NAD+ Research, Specifications & Scientific Information

Introduction

NAD+ is the only entry in this library that is not a peptide and not a drug candidate. It is a coenzyme — one of the oldest and most abundant small molecules in biochemistry, present in every cell, and known since the earliest days of enzymology under the name coenzyme I. It appears in this library because it is supplied as a laboratory reagent alongside the peptides, and because the research literature around it has grown in a way that makes careful reading unusually important.

That care is needed for one specific reason. NAD+ has two biochemical jobs, and the second one is what made it interesting to ageing research: besides cycling as a redox carrier, it is consumed outright by sirtuins, poly(ADP-ribose) polymerases and CD38, which cleave it and release nicotinamide ^[8]. Tissue concentrations fall with age across model organisms ^[8], and a large body of work has followed on raising them.

Almost all of that work used precursors — nicotinamide riboside and nicotinamide mononucleotide — not NAD+ itself. The distinction is not pedantic: the molecules differ, the biochemistry of their uptake differs ^[3], and the trials belong to the precursors. This page keeps them separate throughout, and says which is which in every section.

It is a reference record. It describes research. It does not describe use in people or animals, and it carries no guidance of any kind on handling the material.

What Is NAD+?

NAD+ is nicotinamide adenine dinucleotide in its oxidised form: two nucleotides — one carrying nicotinamide, one carrying adenine — joined through a pyrophosphate bridge.

The plus sign is doing real work in that name. It denotes the oxidised species, in which the nicotinamide ring carries a positive charge and can accept a hydride to become NADH. NAD+ and NADH are two states of one couple but are distinct chemical species, and the phosphorylated pair NADP+ and NADPH are different again, serving largely biosynthetic rather than catabolic reactions. Material supplied as one of these is not interchangeable with the others, and identity work has to establish which species is present.

Functionally, the reference review describes two roles. As a coenzyme for redox reactions NAD+ is central to the chemistry of metabolism. As an essential cofactor for non-redox enzymes — sirtuins, CD38, poly(ADP-ribose) polymerases — it participates in a wider set of processes including DNA repair, chromatin remodelling, cellular senescence and immune cell function ^[8].

NAD+ is not approved by the U.S. Food and Drug Administration as a drug for any indication.

NAD+ Specifications

NAD+ is not a peptide and is listed in this library as a peptide-adjacent research compound. It is a dinucleotide: a nicotinamide riboside unit and an adenosine unit joined through a pyrophosphate bridge. The plus sign in the name is not decorative — it denotes the oxidised form, in which the nicotinamide ring carries a positive charge and can accept a hydride. The reduced form, NADH, is a different species with different chemistry, and the phosphorylated pair NADP+ and NADPH are different again and serve largely biosynthetic rather than catabolic reactions. Identity and purity work on supplied material therefore has to establish which species is present, not only which elements. The molecular formula C21H27N7O14P2 and a mass near 663.43 g/mol are carried consistently by PubChem compound identifier 5892 and by the supplier catalog record, and CAS registry number 53-84-9 is the number for the oxidised free acid. Any figure on this page is a reference value: the certificate of analysis supplied with a laboratory order is the record for a given lot.

Values that a public register does not carry are shown as not publicly characterised rather than estimated. Identifiers are reference values; the certificate of analysis supplied with a laboratory order is the record for a given lot.

How Does NAD+ Work?

The two roles are worth separating properly, because conflating them is the origin of most confusion in this area.

As a redox coenzyme, NAD+ is recycled. It accepts a hydride during the oxidation of a substrate, becomes NADH, carries the reducing equivalent, and is regenerated when NADH is oxidised. Nothing is used up. A cell can run this cycle indefinitely on a fixed pool.

As a substrate, NAD+ is consumed. Sirtuins, poly(ADP-ribose) polymerases and CD38 cleave the molecule and release nicotinamide ^[8]. That is not a cycle; it is a drain, and it creates a standing demand that must be met by synthesis. Isotope-tracer work in cell lines found that NAD+ was made from nicotinamide and consumed largely by PARPs and sirtuins, which puts numbers behind that description ^[6].

The second role is why concentration alone is a poor description of the system. A tissue with a low NAD+ concentration and a high turnover rate is in a different state from a tissue with the same concentration and little turnover, and the two cannot be distinguished by measuring the pool. The flux work makes that point directly: reliance on concentration measurements had been a limitation in understanding NAD+ metabolism ^[6].

