NAD+ UK: What the Studies Show (2026)

By the SARMs Store editorial team, reviewed by the SARMs Store research team. Products on this site are supplied strictly for laboratory research and are not for human consumption. This guide summarises published research; it is not medical advice and contains no instructions for use. 18+ only.

NAD+ at a glance

In short: NAD+ is a coenzyme found in every cell, not a peptide. Most human research has used its precursors, NMN and NR, rather than NAD+ itself.

What NAD+ is

In short: NAD+ (nicotinamide adenine dinucleotide) is a coenzyme that carries electrons in energy metabolism and is used up by the sirtuin and PARP enzymes.

Nicotinamide adenine dinucleotide, written NAD+, is a coenzyme found in every living cell. It shuttles electrons in the reactions that turn food into ATP, and it is the substrate that sirtuins and PARP enzymes consume when they regulate gene expression and repair DNA. It is not a peptide, although it is sold alongside peptides because the same research buyers ask for it. Its concentration in tissues falls with age in animals and, on the limited data available, in humans, which is why it has become a focus of ageing research.

What the research found

In short: Most of the evidence comes from mice given NAD+ precursors. Small human trials show that precursors raise NAD+ in the blood, but effects on function have been modest and inconsistent.

Mouse studies. The most cited work comes from David Sinclair's laboratory at Harvard and from Johan Auwerx's group at EPFL. Raising NAD+ levels in old mice, usually with the precursors nicotinamide mononucleotide (NMN) or nicotinamide riboside (NR), improved mitochondrial function, muscle endurance and insulin sensitivity in several studies published between 2013 and 2018. These are precursor studies; the mice were not given NAD+ directly.

Human trials. Small human trials of NR and NMN since 2016 have shown that oral precursors raise blood NAD+ reliably. Functional outcomes have been modest and inconsistent: some studies report small improvements in muscle insulin sensitivity or walking speed in older adults, others report no change. There is no large, long trial of any NAD+ raising strategy for ageing.

Direct NAD+. Intravenous NAD+ has been used in clinics for decades with almost no controlled data. Oral NAD+ is largely broken down in the gut before absorption, which is why the research literature uses precursors. The lyophilised vial sold for research is the intact coenzyme, and it is a different research question from the precursor supplements in the human trials.

What is missing. No published controlled human trial of injected NAD+ for any ageing or performance endpoint as of October 2026.

NAD+, NADH and the names you will see

In short: NAD+ is the oxidised form of the coenzyme and NADH the reduced form; NMN and NR are precursors that cells turn into NAD+.

NAD+ is the oxidised form of nicotinamide adenine dinucleotide and NADH is the reduced form; cells switch the molecule between the two as they move electrons through energy metabolism. NAD written without the plus sign usually means the same molecule, and beta-NAD is the natural form supplied for research. Searches for "nad+", "nad +" and "nad+ supplement" mix the coenzyme together with its precursors, which is the source of most of the confusion online. The table sets out which is which.

NAD+ supplements and research vials are different things

In short: NAD+ food supplements in Great Britain mostly contain precursors and are regulated as foods, while a lyophilised NAD+ vial is the intact coenzyme supplied for laboratory research only.

In Great Britain, products sold as NAD+ supplements are regulated as foods. Most contain a precursor rather than NAD+ itself, partly because NAD+ taken by mouth is largely broken down in the gut before it reaches the blood, and partly because of food law: a new ingredient needs novel food authorisation before it can be sold, and some precursors have that authorisation while others do not, so the ingredient list matters.

Food supplements cannot claim to treat or prevent disease. A lyophilised NAD+ vial is something else again: the intact coenzyme, supplied for laboratory research, with no food or medicine status at all.

Why NAD+ falls with age

In short: Research points to two causes: more NAD+ being used up by enzymes such as CD38 and PARPs, and less being recycled through the salvage pathway.

Tissue NAD+ falls with age in mice and, on the smaller amount of human data, in people. Two explanations dominate the literature. The first is consumption: enzymes that use NAD+ as fuel, particularly CD38 and the DNA repair enzymes called PARPs, become more active with age and inflammation. Camacho-Pereira and colleagues reported in Cell Metabolism in 2016 that CD38 rises with age in mice and that mice lacking CD38 kept their NAD+ levels.

The second is supply: the salvage pathway that recycles nicotinamide back into NAD+ depends on an enzyme called NAMPT, whose activity also declines in some tissues. A third enzyme, NNMT, removes nicotinamide from that recycling loop altogether, which is why NNMT inhibitors such as 5-Amino-1MQ appear in the same research.

What the human trials measured

In short: The trials mainly show that NR and NMN raise NAD+ in the blood. Few found clear functional changes, and none ran long enough to study ageing.

