewed scientific interest in NAD+ stems from a convergence of discoveries in the early 2000s: the identification of sirtuins as NAD+-dependent deacylases with profound effects on aging and metabolic regulation, the demonstration that NAD+ levels decline significantly with age across multiple species, and the development of NAD+ precursors (NMN and NR) as research tools for restoring NAD+ pools.
Key Takeaways
- NAD+ (Nicotinamide Adenine Dinucleotide) is a dinucleotide coenzyme present in every living cell, functioning as the central electron carrier in cellular respiration and as a required substrate for Sirtuins (SIRT1–SIRT7), PARP enzymes, and CD38 — all critical regulators of aging and DNA repair.
- NAD+ levels decline approximately 50% between ages 20 and 60 in human tissue, correlating with reduced mitochondrial function, impaired DNA repair capacity, and increased inflammatory signaling (the 'NAD+ decline' hypothesis of aging).
- Three main precursor pathways: NMN (nicotinamide mononucleotide) and NR (nicotinamide riboside) both enter the salvage pathway to regenerate NAD+; direct IV NAD+ bypasses precursor conversion but has a very short plasma half-life.
- Human clinical evidence: NR supplementation consistently elevates blood NAD+ (Trammell et al., Nature Communications 2016); NMN improved muscle insulin sensitivity in postmenopausal women with prediabetes (Yoshino et al., Science 2021); 2025 Lancet eClinicalMedicine study found NR improved cognition in older adults with MCI.
- Sirtuin activation by NAD+ deacetylates histones and transcription factors including PGC-1α (mitochondrial biogenesis), FOXO3 (stress resistance), and p53 (apoptosis regulation) — the mechanistic basis for NAD+'s proposed longevity effects.
Composition
Molecular Composition
Amino Acid Sequence
C₂₁H₂₇N₇O₁₄P₂ (dinucleotide coenzyme)
NAD+ (nicotinamide adenine dinucleotide, oxidized form) is a dinucleotide consisting of two nucleotides joined by a pyrophosphate linkage: adenosine monophosphate (AMP) and nicotinamide mononucleotide (NMN). The nicotinamide ring — derived from vitamin B3 (niacin) — is the functional redox-active component, capable of accepting a hydride ion (H⁻) to become NADH.
The molecular formula is C₂₁H₂₇N₇O₁₄P₂ with a molecular weight of 663.43 Daltons. NAD+ exists in two interconvertible forms: the oxidized form (NAD+) and the reduced form (NADH). The ratio of NAD+ to NADH is a critical indicator of cellular redox state and metabolic health.
Mechanism of Action
How Does It Work?
!
NAD+ restores cellular energy and activates longevity enzymes (sirtuins and PARPs) by replenishing the coenzyme that powers mitochondrial ATP production and DNA repair.
NAD+ functions through two fundamentally distinct mechanisms: as a redox coenzyme in metabolic reactions, and as a substrate for regulatory enzymes that consume it in non-redox reactions.
In its coenzyme role, NAD+ accepts electrons from metabolic substrates during glycolysis, the TCA cycle, and beta-oxidation of fatty acids, becoming NADH. NADH then donates these electrons to the mitochondrial electron transport chain (ETC), driving ATP synthesis via oxidative phosphorylation.
In its substrate role, NAD+ is consumed by three classes of enzymes: (1) Sirtuins (SIRT1-7) — NAD+-dependent deacylases that regulate gene expression, mitochondrial biogenesis, DNA repair, and metabolic adaptation. (2) PARPs — enzymes that consume NAD+ to coordinate the DNA damage response. (3) CD38/CD157 — NAD+ glycohydrolases involved in calcium signaling and immune function, which become increasingly active with age.
"NAD+ can directly and indirectly influence many key cellular functions, including metabolic pathways, DNA repair, chromosomal integrity, epigenetic and posttranslational modifications, immune cell function, and aging." — Covarrubias et al., Nature Reviews Molecular Cell Biology, 2021
Signaling Pathways
Key Research Pathways
Sirtuin Activation (SIRT1–7)
NAD+-dependent deacylases that regulate gene expression, mitochondrial biogenesis, DNA repair, and metabolic adaptation across all tissues.
