Everything below concerns quality control. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
Biosynthesis occurs through salvage, Preiss-Handler, and de novo pathways. In mammals, the salvage pathway from nicotinamide predominates, and NAMPT is often described as rate-limiting. Nicotinamide riboside and nicotinic acid enter related routes that converge on NAD+ production. Tissue NAD+ concentrations vary widely and are maintained by a balance of synthesis and consumption. Some studies report age-related declines in certain tissues, but whether these changes cause disease or can be reversed to improve human health remains an open question.
NAD+ stands for nicotinamide adenine dinucleotide, the oxidized form of a coenzyme found in all living cells. The molecule consists of two nucleotides, adenine and nicotinamide ribose, joined through phosphate groups. Its chemical formula is C21H27N7O14P2, and the free acid has a molar mass near 663.43 grams per mole. In redox reactions, NAD+ accepts a hydride ion and becomes NADH. The pair NAD+ and NADH participates in hundreds of metabolic reactions, including steps in glycolysis, the citric acid cycle, and oxidative phosphorylation.
Research on NAD+ often examines changes with age, diet, exercise, and disease states, but causal relationships are difficult to establish. Some studies measure NAD+ levels, while others assess enzyme activity or downstream markers. In the literature, terms such as "NAD+ decline" and "NAD+ boosting" appear in both scientific and commercial contexts, sometimes without precise definitions. Whether changes in measured NAD+ directly produce health effects remains an open question. Results from cells, animals, and humans cannot be assumed to translate directly.
Measuring NAD+ in biological samples requires rapid processing because the compound can degrade or interconvert after collection. Common approaches include enzymatic cycling assays, high-performance liquid chromatography, and mass spectrometry. Each method has different sensitivity, specificity, and susceptibility to interference from related nucleotides. Sample type matters: cultured cells, animal tissues, and human blood present distinct challenges. Reported values can vary widely across laboratories because of differences in extraction, normalization, and analytical platform. Standardization remains an open issue in the field.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C21H27N7O14P2 | Oxidized form; NADH adds a hydride equivalent. |
| Molar mass | 663.43 g/mol | Free acid form; salts have different values. |
| CAS Registry Number | 53-84-9 | Common identifier for beta-NAD. |
| Appearance | White to off-white powder | Hygroscopic; may absorb moisture from air. |
| Solubility | Freely soluble in water | Poorly soluble in most organic solvents. |
Laboratory handling of NAD+ follows standard practices for hygroscopic fine chemicals. Personnel typically avoid inhalation and skin contact, use gloves and eye protection, and work in a ventilated area. Quality control may include ultraviolet absorbance at the nicotinamide maximum, chromatographic purity, water content, and identity confirmation by mass spectrometry. Because commercial preparations can contain counterions, residual solvents, or related nucleotides, a certificate of analysis helps verify the material. Researchers should confirm that the form supplied matches the intended assay.
Measuring NAD+ in biological samples requires care because the molecule is chemically reactive and present at low concentrations in some tissues. Common approaches include enzymatic cycling assays, high-performance liquid chromatography, and liquid chromatography coupled to mass spectrometry. Each method has different sensitivity and specificity, and sample preparation can affect results. Acidic or alkaline extraction steps are used in some protocols, but the choice depends on the analyte and matrix. No single method is universally optimal for every tissue or fluid.
Solid NAD+ is relatively stable when kept dry, cold, and protected from light. Aqueous solutions are more vulnerable to hydrolysis and can lose activity during repeated freeze-thaw cycles or prolonged storage at ambient temperature. Stability depends on pH, ionic strength, and the presence of degrading enzymes or metal ions. For many laboratory uses, aliquots are stored frozen and thawed only once. Exact degradation rates vary by matrix, so stability should be checked for each application rather than assumed.
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.
NAD+ also serves as a substrate for enzymes that cleave it, including sirtuins, PARPs, and CD38. These enzymes consume NAD+ and release nicotinamide and ADP-ribose or related products. The dual roles as redox cofactor and signaling substrate connect NAD+ to DNA repair, circadian regulation, and calcium signaling. Cellular NAD+ concentrations vary by tissue, time of day, and stress exposure. How these consumption pathways interact with redox balance remains an active area of research.
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.
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.
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.
Nicotinamide adenine dinucleotide, abbreviated NAD+, is a dinucleotide built from adenine, nicotinamide, two ribose sugars, and two phosphate groups. The oxidized form carries a positive charge on the nicotinamide ring, while the reduced form, NADH, is neutral. This pair acts as a reversible electron carrier in cells. NAD+ is present in bacteria, plants, animals, and fungi. Its structure allows it to accept and donate electrons without being consumed in the reactions it supports.
=== Quality and safety === To assure supplements have sufficient quality, standardization, and safety for public consumption, research efforts have focused on development of reference materials for supplement manufacturing and monitoring. High-dose products have received research attention, especially for emergency situations such as vitamin A deficiency in malnutrition of children, and for women taking folate supplements to reduce the risk of breast cancer.
