What is NAD+?

Nicotinamide adenine dinucleotide (NAD+) is a dinucleotide cofactor present in every living cell, formed from an adenine nucleotide joined to a nicotinamide nucleotide through their phosphate groups. It cycles between oxidized (NAD+) and reduced (NADH) states and is the primary electron carrier in central carbon metabolism.

PX1 Research supplies high-purity lyophilized NAD+ for in-vitro biochemical assay work, enzyme kinetics and mitochondrial research where cofactor purity directly determines assay signal quality.

Biochemical role

Beyond redox chemistry, NAD+ is consumed as a substrate by three enzyme families: sirtuins (NAD+-dependent deacylases), poly-ADP-ribose polymerases involved in DNA damage response, and CD38/CD157 ectoenzymes. These consuming reactions link cellular NAD+ availability to transcriptional regulation, genome maintenance and calcium signaling.

Cellular NAD+ concentrations decline with age in many model organisms, which is why NAD+ and its precursors — nicotinamide riboside and nicotinamide mononucleotide — appear so widely in current longevity research.

Laboratory handling and storage

NAD+ ships as a lyophilized powder in a sealed, tamper-evident vial. Store the unopened vial between −20°C and −80°C, protected from light, until the day of use. In this state the peptide is stable through the labeled expiration date printed on the lot documentation.

Purity, testing and Certificate of Analysis

Every PX1 Research lot of NAD+ is manufactured in the United States and released against a documented specification of ≥99% purity by reversed-phase HPLC, with identity confirmed on the same lot by high-resolution LC-MS against the theoretical mass of the sequence.

Research use only

NAD+ supplied by PX1 Research is intended strictly for in-vitro laboratory and research applications. It is not a drug, food, cosmetic, or medical device, and it is not for human or veterinary use, diagnosis, treatment, or consumption.

Researchers are responsible for handling the compound in accordance with their institution's safety procedures and all applicable local regulations. Safety data sheets and current lot documentation are available on this site.

Purity, identity and certificate of analysis

NAD+ (nicotinamide adenine dinucleotide) is not a peptide but a dinucleotide coenzyme, and its analytical requirements differ accordingly. Purity is determined by reversed-phase HPLC with UV detection at 260 nm, where the adenine chromophore absorbs strongly, and the method must resolve NAD+ from nicotinamide mononucleotide, nicotinamide and ADP-ribose — the degradation and precursor species that a coarse gradient reports as a single front peak.

Identity is confirmed by mass spectrometry against the theoretical mass of the oxidized dinucleotide. The oxidized and reduced forms, NAD+ and NADH, differ in both mass and spectral behavior, and a lot in which a fraction has reduced is a different test article for enzymology even though the nominal name is unchanged.

Each lot carries endotoxin by kinetic chromogenic LAL, residual solvents by gas chromatography and water content by Karl Fischer titration. Water content is particularly relevant for this compound because the lyophilized powder is hygroscopic and adsorbed moisture both inflates the apparent mass and accelerates hydrolysis of the pyrophosphate linkage.

How NAD+ relates to NMN, NR and MOTS-c

NMN (nicotinamide mononucleotide) and NR (nicotinamide riboside) are biosynthetic precursors within the salvage pathway that converges on NAD+. Studies comparing them address pathway entry point and cellular uptake rather than the coenzyme's own chemistry, so a design intending to supply the coenzyme directly and one intending to supply a precursor are answering different questions.

MOTS-c is a mitochondrially encoded peptide described in the literature in connection with metabolic and retrograde signaling, and it appears alongside NAD+ in mitochondrial-function work. The two are mechanistically unrelated at the molecular level — one is a coenzyme consumed by enzymatic reactions, the other a signaling peptide — and pairing them in a study design reflects a shared research area, not a shared mechanism.

Because NAD+ is a substrate for sirtuins, PARPs and CD38 as well as for classical redox enzymes, in-vitro work using it typically has to state which enzyme class is under study. The same vial serves very different assays, and the appropriate purity check — resolving NMN and nicotinamide, or resolving NADH — depends on which one.

Common research questions about NAD+

Is NAD+ a peptide? No. It is a dinucleotide coenzyme, which is why its certificate reports UV-based purity at 260 nm and mass confirmation of the oxidized dinucleotide rather than peptide-specific parameters such as sequence-related truncation impurities.

How does NAD+ differ from NMN and NR? NMN and NR are precursors that enter the salvage pathway upstream; NAD+ is the coenzyme itself. Substituting one for another changes the research question, not just the material.

Why is NAD+ solution so short-lived? Its pyrophosphate and nicotinamide-ribose linkages are hydrolytically labile at alkaline and acidic pH respectively, and the degradation products are biologically active in their own right. Aged solutions therefore drift in composition rather than simply losing potency.

What should a NAD+ certificate show? A chromatogram on a method that visibly resolves NMN, nicotinamide and ADP-ribose from the parent peak, mass confirmation of the oxidized form, water content by Karl Fischer, endotoxin by LAL and residual solvents by gas chromatography — all for the specific lot in the vial.