Mitochondrial Electron Transport
NADH (reduced form) donates electrons to Complex I of the ETC, driving ATP synthesis — the fundamental energy currency of all aerobic cells.
PARP-Mediated DNA Repair
PARPs consume NAD+ to synthesize poly-ADP-ribose chains at DNA damage sites, coordinating the DNA damage response and maintaining genomic integrity.
CD38 / Calcium Signaling
CD38 glycohydrolase consumes NAD+ to produce cyclic ADP-ribose, a second messenger regulating intracellular calcium and immune cell function.
Research Highlights
Key Findings from the Literature
- NAD+ levels decline 40–60% between ages 20–60, correlating with hallmarks of aging (Covarrubias et al., 2021)
- Sirtuin activation by NAD+ extends lifespan in C. elegans and improves healthspan in rodent models
- SIRT1/SIRT3 activation promotes mitochondrial biogenesis via PGC-1α pathway
- PARP-dependent DNA repair consumes NAD+; restoration improves genomic stability
- NAD+ supplementation reduces age-related inflammation (inflammaging) in preclinical models
- Cognitive benefits in early Alzheimer's disease models (Science Daily, 2026)
Outcome Matrix
Evidence by Claimed Outcome
Each outcome rated by the highest level of evidence available. Tiers follow our 5-tier methodology.
StrongModeratePreliminaryPreclinicalTheoretical
Claimed Outcome
Evidence Tier
Studies
Key Evidence Note
NAD+ level restoration
Strong
12
Multiple Phase I/II trials confirm oral/IV NAD+ precursor efficacy
Mitochondrial function
Moderate
6
Phase II data; SIRT1/SIRT3 activation confirmed mechanistically
Cognitive function
Preliminary
3
Small RCTs; not powered for cognitive endpoints
Longevity / aging hallmarks
Preliminary
4
Observational data; Phase III trials ongoing (CALERIE-2)
Study counts reflect peer-reviewed publications in the evidence database below. "Theoretical" outcomes have mechanistic rationale only. Learn about our evidence tiers →
Evidence Database
Structured Evidence Table
1 cited study — model, sample size, outcome, and effect size from published literature.
| Study | Model | Sample | Outcome | Effect Size | Level |
|---|---|---|---|---|---|
Yoshino J, et al. (2018) NAD+ Intermediates: The Biology and Therapeutic Potential of NMN and NR PubMed | Review — human + rodent | Review | NAD+ precursors improve mitochondrial function, insulin sensitivity, and aging biomarkers | NAD+ levels: 40–90% increase with NMN/NR supplementation in humans | RCT |
Yoshino J, et al. (2018)
NAD+ Intermediates: The Biology and Therapeutic Potential of NMN and NR
Model
Review — human + rodent
Sample
Review
Effect Size
NAD+ levels: 40–90% increase with NMN/NR supplementation in humans
Evidence levels:RCTPhase IIIPhase IIObservationalAnimalIn Vitro
Evidence table is for educational reference only. Most peptide research is preclinical. Human RCT data is limited for most compounds. All compounds are for research purposes only — not for human use.
Researcher Notes
Important Research Context
NAD+ research has accelerated dramatically since 2013, with multiple human clinical trials now completed or underway. A 2023 meta-analysis in The Journals of Gerontology found that NMN and NR supplementation consistently elevated blood NAD+ levels in human subjects. A 2025 Lancet eClinicalMedicine study found that nicotinamide riboside supplementation improved cognitive performance in older adults with mild cognitive impairment.
Research References
Peer-reviewed literature supporting the research profile of NAD+
The following peer-reviewed studies form the primary evidence base for NAD+'s research profile. All references are sourced from PubMed, NCBI, and peer-reviewed scientific journals. Published research is available through PubMed, NCBI, and peer-reviewed biomedical journals.
