NAD+: sourcing, documentation and price

Nicotinamide adenine dinucleotide, abbreviated NAD+, is the formal name of the pyridine dinucleotide cofactor sold as a research chemical; it also appears in the literature as diphosphopyridine nucleotide (DPN) and as NAD. It is a dinucleotide built from an adenine nucleotide linked to a nicotinamide nucleotide through a pyrophosphate bridge, and it is the oxidized member of the NAD+/NADH redox pair. The evidence block supplied for this page does not give a CAS number, molecular formula, molecular weight or sequence for NAD+, so none is stated here; purchasers should obtain those identifiers from the supplier's certificate of analysis rather than from this page. The work described below centres on NAD+ as the substrate and product of the NAD+-consuming and NAD+-generating enzyme families, and on the salvage pathway by which the precursors nicotinamide, nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN) are converted into it.

NAD+ is not a receptor ligand; it is a coenzyme. The pathway that dominates the registered trial record is the NAD+ salvage pathway, in which nicotinamide phosphoribosyltransferase and nicotinamide mononucleotide adenylyltransferase regenerate NAD+ from nicotinamide and from the ribosides. The studies below are registered clinical trials and one observational protocol; they document what was measured, in which population, and over what interval. Where a finding comes from a non-clinical model, that is stated.

Research Studies

NAD+ and whole-blood NAD+ change in healthy adults

A registered clinical trial set out to assess the absorption, safety and efficacy of an oral NAD+ supplement in healthy adults [1]. The primary question was the change in NAD+ levels in whole blood from baseline to day 56, comparing the NAD+ supplement against placebo. Participants were asked to complete questionnaires, provide blood samples, consume either the supplement or placebo for 55 days, and undergo evaluation of endothelial function [1]. This is the only study in the evidence block that administers NAD+ itself rather than a precursor, and it is the reference point for anyone documenting an oral NAD+ product against a clinical protocol.

Nicotinamide and retinal nerve cell layer thickness in primary open-angle glaucoma

The NADIR trial is testing whether high-dose nicotinamide, a vitamin B3 form, protects retinal nerve cells in adults with primary open-angle glaucoma who are already receiving standard eye drops or laser treatment [2]. The primary question is whether adding nicotinamide to standard therapy slows the rate of thinning of the inner retinal nerve cell layer, measured by a non-invasive eye scan, compared with standard therapy alone over 12 months [2]. Participants are randomised to two groups; the treatment group takes nicotinamide tablets by mouth starting at 1.5 grams per day [2]. The population is adults with POAG on existing therapy, and the outcome is structural, not symptomatic.

Nicotinamide riboside and six-minute walk distance in peripheral artery disease

The NICE-PAD II trial tests the hypothesis that, among people with peripheral artery disease aged 50 and older, participants randomised to nicotinamide riboside will show greater improvement or less decline in six-minute walk distance at six-month follow-up than those randomised to placebo [3]. The study randomises 250 participants with PAD aged 50 and older to NR or placebo for six months [3]. The primary outcome is change in six-minute walk distance at six months; secondary outcomes include the Walking Impairment Questionnaire distance score, the PROMIS Mobility score, and calf muscle perfusion measured by magnetic resonance arterial spin labelling [3].

Nicotinamide and post-COVID syndrome in patients with documented tryptophan deficiency

An observational study is examining CICR-NAM, a nicotinamide formulation developed as a food for special medicinal purposes, in patients with post-COVID syndrome [4]. The rationale given is that changes in tryptophan metabolism, energy metabolism and the gut microbiome may occur in this population, and that in an earlier nutritional study patients with COVID-19 recovered physical performance more quickly when taking nicotinamide, with responders developing post-COVID syndrome less frequently [4]. The CICR-NAM tablets were developed at the University Hospital Schleswig-Holstein in Kiel to release the active substance selectively in the lower intestine and have been reported as very well tolerated in several studies [4]. Patients with post-COVID syndrome and documented tryptophan deficiency may take the preparation under the protocol [4].

MIB-626 (β-nicotinamide mononucleotide) and safety in adults with Down syndrome

A trial is determining the safety and tolerability of increasing doses of MIB-626, a microcrystalline form of β-nicotinamide mononucleotide, given daily for 28 consecutive days to adults with Down syndrome [6]. The study also explores pharmacokinetics, how the drug moves through the body over time, and pharmacodynamics, how it affects the body in different ways [6]. Participants are monitored for adverse events, with laboratory tests of blood counts, chemistries and coagulation profile, and electrocardiogram [6]. The trial enrols 24 adults with Down syndrome [6]. This is a dose-escalation safety study in a defined clinical population, not a general-population efficacy study.

