The short version of Nicotinamide fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-01-25 and is reviewed periodically as new material appears.
NAD+ is a dinucleotide composed of two nucleotides joined by a pyrophosphate linkage. One nucleotide contains adenine, and the other contains nicotinamide. The oxidized form carries a positive charge on the nicotinamide ring and is abbreviated NAD+. It functions as a cofactor in hydride-transfer reactions, accepting electrons in catabolic pathways. In cells, it interconverts with reduced NADH, forming a redox couple central to energy metabolism. The molecule is water-soluble and does not cross cell membranes freely without specific transport or precursor pathways.
The nicotinamide ring undergoes reversible reduction at the para position, converting NAD+ to NADH. This reaction transfers a hydride equivalent, not a free hydrogen atom or electron alone. Because the redox pair has a defined reduction potential, it links oxidation of fuels to respiratory chain activity. Many dehydrogenases use NAD+ as a co-substrate and produce NADH. The ratio of NAD+ to NADH reflects metabolic state and influences flux through several pathways.
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.
NAD+ is a dinucleotide composed of adenine, ribose, and nicotinamide groups joined by phosphate linkages. It serves as a coenzyme in oxidoreductase reactions, cycling between oxidized NAD+ and reduced NADH. The molecule is water-soluble and occurs in all living cells. Its nicotinamide ring accepts hydride ions during catabolic reactions, linking substrate oxidation to electron transport. This redox couple supports ATP production and helps maintain cytosolic and mitochondrial redox balance in many cell types.
| Property | Value | Notes |
|---|---|---|
| IUPAC name | Nicotinamide adenine dinucleotide | Oxidized dinucleotide form |
| CAS Registry Number | 53-84-9 | Common entry for beta-NAD+ |
| Molecular formula | C21H27N7O14P2 | Free acid form |
| Molar mass | 663.43 g/mol | Calculated for free acid |
| Water solubility | Freely soluble | Charged dinucleotide; less soluble in organic solvents |
Solid NAD+ is usually supplied as a white to off-white powder or lyophilized preparation. It is hygroscopic and should be kept desiccated at low temperature, commonly -20 °C or below for long-term storage. Aqueous solutions are less stable than dry material and are often prepared fresh or stored frozen in aliquots. Light exposure and repeated freeze-thaw cycles can promote degradation, so amber containers and single-use aliquots are preferred. Buffered solutions near neutral pH are generally less stable than acidic or frozen preparations.
Quantification of NAD+ in biological samples typically uses liquid chromatography coupled to mass spectrometry. Enzymatic cycling assays offer higher throughput and rely on NAD+ dependent dehydrogenases to amplify signal. Both approaches require careful sample quenching because NAD+ can be rapidly consumed or converted after collection. Acidic extraction is common for NAD+, while alkaline conditions favor NADH in some protocols. Isotopically labeled internal standards help correct for losses during extraction and ionization.
Commercial NAD+ is available at research grade, often with purity specifications determined by high-performance liquid chromatography. Certificates of analysis may report water content, residual solvents, and counterion identity. Identity can be confirmed by ultraviolet absorbance near 260 nm, mass spectrometry, or enzymatic activity. Because different salt forms and hydration states exist, researchers should verify that the product matches the intended molecular form. Lot-to-lot variation in purity can affect quantitative assays and should be documented.
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 redox reactions, NAD+ accepts a hydride ion, which consists of two electrons and one proton. The hydride adds to the nicotinamide ring at a specific carbon, converting NAD+ into NADH. Dehydrogenase enzymes use this step in glycolysis, the citric acid cycle, and fatty acid oxidation. NADH later donates electrons to the mitochondrial electron transport chain, helping to drive ATP synthesis. The balance between NAD+ and NADH reflects the metabolic state of a cell, and shifts in that balance can alter how pathways operate.
Beyond electron transfer, NAD+ serves as a substrate for enzymes that cleave it and attach its ADP-ribose portion to other molecules. This group includes poly(ADP-ribose) polymerases, CD38, and sirtuins. Such reactions consume NAD+ and can influence its availability for metabolism. Cells replenish NAD+ through a salvage pathway that recycles nicotinamide and through routes starting from tryptophan or vitamin B3 forms. How these synthesis and consumption routes are coordinated across tissues remains an active area of study, and compartment-specific concentrations are difficult to measure directly.
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.
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.
=== CHIP, Medicaid, and Medicare Coverage === In April 2025, the Trump Administration declined to finalize a Biden Administration proposal that would have required Medicare, Medicaid, and the Children's Health Insurance Program (CHIP) to broadly cover GLP-1 drugs for weight loss. In November 2025, the Trump Administration announced TrumpRx to lower the price of GLP-1 drugs to $245 per month for people covered by Medicare. Coverage for people with obesity and at least one comorbidity (elevated LDL-cholesterol, high blood pressure and/or MASLD) may be implemented as early as April 2026. The cost will be significantly higher because most insurance companies do not cover it in their formulary. Before this change, most people covered by Medicaid and CHIP paid $3 a month, the same as for brand-name medications. Starting in July 2026, eligible Medicare beneficiaries will gain access to certain weight-loss medications for $50 a month through a temporary initiative called the Medicare GLP-1 Bridge program. This pilot is designed to create a more affordable pathway for people who need these treatments while broader, long-term coverage options are being finalized.