- 1.
Yoshino J, Baur JA, Imai SI. NAD+ Intermediates: The Biology and Therapeutic Potential of NMN and NR. Cell Metabolism. 2018.PMID: 29249689
Comprehensive review of NAD+ precursor biology and therapeutic potential in aging and metabolic disease.
- 2.
Rajman L, Chwalek K, Sinclair DA. Therapeutic Potential of NAD-Boosting Molecules: The In Vivo Evidence. Cell Metabolism. 2018.PMID: 29514064
In vivo evidence for NAD+ supplementation in longevity, metabolic health, and neuroprotection.
- 3.
Martens CR, et al. Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD+ in healthy middle-aged and older adults. Nature Communications. 2018.PMID: 29599478
First human clinical trial confirming oral NAD+ precursor supplementation safely elevates blood NAD+ levels.
Research Databases
NAD+
Longevity Research
From $59.99
Purgo Labs list price, read 12 Sep 2026 · per-lot COA on the vendor page
1 vial (500mg)
List price · read 12 Sep 2026
$59.99
1 vial (1000mg)
List price
$69.99
1000mg $69.99 → $55.99 with code HEALTH (20% off; price read 2 Oct 2026)
Where to buy NAD+
22 partners · prices read from product pages, latest 1 Nov · ranked by rubric, then price
- 1 certificate verified at the lab1000mg$69.99→ $55.99
- 2 certificates verified at the lab500mg$35.00→ $28.00
- 1 certificate verified at the lab500mg$59.99$35.99→ $32.39
Every order also needs bacteriostatic water — add it to the same cart.All NAD+ vendors, partners and not
Fast FedEx shipping · Discreet packaging
Sourced from Purgo Labs
✅≥99% Purity
📋COA Verified
🏭cGMP Made
Technical Specifications
- Compound Class
- Dinucleotide coenzyme (not a peptide)
- Molecular Formula
- C₂₁H₂₇N₇O₁₄P₂
- Molecular Weight
- 663.43 Da
- Redox Forms
- NAD+ (oxidized) / NADH (reduced)
- Natural Occurrence
- All living cells; declines with age
- Available Sizes
- 500mg vials
- Form
- Lyophilized powder
- Purity
- ≥99% (third-party tested)
Legal Status
Supplement / OTC
View full legal status guide →
Interaction Guides
Source NAD+ at Purgo Labs
1000mg $69.99 list · $55.99 with code HEALTH · lab-verifiable COA per lot
Vendor Scoreboard — top 3 by verified evidenceVerified 1 November 2026
Related Research
Other Compounds in This Guide
Safety
NAD+ side effects
Human trial dataSmall human studies of intravenous NAD+ and larger trials of oral precursors — no approval
Intravenous NAD+ has been given in small clinical studies; the consistent finding is that adverse effects are infusion-rate-dependent — chest tightness, nausea, cramping and flushing when given quickly, resolving when slowed. Subcutaneous NAD+ has essentially no published safety data. Oral precursors (NR, NMN) have been through placebo-controlled trials with benign profiles.
Research-use information only. Research-grade NAD+ is not an approved medicine; where trial or label figures appear below they belong to the pharmaceutical product studied, not to any research vial. This section does not give dosing or medical advice.
What is reported
Every rate carries its source. Where no source exists, no rate is printed.
| Effect | Rate (sourced) | Detail | Source |
|---|---|---|---|
| Infusion-rate effects (chest pressure, nausea, abdominal cramping, flushing) | not quantified | Reported with IV NAD+ when infused rapidly; abated with slower rates. | Grant et al. 2019 |
| Oral precursors (NR, NMN) | not quantified | Placebo-controlled trials up to 12 weeks report adverse events similar to placebo. | Martens et al. 2018 (NR); Yoshino et al. 2021 (NMN) |
What is not known
- •Subcutaneous NAD+ — no controlled data.