NAD+ Mechanism of Action

In vitro research

The isotope-tracer study is the clearest quantitative account of how the system behaves. In cell lines, NAD+ was synthesised from nicotinamide and consumed largely by PARPs and sirtuins. In whole animals, synthesis from tryptophan occurred selectively in the liver, which then exported nicotinamide to the rest of the body. Fluxes varied widely between tissues — high in the small intestine and spleen, low in skeletal tissue ^[6].

The uptake question is the one that matters most for anyone reasoning about extracellular dinucleotides. Using stable-isotope-labelled compounds, one study showed that nicotinamide mononucleotide is metabolised extracellularly to nicotinamide riboside, which the cell then imports and converts to NAD+, and that the kinase NRK1 is necessary and rate-limiting for the use of either precursor ^[3]. In other words, the phosphorylated precursor does not simply cross the membrane; it is processed first.

The route of administration changes the answer as well. Intravenous administration of nicotinamide riboside or mononucleotide delivered the intact molecules to multiple tissues, whereas the same agents given orally were metabolised to nicotinamide in the liver before reaching them ^[6]. Two administration routes of the same compound therefore present two different molecules to the periphery.

For analytical work, the relevant point is that NAD+ is a hydrolytically labile dinucleotide. Identity and purity of supplied material are established chromatographically with detection against a reference standard, and the oxidation state has to be confirmed rather than assumed.

What Is NAD+ Being Researched For?

The literature divides into parts that are often quoted as though they were one body of evidence.

• Fundamental enzymology and flux — how NAD+ is made, where, and what consumes it ^{[6, 3]}.
• Ageing biology — the decline in tissue concentrations with age, and the mechanisms behind it ^{[8, 1]}.
• Precursor administration in animals — long-term studies using nicotinamide mononucleotide or riboside ^[4].
• Precursor administration in humans — the randomised controlled trials, all of which studied a precursor ^{[2, 5, 9]}.
• Administered NAD+ in humans — one small published pharmacokinetic study ^[7].

The size difference between the last two categories is the single most important fact on this page. When a claim is made about "NAD+ therapy", the evidence behind it is almost always precursor evidence.

Human Research on NAD+

Human clinical research

Results from pharmaceutical clinical trials describe the investigational material and populations used in those studies and should not be interpreted as establishing the effects of research-grade materials offered for laboratory use.

This section covers the human work on NAD+ itself. Human research on its precursors is a separate literature and is described further down, under its own heading, so that the two are not read together by accident.

Pilot study of intravenous NAD+

Population and design. A pilot study documenting changes in plasma and urine concentrations of NAD+ and its metabolites during and after a six-hour intravenous infusion at 3 µmol per minute. The authors note explicitly that, while the efficacy of precursors such as nicotinamide riboside in raising plasma NAD+ had been documented, no data existed on the fate of directly infused NAD+ in a human cohort ^[7].

Endpoint. Plasma and urinary NAD+ and its metabolites — nicotinamide, methylnicotinamide, adenosine diphosphate ribose and nicotinamide mononucleotide — sampled during and after infusion ^[7].

Result. No change in plasma NAD+ or in its metabolites was observed until after two hours. Increased urinary excretion of methylnicotinamide and of NAD+ was detected at six hours, with no significant rise in urinary nicotinamide. The authors report three findings: that at that infusion rate NAD+ is rapidly and completely removed from plasma for at least the first two hours; that the metabolite profile is consistent with NAD+ glycohydrolase and NAD+ pyrophosphatase activity; and that the urinary excretion products include NAD+ itself and methylnicotinamide but not nicotinamide ^[7].

Limitations. A pilot study, reporting the disposition of an infused molecule and nothing else. It measures where NAD+ goes; it does not test whether administering it changes anything. The finding that plasma concentrations did not move for two hours is itself a caution against assuming that infused NAD+ behaves like an expanded pool.

Preclinical Research on NAD+

Animal research

The animal literature explains why the decline in NAD+ with age became a research target, and it is mechanistic rather than therapeutic.

CD38 and the age-related decline

Expression and activity of the NADase CD38 increase with age in mice, and CD38 was shown to be required for the age-related decline in NAD+ and for the accompanying mitochondrial dysfunction, through a pathway mediated at least in part by regulation of SIRT3 activity. The same work identified CD38 as the principal enzyme degrading nicotinamide mononucleotide in vivo ^[1].

That second finding is the more practically consequential of the two: an enzyme that both drives the decline and destroys the precursor used to counter it places a real constraint on the strategy.

Tissue-specific synthesis in whole animals

The flux work extended into mice showed that NAD+ is synthesised from tryptophan selectively in the liver, which then exports nicotinamide to other tissues, and that turnover differs substantially between organs ^[6]. Whole-body NAD+ metabolism is therefore not uniform, and a systemic intervention does not reach every tissue in the same way.

