This is a working overview of Nicotinamide, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-07-11 and is reviewed periodically as new material appears.
NAD+ is the oxidized form of nicotinamide adenine dinucleotide, a coenzyme built from two nucleotides joined by a phosphate linkage. One nucleotide carries adenine, and the other carries nicotinamide; the plus sign denotes a formal positive charge on the nicotinamide ring, not a free proton. In cells, NAD+ and its reduced partner NADH form a reversible redox pair. That pair participates in electron transfer reactions throughout metabolism. The abbreviation NAD+ is common in biochemistry, while NAD(H) sometimes denotes the combined pool.
The molecule was first described in the early twentieth century as a factor that promoted fermentation in yeast extracts. Later work linked it to hydrogen transfer and to the oxidation of nutrients in living tissues. Its structure was resolved as a dinucleotide, which explained why it could accept and donate electrons at specific enzyme sites. Today, NAD+ is recognized as a central substrate and signaling precursor, not merely a metabolic cofactor. Whether all observed NAD+ changes reflect causal signaling remains an open question.
Beyond redox catalysis, NAD+ is a substrate for enzymes that transfer ADP-ribose or remove acetyl groups from proteins. Sirtuins and poly(ADP-ribose) polymerases consume NAD+ and release nicotinamide as a byproduct. These reactions connect cellular energy status to gene regulation, DNA repair, and stress responses. Because NAD+ is used rather than merely recycled in such signaling, its concentration reflects both biosynthesis and consumption. The balance between salvage and de novo synthesis pathways determines available pools in different tissues.
Biosynthesis of NAD+ starts from nicotinamide, nicotinic acid, or nicotinamide riboside through salvage pathways. A rate-limiting enzyme, nicotinamide phosphoribosyltransferase, converts nicotinamide to nicotinamide mononucleotide. Further coupling with ATP yields NAD+. In mammals, the liver and muscle can synthesize NAD+ from dietary precursors, but tissue levels vary widely. Researchers study these pathways to understand age-related changes, metabolic disorders, and neurodegeneration. Direct causal links between NAD+ decline and disease remain an active area of investigation.
| Property | Value | Notes |
|---|---|---|
| Chemical name | Nicotinamide adenine dinucleotide (oxidized form) | NAD+ denotes the oxidized redox state |
| Common synonyms | Diphosphopyridine nucleotide; coenzyme I | Older names appear in historical literature |
| Molar mass | About 663.43 g/mol | Free acid value; salts and hydrates differ |
| Appearance | White to off-white powder | The purified solid is white; solutions are clear |
| Solubility | Highly soluble in water | Aqueous buffers are common laboratory solvents |
Nicotinamide adenine dinucleotide, abbreviated NAD+, is a dinucleotide composed of two nucleotides joined by phosphate groups. One nucleotide contains adenine; the other contains nicotinamide. The molecule exists in oxidized (NAD+) and reduced (NADH) forms, and the reversible hydride transfer between them underlies many metabolic oxidation-reduction reactions. In cells, NAD+ serves as an electron acceptor in pathways such as glycolysis, the citric acid cycle, and oxidative phosphorylation. Its concentration and redox ratio vary by compartment, tissue, and metabolic state.
Beyond redox chemistry, NAD+ is consumed as a substrate by enzymes that transfer ADP-ribose or remove acetyl groups. Sirtuins use NAD+ in deacylation reactions, poly(ADP-ribose) polymerases use it in DNA damage responses, and CD38 hydrolases convert it to signaling metabolites. Because these enzymes compete for the same pool, changes in NAD+ availability can influence multiple cellular processes. The relative contribution of each consumption route differs by cell type and condition, and precise quantitative links remain an active area of study.
Research on NAD+ spans biochemistry, aging biology, and metabolism. Studies often examine how NAD+ levels change with age, diet, exercise, or disease states, and whether precursor supplementation alters those levels. Findings in animal models do not automatically translate to humans, and measurement methods vary across studies. Questions about tissue-specific effects, long-term consequences, and causal relationships remain open. NAD+ itself is not established as a single therapeutic agent with a broad clinical role.