H2NCH2CH2NH2 + 4 CH2O + 4 NaCN + 4 H2O → (NaO2CCH2)2NCH2CH2N(CH2CO2Na)2 + 4 NH3 (NaO2CCH2)2NCH2CH2N(CH2CO2Na)2 + 4 HCl → (HO2CCH2)2NCH2CH2N(CH2CO2H)2 + 4 NaCl This process is used to produce about 80,000 tonnes of EDTA each year. Impurities cogenerated by this route include glycine and nitrilotriacetic acid; they arise from reactions of the ammonia coproduct.
=== Recommended levels === Various government institutions have proposed different recommendations for the amount of daily intake of vitamin D. These vary according to age, pregnancy, or lactation, and the extent assumptions are made regarding skin synthesis. Older recommendations were lower. For example, the US Adequate Intake recommendations from 1997 were 200 IU/day for infants, children, adults to age 50, and women during pregnancy or lactation, 400 IU/day for ages 51–70, and 600 IU/day for 71 and older. Conversion: 1 μg (microgram) = 40 IU (international unit). For dietary recommendation and food labeling purposes government agencies consider vitamin D3 and D2 bioequivalent.
Atrophic gastritis is a process of chronic inflammation of the gastric mucosa of the stomach, leading to a loss of gastric glandular cells and their eventual replacement by intestinal and fibrous tissues. As a result, the stomach's secretion of essential substances such as hydrochloric acid, pepsin, and intrinsic factor is impaired, leading to digestive problems. The most common are pernicious anemia possibly leading to vitamin B12 deficiency; and malabsorption of iron, leading to iron deficiency anaemia. It can be caused by persistent infection with Helicobacter pylori, or can be autoimmune in origin. Those with autoimmune atrophic gastritis (Type A gastritis) are statistically more likely to develop gastric carcinoma (a form of stomach cancer), Hashimoto's thyroiditis, and achlorhydria. Type A gastritis primarily affects the fundus (body) of the stomach and is more common with pernicious anemia. Type B gastritis primarily affects the antrum, and is more common with H. pylori infection.
The dinoflagellates are yet another very large and diverse group, around half of which are at least partially photosynthetic (i.e. mixotrophic). Dinoflagellate chloroplasts have relatively complex history. Most dinoflagellate chloroplasts are secondary red algal derived chloroplasts. Many dinoflagellates have lost the chloroplast (becoming nonphotosynthetic), some of these have replaced it though tertiary endosymbiosis. Others replaced their original chloroplast with a green algal derived chloroplast. The peridinin chloroplast is thought to be the dinophytes' "original" chloroplast, which has been lost, reduced, replaced, or has company in several other dinophyte lineages. The most common dinophyte chloroplast is the peridinin-type chloroplast, characterized by the carotenoid pigment peridinin in their chloroplasts, along with chlorophyll a and chlorophyll c2. Peridinin is not found in any other group of chloroplasts. The peridinin chloroplast is bounded by three membranes (occasionally two), having lost the red algal endosymbiont's original cell membrane. The outermost membrane is not connected to the endoplasmic reticulum. They contain a pyrenoid, and have triplet-stacked thylakoids. Starch is found outside the chloroplast. Peridinin chloroplasts also have DNA that is highly reduced and fragmented into many small circles. Most of the genome has migrated to the nucleus, and only critical photosynthesis-related genes remain in the chloroplast.
Sources: en.wikipedia.org
The Romanian revolution (Romanian: Revoluția română) was a period of violent civil unrest in the Socialist Republic of Romania during December 1989 as a part of the revolutions of 1989 that occurred in several countries around the world, primarily within the Eastern Bloc. The Romanian revolution started in the city of Timișoara and soon spread throughout the country, ultimately culminating in the drumhead trial and execution of longtime Romanian Communist Party (PCR) General Secretary Nicolae Ceaușescu and his wife Elena, and the end of 42 years of Communist rule in Romania. It was also the last removal of a Marxist–Leninist government in a Warsaw Pact country during the events of 1989, and the only one that violently overthrew a country's leadership and executed its leader; according to estimates, over one thousand people died and thousands more were injured. Following World War II, Romania found itself inside the Soviet sphere of influence, with Communist rule officially declared in 1947. In April 1964, when Romania published a general policy paper worked out under Gheorghe Gheorghiu-Dej's instructions, the country was well on its way of carefully breaking away from Soviet control. Nicolae Ceaușescu became the country's leader the following year. Under his rule, Romania experienced a brief waning of internal repression that led to a positive image both at home and in the West. However, repression again intensified by the 1970s, and Ceaușescu's regime eventually became one of the most repressive in the world and one of the most repressive of modern times.