== Disadvantages == The Bradford assay is linear over a short range, typically from 0 μg/mL to 2000 μg/mL, often making dilutions of a sample necessary before analysis. In making these dilutions, error in one dilution is compounded in further dilutions resulting in a linear relationship that may not always be accurate. Basic conditions and detergents, such as SDS, can interfere with the dye's ability to bind to the protein through its side chains. The reagents in this method tend to stain the test tubes. Same test tubes cannot be used since the stain would affect the absorbance reading. This method is also time sensitive. When more than one solution is tested, it is important to make sure every sample is incubated for the same amount of time for accurate comparison. A limiting factor in using Coomassie-based protein determination dyes stems from the significant variation in color yield observed across different proteins This limiting factor is notably evident in collagen-rich protein samples, like pancreatic extracts, where both the Lowry and Bradford methods tend to underestimate protein content. It is also inhibited by the presence of detergents, although this problem can be alleviated by the addition of cyclodextrins to the assay mixture. Much of the non-linearity stems from the equilibrium between two different forms of the dye which is perturbed by adding the protein. The Bradford assay linearizes by measuring the ratio of the absorbances, 595 over 450 nm. This modified Bradford assay is approximately 10 times more sensitive than the conventional one.
=== Obsessive–compulsive disorder === Fluoxetine is effective in the treatment of obsessive–compulsive disorder (OCD). It is effective for treating OCD in children, adolescents and adults. The American Academy of Child and Adolescent Psychiatry state that SSRIs, including fluoxetine, should be used as first-line therapy in children, along with cognitive behavioral therapy (CBT), for the treatment of moderate to severe OCD.
On 14 December 1895, there was a large outbreak of botulism in the Belgian village of Ellezelles that occurred at a funeral where people ate pickled and smoked ham; three of them died. By examining the contaminated ham and performing autopsies on the people who died after eating it, van Ermengem isolated an anaerobic microorganism that he called Bacillus botulinus. He also performed experiments on animals with ham extracts, isolated bacterial cultures, and toxins extracts from the bacteria. From these he concluded that the bacteria themselves do not cause foodborne botulism, but rather produce a toxin that causes the disease when ingested. As a result of Kerner's and van Ermengem's research, it was thought that only contaminated meat or fish could cause botulism. This idea was refuted in 1904 when a botulism outbreak occurred in Darmstadt, Germany, because of canned white beans. In 1910, the German microbiologist J. Leuchs published a paper showing that different strains of Bacillus botulinus caused the outbreaks in Ellezelles and Darmstad and that the toxins were serologically distinct. In 1917, Bacillus botulinus was renamed Clostridium botulinum, as it was decided that the term Bacillus should refer to a group of aerobic microorganisms, while Clostridium would be used only to describe a group of anaerobic microorganisms. In 1919, Georgina Burke used toxin-antitoxin reactions to identify two strains of Clostridium botulinum, which she designated A and B.
Sources: en.wikipedia.org
Calotropis is a genus of flowering plants in the family Apocynaceae, first described as a genus in 1810. It is native to southern Asia and North Africa. They are commonly known as milkweeds because of the latex they produce. Calotropis species are considered common weeds in some parts of the world. The flowers are fragrant and are often used in making floral tassels in some mainland Southeast Asian cultures. Fibers of these plants are called mudar or mader. Calotropis species are usually found in abandoned farmland.
November 11, 1990 – The Socialist Republic of Macedonia within Yugoslavia holds its first multi-party elections. November 18, 1990 – The Socialist Republic of Bosnia and Herzegovina within Yugoslavia holds its first multiparty elections. November 19, 1990 – NATO and Warsaw Pact sign the Treaty on Conventional Armed Forces in Europe. November 28, 1990 – Margaret Thatcher falls from power as UK Prime Minister; John Major takes office. December 9, 1990 – The Socialist Republic of Montenegro within Yugoslavia holds its first multi-party elections. December 9–23, 1990 – The Socialist Republic of Serbia within Yugoslavia holds its first multi-party elections. December 22, 1990 – Lech Wałęsa becomes president of Poland; Polish government-in-exile ends. December 23, 1990 – Slovenia holds an independence referendum resulting in a majority of Slovenians voting in favour of Slovenia seeking independence from Yugoslavia.
=== Reactivity === Metallic elements which are more electropositive than hydrogen, particularly the alkali metals and, to a lesser extent, alkaline earth metals, displace hydrogen from water, forming hydroxides and releasing hydrogen. At high temperatures, coke, a form of carbon, reacts with steam to form carbon monoxide and hydrogen.
Sources: en.wikipedia.org
NAD+ is the oxidized form, while NADH is the reduced form carrying an added hydride. The two form a redox pair that cells use in many energy-yielding reactions.
NAD+ is a small organic cofactor, not a protein or enzyme. It binds temporarily to enzymes such as dehydrogenases to assist electron transfer.
Intact NAD+ is generally not taken up efficiently by most cells because it is charged and water-soluble. Cells often rely on precursors such as nicotinamide or nicotinamide riboside to produce NAD+ internally.
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.