In aqueous solution, NAD+ is most stable under mildly acidic to neutral conditions and degrades faster at high pH or elevated temperature. The molecule can hydrolyze at the pyrophosphate bond or undergo nonenzymatic cyclization. Buffers, chelating agents, and cold temperatures slow these losses during analysis. Repeated freeze-thaw cycles are generally avoided because they can promote degradation and concentration changes. Light exposure is also controlled, though NAD+ is less photolabile than some related nucleotides.
Commercial NAD+ is supplied as a solid, often as the free acid or a salt, and purity is verified by chromatographic methods. Laboratories typically store it desiccated at minus 20 degrees Celsius or below. Working solutions are prepared fresh because even sterile aqueous solutions can lose activity over hours to days depending on pH and temperature. Documentation may include a certificate of analysis, an assay value, and a recommended retest date. Researchers should verify identity and purity when results depend on precise cofactor concentrations.
NAD+ is commonly measured by high-performance liquid chromatography with ultraviolet detection, often at 254 or 260 nm. Enzymatic cycling assays provide higher sensitivity by coupling NAD+ to a reporter reaction. Mass spectrometry can distinguish NAD+ from close analogues and confirm isotope labeling. Sample preparation usually involves rapid quenching of metabolism to prevent interconversion with NADH. Because NAD+ and NADH differ by one hydride, extraction conditions strongly affect the measured ratio.
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=== Discontinued === Balovaptan (RG-7314, RO-5028442, RO-5285119) – vasopressin V1A receptor antagonist Blarcamesine (AE-37, ANA001, ANAVEX 2-73) – sigma σ1, muscarinic acetylcholine M1, and ionotropic glutamate NMDA receptor agonist Brilaroxazine (RP-5063, RP-5000) – dopamine D2, D3, D4 receptor partial agonist, serotonin 5-HT1A receptor agonist, serotonin 5-HT2A, 5-HT2B, 5-HT7 receptor antagonist, and atypical antipsychotic Bumetanide oral liquid (S-95008) – sodium–potassium–chloride symporter/cotransporter inhibitor and indirect GABAergic inhibitor discontinued after failed phase 3 trial Carbetocin (CYP-2001) – oxytocin receptor agonist CX-516 (1-BCP; BDP-12, SPD-420; AMPAlex) – AMPA receptor modulator EM-036 (memantine analogue) – ionotropic glutamate NMDA receptor antagonist, other actions Fasoracetam (AEVI-001, LAM-105, MDGN-001, NFC-1, NS-105) – various actions and racetam Fluoxetine rapid-dissolve (AT-001; AT001; NPL-2008; Serelsa; Zydis™ ODT fluoxetine) – serotonin reuptake inhibitor GTS-21 (DMXB-A, DMXB-A sustained release, DMXB-A-SR) – α7 nicotinic acetylcholine receptor partial agonist Ketamine intranasal (RVT-701) – ionotropic glutamate NMDA receptor antagonist Memantine (Namenda) – ionotropic glutamate NMDA receptor antagonist, other actions Oxytocin intranasal (Syntocinon Nasal Spray; TUR 001) – oxytocin receptor agonist Research programme: AMPA receptor agonists (ampakines, AMPAkines; CX compounds) - RespireRx – ionotropic glutamate AMPA receptor agonists Research programme: NMDA receptor modulators - AbbVie/Naurex (NRX-1050; NRX-1051; NRX-1059; NRX-105x; NRX-1060; NRX-2085; NRX-20xx) – ionotropic glutamate NMDA receptor modulators Risperidone extended-release (Risperisphere) – dopamine D2 and D3 receptor antagonist, serotonin 5-HT1B, 5-HT2A, 5-HT2C, and 5-HT7 receptor antagonist or inverse agonist, α1- and α2-adrenergic receptor antagonist, histamine H1 receptor inverse agonist, and atypical antipsychotic Secretin (INN-329, RG-1068; SecreFlo) – medical imaging enhancer (diagnosis) Suramin (Antrypol) – DNA-directed DNA polymerase inhibitor and intercellular signaling peptide/protein inhibitor Trichuris suis ova (CNDO-201, TSO, TSO-2500, TSO-7500) – immunomodulator Trofinetide (Daybue; G-2Me-PE; Glycyl-2-methyl-L-prolyl-L-glutamic acid; NNZ-2566; IGF-1 (1–3) analogue) – unknown / various actions
=== Other concerns === A potentially significant problem following bisulfite treatment is incomplete desulfonation of pyrimidine residues due to inadequate alkalization of the solution. This may inhibit some DNA polymerases, rendering subsequent PCR difficult. However, this situation can be avoided by monitoring the pH of the solution to ensure that desulfonation will be complete. A final concern is that bisulfite treatment greatly reduces the level of complexity in the sample, which can be problematic if multiple PCR reactions are to be performed (2006). Primer design is more difficult, and inappropriate cross-hybridization is more frequent.