=== Corporate management === Chipotle's team includes a residing corporate office of managers and its board of directors. Members of both teams are appointed to serve on committees: audit, compensation, and nominating and corporate governance. By late 2016, the top management team consisted of the chief executive officer, Steve Ells; the chief financial officer, Jack R. Hartung; the chief marketing and development officer, Mark Crumpacker. At that time, the board of directors consists of: Ells, Patrick Flynn, Albert Baldocchi, Neil Flanzraich, Darlene Friedman, Stephen Gillet, Kimbal Musk and John Charlesworth. On March 14, 2018, it was reported that Mark Crumpacker, who had previously been charged in a 2016 cocaine ring indictment, would be leaving the company. Ells was chairman of the company, and was chief executive officer until November 2017. He had a 1.25% stake in the company in 2010. The labor-market research firm Glassdoor reported that Ells earned $29 million in 2014, versus a median of $19,000 for Chipotle's workers, making the CEO-to-worker pay ratio 1522:1. On February 13, 2018, Chipotle announced that Taco Bell CEO Brian Niccol would replace Ells as CEO starting on March 5 while Ells would retain his chairman position. On March 6, 2020, Ells resigned as chairman and left the board of directors, breaking his final ties to the company. At the same time, Niccol was appointed chairman, and the size of the board was reduced from ten to seven directors. On August 13, 2024, Starbucks announced it was hiring Niccol as its next CEO.
Intracerebroventricular injection (often abbreviated as ICV injection) is a route of administration for drugs via injection into the cerebral ventricles so that it reaches the cerebrospinal fluid (CSF). This route of administration is often used to bypass the blood-brain barrier because it can prevent important medications from reaching the central nervous system. This injection method is widely used in diseased mice models to study the effect of drugs, plasmid DNA, and viral vectors on the central nervous system. In humans, ICV injection can be used for the administration of drugs for various reasons. Examples include the treatment of Spinal Muscular Atrophy (SMA), the administration of chemotherapy in gliomas, and the administration of drugs for long-term pain management. ICV injection is also used in the creation of diseased animal models specifically to model neurological disorders.
== History == The use of drugs in sports goes back centuries, about back to the very invention of the concept of sports. In ancient times, when the fittest of a nation were selected as athletes or combatants, they were fed diets and given treatments considered beneficial to help increase muscle. For instance, Scandinavian mythology says Berserkers could drink a mixture called "butotens" to greatly improve their physical power at the risk of insanity, which is thought to have been prepared using the Amanita muscaria mushroom. The ancient Olympics in Greece have been alleged to have had forms of doping. In ancient Rome, where chariot racing had become a huge part of their culture, athletes drank herbal infusions to strengthen them before chariot races. From that moment, people started to introduce their specific diets to improve their performance. Lots of athletes were mainly focusing on achieving superiority and winning the competition by increasing muscle strength capacity and endurance. Charmis, the Spartan winner of the Stade race in the Olympic Games of 668 BC, introduced the special diet of consuming enough dried figs during the training period. A participant in an endurance walking race in Britain, Abraham Wood, said in 1807 that he had used laudanum (which contains opiates) to keep him awake for 24 hours while competing against Robert Barclay Allardyce. By April 1877, walking races had stretched to 800 kilometres (500 mi) and the following year, also at the Agricultural Hall in Islington, London, to 840 kilometres (520 mi). The Illustrated London News chided:
=== 1945–1979: Post-war Japan and diversification === After World War II, Ajinomoto was slow to resume production of its seasoning as it lacked sufficient funds to continue production and its factory had been destroyed. In April 1946, the company changed its name to Ajinomoto Co., Ltd. In 1947 production of the seasoning resumed, in addition to the production of new food products such as nucleic acid-based seasonings and processed foods. In May 1949 Ajinomoto was listed on the Japanese stock exchange. By 1950, exports accounted for 95% of the company's revenue, with exports to Southeast Asia, Europe, and the United States increasing in subsequent years. In Europe, AJI-NO-MOTO was used as a seasoning by many processed food manufacturers, including Maggi and C.H. Knorr AG. In 1950, sales in Japan resumed after the lifting of postwar sales controls, surpassing pre-war sales by 1953.
Sources: en.wikipedia.org
Nicotinamide adenine dinucleotide, with the plus sign indicating the oxidized form. It is a coenzyme present in all living cells. The reduced form is NADH.
No. NAD+ is oxidized and accepts electrons, while NADH is reduced and carries them. Together they form a redox pair central to energy metabolism.
NAD+ itself is not a common dietary component in significant amounts. Precursors such as nicotinamide, nicotinic acid, and nicotinamide riboside can be converted through biosynthetic pathways. Direct absorption of intact NAD+ is limited.
Researchers often use enzymatic cycling assays, liquid chromatography, or mass spectrometry. The choice depends on sample size, sensitivity needs, and available equipment. Because NAD+ can degrade quickly, rapid extraction and careful handling are important.