What Is NAD+?
Nicotinamide adenine dinucleotide (NAD+) is a coenzyme found in all living cells. It plays a central role in cellular energy metabolism, DNA repair, and gene expression regulation, and has become one of the most studied molecules in longevity and metabolic biology over the past two decades. Unlike peptide-based research compounds, NAD+ is a small molecule coenzyme — but its biological importance and growing research literature place it among the most significant compounds in cellular research.
Molecular Properties
- Full name: Nicotinamide adenine dinucleotide (oxidised form)
- Molecular formula: C₂₁H₂₇N₇O₁₄P₂
- Molecular weight: 663.4 Da
- Forms: NAD+ (oxidised), NADH (reduced); NAD+ is the research-relevant, biologically active form
- Biosynthesis: from tryptophan (de novo), nicotinamide (salvage pathway), or nicotinamide riboside/NMN (precursor routes)
Primary Mechanism: Redox Cofactor in Energy Metabolism
NAD+ functions as an electron carrier in oxidation-reduction (redox) reactions central to cellular energy production. In its oxidised form (NAD+), it accepts electrons from metabolic substrates; in its reduced form (NADH), it donates electrons to the mitochondrial electron transport chain, driving ATP synthesis.
Key metabolic reactions dependent on NAD+/NADH cycling:
- Glycolysis: NAD+ is required for glyceraldehyde-3-phosphate dehydrogenase (GAPDH) activity
- TCA cycle (Krebs cycle): Multiple NAD+-dependent dehydrogenases — isocitrate dehydrogenase, alpha-ketoglutarate dehydrogenase, malate dehydrogenase
- Beta-oxidation: NAD+ participates in fatty acid catabolism in mitochondria
- Oxidative phosphorylation: NADH feeds Complex I of the electron transport chain, generating the proton gradient driving ATP synthase
Sirtuin Activation and Epigenetic Regulation
Beyond its role as a redox cofactor, NAD+ functions as a mandatory substrate for sirtuins (SIRT1–7) — a family of NAD+-dependent deacetylases and ADP-ribosyltransferases that regulate gene expression, metabolic homeostasis, and stress responses.
Key sirtuin-mediated processes in research models:
- SIRT1: Deacetylates p53, NF-κB, PGC-1α — regulating apoptosis, inflammation, and mitochondrial biogenesis
- SIRT3: Mitochondrial deacetylase; activates oxidative phosphorylation enzymes and modulates ROS production
- SIRT6: Involved in DNA double-strand break repair and telomere maintenance
Sirtuin activity is directly coupled to intracellular NAD+ concentrations — a relationship that has made NAD+ supplementation a central strategy in aging and metabolic disease research models. Imai et al. (2013, Cell Metabolism) demonstrated that declining NAD+ levels in aged murine muscle tissue were associated with reduced SIRT1 activity and impaired mitochondrial function, reversible through NAD+ precursor administration.
PARP Activation and DNA Repair
Poly(ADP-ribose) polymerases (PARPs) consume NAD+ as a substrate to synthesise poly(ADP-ribose) chains on target proteins in response to DNA damage. This process is central to the DNA damage response (DDR):
- PARP1 detects single- and double-strand DNA breaks and catalyses PAR chain synthesis, recruiting DNA repair machinery
- Intense PARP1 activation following genotoxic stress can deplete intracellular NAD+ stores, triggering cell death pathways
- The NAD+–PARP axis is a major area of research in cancer biology, with PARP inhibitors now in clinical use
CD38 and NAD+ Decline
CD38, an NAD+-consuming ectoenzyme expressed on immune cells and other tissues, has emerged as a key regulator of systemic NAD+ levels. Camacho-Pereira et al. (2016, Cell Metabolism) demonstrated that CD38 activity increases with age, contributing to age-associated NAD+ decline. This finding has positioned CD38 as a target in research models exploring NAD+ homeostasis and healthy aging biology.
Key Research Areas
Longevity and aging research: NAD+ levels decline with age across multiple tissues. Research in model organisms has examined whether restoring NAD+ levels via direct supplementation or precursors (NMN, NR) can reverse age-associated functional decline.
Metabolic disease models: NAD+ plays a central role in insulin sensitivity, fatty acid oxidation, and glucose metabolism. Preclinical models have examined NAD+ restoration in the context of diet-induced obesity and type 2 diabetes models.
Neuroprotection: SIRT1 and SIRT3 activation via NAD+ has been studied in neurodegeneration models, with particular interest in mitochondrial protection and axonal integrity.
Cancer biology: The NAD+–PARP axis, CD38 expression, and the Warburg effect all intersect with NAD+ metabolism, making it a significant research target in oncology models.
Sourcing NAD+ for Research
R&D Peptides supplies NAD+ in two concentrations for research applications: NAD+ 500mg and 1000mg, each supplied with a batch-specific Certificate of Analysis. Both are supplied strictly for in vitro research use only.
For quality and testing standards, see our quality and testing page, or browse our full Longevity & Anti-Ageing research compound range.
All content on this page is for educational and informational purposes only. NAD+ is supplied by R&D Peptides strictly for in vitro research use. It is not intended for human or veterinary administration, and no therapeutic claims are made or implied.
