NAD+
Cellular coenzyme (dinucleotide)
A coenzyme studied extensively in cellular-energy and longevity research.
Overview
Nicotinamide adenine dinucleotide (NAD+) is a naturally occurring coenzyme present in all living cells, first described in the early 20th century in the context of fermentation and cellular respiration. It is not a peptide but a dinucleotide composed of a nicotinamide moiety and an adenine moiety joined through ribose and phosphate groups.
At a glance
What NAD+ does
NAD+ (nicotinamide adenine dinucleotide) is a central redox coenzyme rather than a signaling peptide, and what it "does" is enable the chemistry that keeps cells energetically alive. In its oxidized (NAD+) and reduced (NADH) forms it shuttles electrons through glycolysis, the TCA cycle, fatty-acid oxidation, and oxidative phosphorylation, making it indispensable for ATP production in mitochondria. Because it accepts and donates a hydride, the NAD+/NADH ratio also sets the cell's overall redox tone, which feeds back on metabolic flux.
Beyond metabolism, NAD+ is consumed as a substrate by three enzyme families that link it to aging biology: sirtuins (NAD+-dependent deacylases such as SIRT1/SIRT3 that regulate gene silencing, mitochondrial biogenesis and stress resistance), PARPs (which use NAD+ to build poly-ADP-ribose chains during DNA-damage repair), and the ectoenzyme CD38 (a major NAD+ hydrolase). Each cleaves NAD+ to run its reaction, so NAD+ availability directly gates sirtuin activity and DNA-repair capacity.
The aging rationale is that tissue NAD+ declines with age, partly driven by rising CD38 activity and DNA-damage-driven PARP consumption, which is associated with impaired mitochondrial and nuclear function. Preclinical work shows that restoring NAD+ with precursors (NMN, NR) can raise sirtuin activity and improve metabolic and mitochondrial measures in aged rodents. Human trials confirm oral precursors reliably raise blood NAD+ levels, but robust clinical proof that this reverses aging endpoints in people is still limited and ongoing.
Effects reported in research
- Serves as the obligate electron carrier (NAD+/NADH) for glycolysis, the TCA cycle, and oxidative phosphorylation, directly enabling mitochondrial ATP synthesis.
- Acts as the required co-substrate for sirtuin (SIRT1-7) deacetylation reactions, so its availability gates sirtuin-driven mitochondrial biogenesis and stress-resistance programs.
- Supplies the ADP-ribose units that PARP enzymes polymerize during DNA single- and double-strand-break repair, linking NAD+ pools to genome maintenance.
- Is hydrolyzed by CD38, whose rising activity with age is a demonstrated driver of NAD+ decline in preclinical models.
- Restoration via NMN/NR precursors improved insulin sensitivity, mitochondrial function, and physical measures in aged-rodent studies (preclinical).
- Oral NAD+ precursors (NR, NMN) have been shown in human trials to reliably and dose-dependently raise whole-blood NAD+ levels.
- The NAD+/NADH redox ratio sets cellular redox balance, influencing metabolic enzyme flux and, in models, cellular senescence markers (preclinical).
- Clinical evidence that raising NAD+ translates into measurable anti-aging or disease-modifying outcomes in humans remains limited and inconsistent.
Effects listed reflect findings reported in the research literature — many in animal or in-vitro models. Listing an effect is not a claim of efficacy or a therapeutic indication in humans.
Mechanism of action
NAD+ functions as a central redox cofactor, cycling between its oxidized (NAD+) and reduced (NADH) forms to shuttle electrons in glycolysis, the citric acid cycle, and oxidative phosphorylation. Beyond redox chemistry, NAD+ is a required substrate for enzymes that consume it, including sirtuins (NAD+-dependent deacylases), poly(ADP-ribose) polymerases (PARPs) involved in DNA repair, and CD38. Cellular NAD+ levels have been reported to decline with age in various tissues, which is a focus of aging research. It is synthesized de novo from tryptophan and through salvage pathways from precursors such as nicotinamide, nicotinic acid, and nicotinamide riboside.
Mechanistic description reflects published research-literature understanding. Much peptide research is preclinical (in-vitro or animal-model); mechanism in humans may differ and is not established for many compounds.
What it's studied for
Research contexts in which NAD+ appears in the literature. Listing a research area is not a claim of efficacy or a therapeutic indication.
