Research
NAD+: what the evidence shows
The human research in this category is real, and most of it is about capsules. A systematic review of the whole field states that no eligible outcomes trial has tested intravenous or intramuscular NAD+ itself for the aging and wellness uses it is sold for. The one placebo-controlled trial of NAD+ given by vein studied hospital patients with heart failure.
- The NAD+ board scores the sellers that publish a NAD+ price, on what each one discloses.
- Set against another compound on the same evidence standard: NAD+ injection vs NAD+ IV and NAD+ vs glutathione.
Three molecules wear one label
Nicotinamide adenine dinucleotide is one substance. Nicotinamide riboside is a second. Nicotinamide mononucleotide is a third. All three are sold under the banner of raising NAD+, and their published records are not interchangeable.
Searching the literature in September 2026 shows how far apart they sit. Nicotinamide riboside returns 941 records and 31 tagged as randomized controlled trials. Nicotinamide mononucleotide returns 1,517 records and 17. Both counts belong to swallowed products.
The phrase forms naming intravenous NAD+ return eleven records between them, and one is tagged as a randomized controlled trial. Reading all eleven is the only way to see what they are, and one of them turns out to be a study of noradrenaline.
Through the identical filter in the same session, aspirin returns 5,085 randomized controlled trials and a nonsense term returns zero. The search is working. What it shows is that a citation list built on the word NAD is mostly reporting on capsules.
What a review of the whole category concluded
A 2026 systematic review of NAD+ supplementation for anti-aging and wellness appeared in a peer-reviewed aging research journal. It followed the PRISMA reporting standard and covered human and rodent intervention studies published between January 2010 and October 2025.
It identified 113 eligible studies. Eighty were in rodents. Thirty-three were human intervention studies, and twenty-eight of those were randomized.
Its finding about the oral precursors is careful and worth quoting. Oral nicotinamide riboside and nicotinamide mononucleotide "consistently demonstrated biochemical target engagement" and were "generally well tolerated over weeks to months." Then the second half: effects on functional, metabolic, vascular and other healthspan-relevant outcomes were "heterogeneous and often null or endpoint-specific."
The sentence that matters most for anyone buying an injection is the next one. "No eligible outcomes trials evaluated intravenous or intramuscular NAD+ itself for anti-aging or wellness indications." One non-randomized intravenous study of a precursor met the criteria and contributed short-term safety and biomarker information. An intravenous NAD+ pharmacokinetic pilot was admitted as contextual evidence only.
Two limits belong with that quotation. The review closed its search in October 2025, and its subject was anti-aging and wellness indications. A trial in a different disease would sit outside it on both counts.
The one placebo-controlled trial of NAD+ given by vein
It exists, and it is not about aging. Published in a cardiovascular drugs journal in January 2026, it enrolled 180 adults with heart failure caused by ischemic cardiomyopathy, at a single center.
Participants received either intravenous NAD+ or a matched placebo for a week, on top of guideline-directed medical therapy. The primary endpoint was the change in a heart-imaging measure of pumping function at one month, and on that measure the treated group improved more than the placebo group.
Every secondary endpoint was reported as a trend rather than a separated result. That covers a blood marker of cardiac strain, a composite of serious cardiac and cerebrovascular events at six months, and the proportion of patients whose functional class improved. The authors called for larger multicenter trials focused on clinical endpoints.
None of that transfers to what these products are marketed for. This was a hospital study, in patients with a diagnosed heart condition, receiving standard cardiac treatment at the same time, over a single week. It reports nothing about energy, cognition, recovery or aging in people who do not have heart failure.
What the infusion study actually found
The pharmacokinetic pilot the review set aside as contextual evidence rewards reading directly. Its result is more interesting than the way it is usually summarized. Published in 2019, it tracked NAD+ and its metabolites in plasma and urine during and after a six-hour intravenous infusion.
The authors described the finding as surprising. No change was seen in plasma NAD+ or in its measured metabolites until after two hours. Their reading was that at that infusion rate the NAD+ was being removed from the plasma rapidly and completely for at least the first two hours.
By six hours, urinary excretion of NAD+ and of one methylated metabolite had risen, while another expected metabolite had not. The authors reported that the profile of metabolites is consistent with two named enzyme activities acting on the molecule.
That is a study of where the material goes. It has no clinical outcome in it, and it was never designed to have one. Treating it as support for a benefit claim is the most common misreading in this category.
What is registered, and what those studies are about
The United States trial registry returns 263 studies naming NAD+ as an intervention, against 2,181 for aspirin and none for a nonsense term in the same session. Reading the intervention field on all 263 is what separates them.