=== Advantages === In the early 1970s, the Alza Corporation, through their founder Alejandro Zaffaroni, filed the first US patents describing transdermal delivery systems for scopolamine, nitroglycerin and nicotine. People found that applying medicines on the body surfaces is beneficial in many aspects. Skin medicines can give faster onset and local effect on our body as the surface cream can bypass first pass metabolism such as hepatic and intestinal metabolism. Apart from the absorption, dermal drugs effectively prevent oral delivery limitations such as nausea and vomiting and poor appliances due to unpalatable tastes of the drugs . Topical application is an easy way for patients to tackle skin infections in a painless and non-invasive way. From a patient perspective, applying drugs on skin also provides stable dosage in blood so as to give the optimal bioavailability and therapeutic effects. In case of overdose or unwanted side effects, patients can take off or wash out the medicines quickly to eliminate toxicity by simply removing the patch to stop the delivery of drugs.
Sources: en.wikipedia.org
Polymer oxidation has caused accidents involving medical devices. One of the oldest known failure modes is ozone cracking caused by chain scission when ozone gas attacks susceptible elastomers, such as natural rubber and nitrile rubber. They possess double bonds in their repeat units which are cleaved during ozonolysis. Cracks in fuel lines can penetrate the bore of the tube and cause fuel leakage. If cracking occurs in the engine compartment, electric sparks can ignite the gasoline and can cause a serious fire. In medical use degradation of polymers can lead to changes of physical and chemical characteristics of implantable devices. Nylon 66 is susceptible to acid hydrolysis, and in one accident, a fractured fuel line led to a spillage of diesel into the road. If diesel fuel leaks onto the road, accidents to following cars can be caused by the slippery nature of the deposit, which is like black ice. Furthermore, the asphalt concrete road surface will suffer damage as a result of the diesel fuel dissolving the asphaltenes from the composite material, this resulting in the degradation of the asphalt surface and structural integrity of the road.
=== Women === In 2021, the World Economic Forum ranked Belize 90th out of 156 countries in its Global Gender Gap Report. Of all the countries in Latin America and the Caribbean, Belize ranked fourth from last. It ranked higher in the categories of "economic participation and opportunity" and "health and survival", but very low in "political empowerment". In 2019, the UN gave Belize a Gender Inequality Index score of 0.415, ranking it 97th out of 162 countries. As of 2019, 49.9% of women in Belize participate in the workforce, compared to 80.6% of men. 11.1% of the seats in Belize's National Assembly are filled by women.
=== Antibacterial immune factor === Researchers have isolated a powerful antibacterial peptide, VK25, from the blood plasma of Komodo dragons. Based on their analysis of this peptide, they have synthesized a short peptide dubbed DRGN-1 and tested it against multidrug-resistant (MDR) pathogens. Preliminary results of these tests show that DRGN-1 is effective in killing drug-resistant bacterial strains and even some fungi. It has the added observed benefit of significantly promoting wound healing in both uninfected and mixed biofilm infected wounds.
Sources: en.wikipedia.org
It indicates a formal positive charge on the nicotinamide ring. The molecule is not simply a protonated acid, and the charge is part of its redox chemistry.
NAD+ is the oxidized form, while NADH is the reduced form carrying two additional electrons and a proton. The two forms interconvert in many metabolic reactions.
No. NADP+ contains an extra phosphate group on the adenine ribose. NADP+ and NADPH tend to participate in different biosynthetic and antioxidant pathways.
NAD+ is the oxidized form and NADH is the reduced form of the same coenzyme. NAD+ accepts electrons during oxidation reactions, becoming NADH, which can donate electrons in other reactions. The ratio between them helps describe a cell's redox state.