Topical niacinamide riboside and facial skin ageing

A trial is evaluating topical niacinamide riboside, also called nicotinamide riboside, on the signs of facial skin ageing [7]. The protocol describes NR as an endogenous compound and a precursor to NAD+, and cites published work reporting that skin NAD+ levels were negatively correlated with age in both males and females, and that aged skin was also correlated with an increase in DNA damage [7]. On that basis the protocol proposes that supporting skin NAD+ with precursors such as NR may be a strategy against the DNA damage associated with undesirable signs of skin ageing, supporting skin cell resilience [7]. The use of NR as a dietary supplement is described in the protocol as having produced effective, efficient and reproducible results [7]. The model here is topical application to facial skin, not systemic administration.

Nicotinamide riboside and cerebral blood vessel health, memory and physical function in Parkinson's disease

A trial is testing whether nicotinamide riboside can improve blood vessel health in the brain, memory and physical function in eligible participants with Parkinson's disease [8]. NR is described as investigational for this study because it is not yet established for this specific use [8]. The main questions are whether NR improves non-invasive measures of blood vessel health in the brain, and whether it improves memory testing results and physical function [8]. Participants receiving NR are compared with those receiving placebo to see whether NR has beneficial effects [8].

Comparison of the registered protocols

The table below sets out the compound, population, route and primary outcome for each registered study in the evidence block, so that sourcing and documentation decisions can be matched to the protocol they will be cited against.

Adjacent evidence and what it does not cover

One further registered study in the evidence block concerns rapid UTI diagnostics in lower urinary tract dysfunction among catheter users, enrolling patients who present believing they have a UTI and assigning them by a standard-of-care symptom measure to a presumed UTI or presumed no UTI arm [5]. It does not involve NAD+ or any of its precursors and is listed here only to mark the boundary of the evidence block: it is not part of the NAD+ literature and should not be cited as such.

Separately, a network pharmacology, molecular docking and multi-omics study reports that Guizhi Wuling Decoction alleviates myocardial fibrosis by restoring mitochondrial homeostasis [9]. That finding is a fact about a herbal decoction in a preclinical model and is not evidence about NAD+; it is noted because mitochondrial homeostasis is a recurring theme in NAD+ research, but no claim about NAD+ should be built on it.

What the evidence does not establish

None of the registered protocols in the evidence block reports a completed result. The NAD+ trial measures whole-blood NAD+ change and endothelial function [1]; the nicotinamide glaucoma trial measures retinal layer thickness [2]; the NR peripheral artery disease trial measures walk distance [3]; the post-COVID study is observational [4]; the NMN study is a 28-day safety and pharmacokinetic study in adults with Down syndrome [6]; the topical NR study concerns facial skin [7]; and the Parkinson's disease trial is described as investigational for that use [8]. No claim of clinical benefit in a general population can be sourced from this block, and no human dose should be inferred from the doses quoted in the protocols, which are trial-specific and administered under supervision.

If you are reading this for personal health reasons

This material is sold for laboratory research use only, and nothing on this page is medical or dosing guidance. We do not provide dosing information, and we do not advise anyone to take this compound. If you are considering a compound for yourself, speak to a licensed clinician.

Sources

• [1] A Clinical Trial to Assess the Absorption, Safety, and Efficacy of an Oral Nicotinamide Adenine Dinucleotide (NAD+) Supplement in Healthy Adults — https://clinicaltrials.gov/study/NCT07692633
• [2] Nicotinamide for Retinal Protection in Primary Open-Angle Glaucoma (NADIR Trial) — https://clinicaltrials.gov/study/NCT07808333
• [3] The NICE-PAD II Trial — https://clinicaltrials.gov/study/NCT07782671
• [4] Observational Study With CICR-NAM as a Food for Special Medicinal Purposes in Post-COVID Syndrome (PCS) — https://clinicaltrials.gov/study/NCT07798570
• [5] Rapid UTI Diagnostics in Lower Urinary Tract Dysfunction Among Catheter Users — https://clinicaltrials.gov/study/NCT07784829
• [6] NAD Augmentation to Prevent or Reverse Alzheimer's Disease in People With Down Syndrome — https://clinicaltrials.gov/study/NCT07278492
• [7] Efficacy of Topical Niacinamide Riboside on the Signs of Facial Skin Aging — https://clinicaltrials.gov/study/NCT07774000
• [8] NAD Supplementation in Parkinson's Disease — https://clinicaltrials.gov/study/NCT07703137
• [9] Guizhi Wuling Decoction alleviates myocardial fibrosis by restoring mitochondrial homeostasis: Evidence from network pharmacology, molecular docking, and multi-omics integration. — https://pubmed.ncbi.nlm.nih.gov/42462419/