The human studies are almost all of oral precursors, and their main finding is consistent: NR and NMN raise NAD+ in the blood. Whether that changes anything else is much less clear. Martens and colleagues (Nature Communications, 2018) found NR well tolerated in healthy middle-aged and older adults over six weeks, with a rise in blood NAD+. Elhassan and colleagues (Cell Reports, 2019) found NR raised NAD+ metabolites in the muscle of older men without altering mitochondrial bioenergetics.

Yoshino and colleagues (Science, 2021) reported that NMN increased muscle insulin sensitivity in a small group of postmenopausal women with prediabetes, one of the few positive functional findings. Direct NAD+ has mainly been studied as an intravenous infusion in small pilot work, such as Grant and colleagues (Frontiers in Aging Neuroscience, 2019), who measured how plasma and urine NAD+ metabolites changed during a six-hour infusion. None of these studies ran long enough to say anything about ageing, and the precursor results cannot be transferred to a research vial of NAD+.

Stability, storage and handling

In short: NAD+ is stable as a dry powder but degrades in solution, so unopened vials are kept refrigerated and away from light and moisture.

NAD+ is supplied lyophilised in a sealed vial. It is more stable than most peptides in dry form but degrades in solution, particularly when warm or exposed to light, so keep unopened vials refrigerated at 2 to 8 degrees Celsius and away from moisture. Purity by HPLC is the key certificate figure; identity is confirmed by mass spectrometry.

NAD+ and the other longevity compounds in our range

In short: NAD+, 5-Amino-1MQ, SS-31 and Epithalon all appear in ageing research, but each works differently and their evidence ranges from human trials to mouse studies only.

Each has its own guide: 5-Amino-1MQ, SS-31 and Epithalon.

Legal status in the UK, 2026

In short: NAD+ is not a controlled drug in the UK. As a lyophilised vial it is supplied for laboratory research only, and it is not on the WADA Prohibited List.

NAD+ is not a controlled substance under the Misuse of Drugs Act 1971. In lyophilised vial form it is not a licensed medicine and cannot be sold or advertised for human use; it is supplied strictly for laboratory research. Precursor supplements such as NR are sold as food supplements under separate rules that do not apply to the research vial. NAD+ is not on the WADA Prohibited List.

What to check before buying

In short: Check the milligrams per vial, the HPLC purity, mass spectrometry identity and a batch number that matches the certificate.

Milligrams per vial, HPLC purity, mass spectrometry identity, a batch number matching the certificate, and cold-chain shipping. Every Origin Peptides batch is independently tested and its certificate of analysis is published on the product page and the Lab Testing page.

Frequently asked questions

Is NAD+ a peptide?

No. It is a coenzyme, sold alongside peptides for convenience.

What is the difference between NAD+ and NMN?

NMN is a precursor the cell converts into NAD+. Most human trials used precursors, not NAD+ itself.

Has injected NAD+ been tested in a human trial?

Not in a published controlled trial as of 2026.

Is NAD+ legal in the UK?

Legal to buy and possess as a research compound; not lawful to sell or advertise for human consumption in this format; not banned in sport.

Is NAD the same as NAD+?

Usually, yes. NAD+ is the oxidised form of nicotinamide adenine dinucleotide and NADH is the reduced form. NAD on its own is often used for either.

Is NAD+ absorbed when taken by mouth?

Largely not as the intact molecule. Most of it is broken down in the gut into smaller molecules such as nicotinamide, which is why the human trials mostly used precursors such as NR and NMN.

Is NAD+ banned in sport?

NAD+ itself is not on the WADA Prohibited List. Separately, the list prohibits intravenous infusions or injections of more than 100 mL in any 12 hour period, whatever the substance, except those received in hospital treatment or clinical investigation (section M2.2).

What is the difference between NAD+ and 5-Amino-1MQ?

NAD+ is the coenzyme itself. 5-Amino-1MQ is a small molecule that inhibits NNMT, an enzyme that diverts nicotinamide away from NAD+ recycling. Its evidence is mouse studies only.

Sources

• Yoshino J, Baur JA, Imai SI. NAD+ intermediates: the biology and therapeutic potential of NMN and NR. Cell Metabolism. 2018;27(3):513-528. PubMed 29249689
• Rajman L, Chwalek K, Sinclair DA. Therapeutic potential of NAD-boosting molecules: the in vivo evidence. Cell Metabolism. 2018;27(3):529-547. PubMed 29514064
• 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;9:1286. PubMed 29599478
• 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;23(6):1127-1139. PubMed 27304511
• Elhassan YS, Kluckova K, Fletcher RS, et al. Nicotinamide riboside augments the aged human skeletal muscle NAD+ metabolome and induces transcriptomic and anti-inflammatory signatures. Cell Reports. 2019;28(7):1717-1728. PubMed 31412242
• Yoshino M, Yoshino J, Kayser BD, et al. Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women. Science. 2021;372(6547):1224-1229. PubMed 33888596
• 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;11:257. PubMed 31572171
• World Anti-Doping Agency. Prohibited List 2026, section M2.2.

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