Key characteristics
- NAD+ is a coenzyme/dinucleotide, not a peptide; PeptiDex includes it as an adjacent research molecule
- Acts as a core redox carrier (NAD+/NADH) in energy metabolism
- Serves as a consumed substrate for sirtuins, PARPs, and CD38
- Tissue NAD+ levels have been reported to decline with age in research settings
- Studied largely through precursors (nicotinamide riboside, NMN) that raise NAD+ pools
- Much of the longevity-related evidence is preclinical
Reported research dosing reference only
Educational reference, not dosing guidance. The figures below summarize amounts reported in published research and research-community protocols, provided for educational and research context only. They are not medical advice, not a recommendation, and not instructions for human use. NAD+ is a research compound.
Reported research and clinical-adjacent protocols describe intravenous or subcutaneous NAD+ across a wide range, with slow administration to minimize reported side effects. These are reference figures for research context only, not dosing guidance for humans.
- Subcutaneous research reference: commonly cited 20-100 mg per administration, titrated up gradually
- IV infusion research reference: 250-750 mg per session cited in clinical-adjacent literature, infused slowly over hours
- Loading-phase references sometimes cite 100-200 mg/day before stepping down to intermittent frequency
No approved dose or regimen exists; rapid administration is associated with reported flushing/chest discomfort, so slow delivery is emphasized. NAD+ is a coenzyme, not a peptide.
How it compares
Unlike the peptides in this category, NAD+ is a small-molecule coenzyme central to redox metabolism rather than a signaling peptide, and it is studied primarily via precursor supplementation.
Commonly studied alongside
Compounds frequently researched together with NAD+ in the literature. Cross-referenced for research context — not a usage or combination recommendation.
Handling & Stability
Lyophilized peptides are stored cold, protected from light, and reconstituted only at the time of intended in-vitro work.
- Avoid repeated freeze-thaw cycles
- Verify supplier lot and Certificate of Analysis
- Follow institutional lab-safety protocols
Analytical & COA Concepts
Reputable research suppliers publish a third-party Certificate of Analysis per batch. Key analytical concepts referenced in COAs include:
Category Context
NAD+ sits in the Longevity & Cellular area of the PeptiDex library.
- Entry type: Research compound reference
- Browse the full library →
- Glossary of terms →
Where researchers source NAD+
For researchers studying NAD+, third-party suppliers such as Practically Natty Peptides offer research-grade material with third-party Certificates of Analysis and US-based shipping.
View research-supplier listing →
Outbound link to a third-party research supplier. Inclusion does not constitute endorsement; all editorial content is developed independently.
Frequently asked questions
What is NAD+ and what is it studied for?
NAD+ (nicotinamide adenine dinucleotide) is a coenzyme central to cellular energy metabolism, redox reactions, and as a substrate for sirtuins and PARP enzymes involved in DNA repair. It is studied in models of aging, mitochondrial function, metabolic decline, and neuroprotection, where tissue NAD+ levels fall with age. It is a naturally occurring coenzyme, not a peptide.
Is NAD+ a peptide?
No. NAD+ is a dinucleotide coenzyme composed of two nucleotides (one bearing adenine, the other nicotinamide) joined through phosphate groups, not a chain of amino acids. It is grouped in longevity research catalogs alongside peptides because of its role in aging and mitochondrial studies, but it is a distinct chemical class.
How does NAD+ differ from precursors like NMN and NR?
NMN (nicotinamide mononucleotide) and NR (nicotinamide riboside) are biosynthetic precursors that cells convert into NAD+, whereas NAD+ is the finished coenzyme. Precursors are commonly studied as oral routes to raise intracellular NAD+, while NAD+ itself is studied via IV or subcutaneous routes in research settings. Direct cellular uptake of intact NAD+ is a subject of ongoing research.
What does NAD+ research say about administration route?
Research and clinical-adjacent literature most commonly describe intravenous infusion and subcutaneous injection for NAD+, since oral bioavailability of the intact molecule is limited. IV protocols are typically slow infusions to reduce reported flushing and discomfort. These are research-context observations, not human-use guidance.
Why is NAD+ associated with aging?
Cellular NAD+ concentrations decline with age across many tissues, which is hypothesized to impair sirtuin activity, mitochondrial function, and DNA-repair capacity. This decline is a core rationale for studying NAD+ and its precursors in longevity and metabolic research. Whether restoring NAD+ reverses age-related outcomes in humans remains under investigation.
Answers are educational summaries of research-literature context and do not constitute medical advice. See the Research Library, COA guide, and Storage & Handling guide for more.