Long-term precursor administration in ageing mice

A twelve-month study administered nicotinamide mononucleotide orally to normally ageing wild-type mice. The precursor was reported to be quickly used to synthesise NAD+ in tissues, and, without obvious toxicity or deleterious effects, to mitigate age-associated physiological decline across several measures including insulin sensitivity, plasma lipid profile, physical activity and eye function; it also prevented age-associated gene expression changes in key metabolic organs ^[4].

That is a precursor study, not an NAD+ study, and is described here because it is the animal work most often invoked when NAD+ is discussed.

Findings described in this section were observed in animals. Mouse models of ageing are standard preclinical tools, and nothing in them establishes anything about humans.

Other Areas of NAD+ Research

Human clinical research

Results from pharmaceutical clinical trials describe the investigational material and populations used in those studies and should not be interpreted as establishing the effects of research-grade materials offered for laboratory use.

This section is about precursors, not about NAD+. Nicotinamide riboside and nicotinamide mononucleotide are different molecules from NAD+, with different uptake biochemistry ^[3]. What follows applies to them, and is set out here so that the distinction is visible rather than buried.

First clinical pharmacokinetics of nicotinamide riboside. Single oral administrations of 100, 300 and 1,000 mg produced increases in the blood NAD+ metabolome proportional to the amount given, in what the authors describe as the first clinical trial of nicotinamide riboside pharmacokinetics in humans. A pilot observation in one individual showed blood NAD+ rising as much as 2.7-fold after a single oral administration. The study also reported that nicotinic acid adenine dinucleotide, previously not thought to lie on the route from riboside to NAD+, is formed from it, and proposed the rise in that metabolite as a sensitive biomarker of NAD+ repletion ^[2]. The authors' declared interests include employment by and equity in the supplier that sponsored the study, which is stated in the paper.

Randomised crossover trial of chronic supplementation. A 2 × 6-week randomised, double-blind, placebo-controlled crossover trial in healthy middle-aged and older adults reported that chronic nicotinamide riboside supplementation was well tolerated and effectively stimulated NAD+ metabolism. On physiological function the authors are explicitly preliminary: they describe their results as an initial insight and suggest that future trials should further assess potential benefits for blood pressure and arterial stiffness — that is, a hypothesis for later study rather than a demonstrated effect ^[5].

Randomised controlled trial of nicotinamide mononucleotide in prediabetes. A 10-week randomised, placebo-controlled, double-blind trial in postmenopausal women with prediabetes who were overweight or obese. Insulin-stimulated glucose disposal, assessed by hyperinsulinaemic-euglycaemic clamp, and skeletal muscle insulin signalling — phosphorylation of AKT and mTOR — increased after the precursor and did not change after placebo. Expression of platelet-derived growth factor receptor β and other remodelling-related genes was up-regulated ^{[9, 10]}. The registered trial enrolled 25 participants. This result attracted a published technical comment and a response from the authors, which is part of its record.

The pattern across all three is consistent and worth stating plainly: precursor administration reliably raises measured NAD+ metabolites in humans, and the evidence for downstream physiological effects is early, small and in places contested. None of it is evidence about administering NAD+ itself.

Current Research Status

Status as of September 22, 2026. This block is rendered from maintained fields, not from prose, so it cannot go stale in one place and stay current in another.

NAD+ vs Related Compounds

The comparisons that matter for NAD+ are with its own precursors and with the compounds studied in the same literature by other means.

Against its precursors

Nicotinamide riboside and nicotinamide mononucleotide are smaller molecules converted into NAD+ by the cell. They are not NAD+, and the difference is mechanical: extracellular mononucleotide is converted to riboside before uptake, and the kinase NRK1 is necessary and rate-limiting for using either ^[3]. Essentially all of the randomised human evidence in this field belongs to the precursors.

Against its own redox partner

NADH is the reduced form of the same couple, and NADP+/NADPH the phosphorylated pair. Distinct species, distinct chemistry, not interchangeable as reagents.

Against peptides in the same literature

MOTS-c and SS-31 appear in overlapping mitochondrial and metabolic research, but they are peptides acting by entirely different means. Shared subject area, unrelated mechanisms.

Regulatory position

NAD+ is not approved as a drug in the United States for any indication. Certain precursors are marketed as dietary ingredients, which is a different regulatory category and confers nothing on NAD+.

No comparison of effect between these compounds is made on this page. Where comparative data exist they belong to the papers that report them.