- •Long-term effects of raising NAD+ pharmacologically.
Mechanism-based cautions
- •Injection-site pain is commonly reported informally for subcutaneous NAD+; unquantified.
- •Theoretical concern that boosting NAD+ could support tumour metabolism; unresolved in the literature.
Regulatory status: Not approved as a drug; sold as a research chemical and, for oral precursors, as supplements.
Side-effect references
- Grant R, et al. A pilot study investigating changes in the human plasma and urine NAD+ metabolome during a 6 hour intravenous infusion of NAD+. Frontiers in Aging Neuroscience, 2019.
What is actually in a research vial
Everything above describes NAD+ the molecule. The risk specific to a research vial is different: it may not contain NAD+ at the labelled amount, and it may contain what the synthesis left behind. Identity (mass spectrometry), purity (HPLC), measured net content and an endotoxin result are the four lines on a certificate that bear on adverse effects, and only a certificate you can check at the laboratory tells you any of them. This is what we have verified for NAD+ so far.
Who sells NAD+, and what they document
60 of the 105 vendors on our scoreboard list NAD+ with a price we read on the product page (5 Sep 2026–1 Nov 2026). Of those, 55 name their testing laboratory, 44 publish certificates that resolve on the lab's own site, and 52 publish measured milligrams against the label. The full ranking, with every dated price, is on Best NAD+ Vendors.
| Vendor | Rubric | Lab named | Price read |
|---|---|---|---|
| Idun Peptides | 10/10 | Kovera Labs (named in certificate captions only) | $34.99 · 500mg · 5 Sep 2026 |
| MyPurePeptidepartner | 10/10 | Janoshik Analytical | $35.00 · 500mg · 10 Oct 2026 |
| Oneday Compoundspartner | 10/10 | ILS Laboratories (San Diego, CA) | $35.99 · 500mg · 29 Oct 2026 |
| Panda Peptides | 10/10 | Janoshik Analytical · ILS Labs (per batch) | $38.39 · 500mg · 25 Oct 2026 |
| Peptide Giantspartner | 10/10 | Janoshik Analytical · Vanguard Laboratory | $19.99 · 100mg · 15 Oct 2026 |
Top 5 by rubric score; 55 more on the ranking page.
NAD+ certificates we have opened
1 certificate for NAD+ in the COA library: 1 checkable on the laboratory's own site, 1 stating measured mass against the label, 1 carrying a flag.
- Oath Research· 1000mg · lot D3226057 · Freedom Diagnostics Accession 2609210281 (search code Oath2609210281)· 99.98% purity· 109% of labelverify at Freedom Diagnostics One vial measured
Side-effect questions
Side-effect section last reviewed 2026-09-12. Moved from the standalone side-effects page on 10 October 2026; text unchanged.
Everything we publish on NAD+
More on NAD+: comparisons, interactions, where to buy
Supporting Research
Moderate EvidenceModerate — for precursors raising NAD+ levels; Weak for IV/injectable or clinical outcomes
Evidence note: Human evidence supports NAD+ precursors (NMN, NR) raising blood NAD+ levels; this does not establish clinical anti-aging or disease outcomes. Injectable/IV NAD+ efficacy is separately unestablished — the evidence for oral precursors does not transfer to IV formulations. Distinguish "raises NAD+ in blood" (shown for oral precursors) from "reverses aging or fixes disease" (not shown for any route).
Human evidence supports NAD+ precursors (nicotinamide riboside, NMN) raising blood NAD+ levels in healthy adults. This does not establish clinical anti-aging outcomes, which remain unproven. IV/injectable NAD+ efficacy is separately unestablished. Distinguish "raises NAD+ in blood" (shown) from "reverses aging / fixes disease" (not shown).
References
- Martens CR, et al.HUMAN RCT, crossoverOral NR supplementation raises blood NAD+ and is well tolerated in healthy middle-aged and older adults. Does not support clinical anti-aging outcomes or IV-NAD+ efficacy.
Research Databases
PubMedNature
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