Chemical & Molecular Characteristics

NAD+ is a dinucleotide, not a peptide, and it has no amino acid sequence. Its specification table therefore leaves the sequence and receptor fields empty, which is a property of the molecule rather than a gap in the record.

Three points are worth stating about the material.

The charge in the name is the species. NAD+ is the oxidised form. A reagent labelled NAD, NADH, NADP+ or NADPH is not the same substance, and an assay built on one of them will not behave correctly on another. This is the first thing to confirm on a certificate of analysis for this material.

It is labile. The pyrophosphate bridge and the glycosidic bond at the nicotinamide ring are both hydrolysable, and the metabolite profile reported in the human infusion study — consistent with glycohydrolase and pyrophosphatase activity — is a description of exactly those bonds being broken in vivo ^[7]. In a laboratory setting the same chemistry is the reason storage conditions and solution stability matter more for this reagent than for a lyophilised peptide.

The identifiers agree across registers. CAS registry number 53-84-9 validates against the CAS check-digit algorithm and is the number for the oxidised free acid; UNII 0U46U6E8UK resolves for the same substance; and PubChem compound identifier 5892, listed under the name nadide, carries the molecular formula C21H27N7O14P2 with a mass of approximately 663.4 g/mol. Those values match the supplier catalog record for the material offered as a laboratory reagent.

Analytical Specifications

Analytical figures are lot-specific. Fields the catalog does not carry for the current lot are omitted rather than filled with a typical value. The certificate of analysis and the safety data sheet for the exact lot supplied are provided with a laboratory order; no purity figure on this page is a substitute for that document.

Frequently Asked Questions

Scientific References

1. Camacho-Pereira J, Tarragó MG, Chini CCS, et al.. CD38 Dictates Age-Related NAD Decline and Mitochondrial Dysfunction through an SIRT3-Dependent Mechanism Cell metabolism; 2016. PMID 27304511 doi:10.1016/j.cmet.2016.05.006
2. Trammell SA, Schmidt MS, Weidemann BJ, et al.. Nicotinamide riboside is uniquely and orally bioavailable in mice and humans Nature communications; 2016. PMID 27721479 doi:10.1038/ncomms12948
3. Ratajczak J, Joffraud M, Trammell SA, et al.. NRK1 controls nicotinamide mononucleotide and nicotinamide riboside metabolism in mammalian cells Nature communications; 2016. PMID 27725675 doi:10.1038/ncomms13103
4. Mills KF, Yoshida S, Stein LR, et al.. Long-Term Administration of Nicotinamide Mononucleotide Mitigates Age-Associated Physiological Decline in Mice Cell metabolism; 2016. PMID 28068222 doi:10.1016/j.cmet.2016.09.013
5. Martens CR, Denman BA, Mazzo MR, et al.. Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD(+) in healthy middle-aged and older adults Nature communications; 2018. PMID 29599478 doi:10.1038/s41467-018-03421-7
6. Liu L, Su X, Quinn WJ 3rd, et al.. Quantitative Analysis of NAD Synthesis-Breakdown Fluxes Cell metabolism; 2018. PMID 29685734 doi:10.1016/j.cmet.2018.03.018
7. Grant R, Berg J, Mestayer R, et al.. A Pilot Study Investigating Changes in the Human Plasma and Urine NAD+ Metabolome During a 6 Hour Intravenous Infusion of NAD Frontiers in aging neuroscience; 2019. PMID 31572171 doi:10.3389/fnagi.2019.00257
8. Covarrubias AJ, Perrone R, Grozio A, et al.. NAD(+) metabolism and its roles in cellular processes during ageing Nature reviews. Molecular cell biology; 2021. PMID 33353981 doi:10.1038/s41580-020-00313-x
9. Yoshino M, Yoshino J, Kayser BD, et al.. Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women Science (New York, N.Y.); 2021. PMID 33888596 doi:10.1126/science.abe9985
10. Effect of "Nicotinamide Mononucleotide" (NMN) on Cardiometabolic Function 2017. NCT03151239

Every identifier above is resolved against PubMed, Crossref or ClinicalTrials.gov at build time, and the title returned by the register is compared with the title stored here. A page does not publish if a reference fails to resolve.

Research-Use Information

For in vitro research use only. This material is a laboratory reagent. It is not a drug, food, dietary supplement, or cosmetic and is not for human or veterinary use, including ingestion, injection, or any other administration. No information on this page describes or implies any effect in humans or animals. Sold only to researchers under our Terms of Sale.

Related laboratory reagent: NAD+ specifications and lot documentation