The registered studies that give NAD+ by vein are hospital studies in named clinical conditions. They cover recovery of blood cell production after a cord blood transplant, sudden sensorineural hearing loss, unresectable liver cancer alongside two cancer drugs, immune thrombocytopenia, and one pilot in vascular aging. Several are registered under the name Coenzyme I for Injection.
Two registered trials compare NAD+ given by needle directly against a precursor given the same way. Their listed primary measures are things like blood pressure, heart rate, total NAD measured from a dried blood spot, and a pain questionnaire. Those are measures of delivery and tolerability, not of benefit.
The wellness studies use other routes entirely. In the registry, NAD+ appears as a capsule, as a nasal spray and, in one study of post-viral fatigue, as a skin patch driven by a small electric current. That fatigue study also gave a second drug at the same time, which means no result from it can be attributed to NAD+ alone.
One caution about counting these records at all. A registry search for NAD also returns a cardiac arrest program in which the letters stand for Neighborhood Access Defibrillation, and two more records where they are a typographical error. A count of a string is not a count of a topic.
Where the compound sits on the regulator’s own lists
FDA keeps a list of bulk drug substances nominated for use in compounding under section 503A, sorted into three categories. The version published in May 2026 places nicotinamide adenine dinucleotide in category one, under evaluation, together with the reduced disodium form.
A third entry for the same molecule family sits in category three, nominated without adequate support. It is listed as beta-nicotinamide adenine dinucleotide disodium salt trihydrate. The categories describe the nomination package rather than the chemistry, so one molecule family appearing twice is a statement about paperwork.
A name search of the agency page listing substances that raise significant safety risks returns none of those spellings. Absence from that page is not a safety finding in either direction. It records that the substance has not been placed in the category that page describes.
What category one does and does not permit is set out in the article on how the bulk substances lists work. The short version is that it is a stage in an evaluation, not a decision.
How this compound is graded here, and what would move it
NAD+ carries the middle of the three tiers used here: limited evidence. The tier is earned, and it is earned by the oral precursor literature, where dozens of randomized trials have shown that swallowing a precursor moves the measurement it is supposed to move.
Biochemical target engagement is a real result. It is the reason this compound is not in the bottom tier beside compounds whose entire record is in cells and rodents. It is also, on the review’s own reading, where the consistency stops.
The grade does not distribute evenly across the menu. The best-supported form is the one you swallow, and the form with the least published outcome evidence is the one given in a clinic. A category grade belongs to the compound, and it does not vouch for every route wearing it.
Moving the grade has a clear price. It would take randomized, placebo-controlled trials of the form actually being sold, in people resembling those buying it. Those trials would measure something a person would notice rather than a number a laboratory reports, and run long enough for the effect to hold. The review that found them missing said the same thing in its closing sentence.
Key takeaways
- Nicotinamide riboside and nicotinamide mononucleotide are different substances from NAD+, and they carry almost all of the randomized human data.
- A 2026 systematic review of 113 studies states that no eligible outcomes trial evaluated intravenous or intramuscular NAD+ for anti-aging or wellness uses.
- The one published placebo-controlled trial of intravenous NAD+ studied hospital patients with heart failure over a single week.
- The most cited human infusion study is a pharmacokinetic pilot with no clinical outcome in it.
- Registered studies that give NAD+ by vein are in named diseases; the wellness studies use capsules, sprays and patches.
- FDA lists the molecule family in two different nomination categories, and those categories describe the paperwork rather than the substance.
Frequently asked questions
Are there human trials of NAD+?
Many, and almost all of them study swallowed precursors rather than NAD+ itself. Nicotinamide riboside returns 941 records and 31 tagged as randomized controlled trials as of September 2026, and nicotinamide mononucleotide returns 1,517 and 17. The phrase forms naming intravenous NAD+ return eleven records in total. Aspirin returns 5,085 randomized controlled trials through the identical filter in the same session, and a nonsense term returns zero.
Has NAD+ given by vein been tested against a placebo?
Once, in a published trial, and not for anything this market sells it for. A single-center trial of 180 adults with heart failure from ischemic cardiomyopathy gave intravenous NAD+ or placebo for a week alongside standard cardiac therapy. Its primary measure was a heart-imaging measure of pumping function, which favored the treated group; every secondary endpoint was reported as a trend. A 2026 systematic review of the category states that no eligible outcomes trial has evaluated intravenous or intramuscular NAD+ for anti-aging or wellness indications.
Do the oral precursors actually do anything?
They reliably do one thing. The systematic review found that oral nicotinamide riboside and nicotinamide mononucleotide consistently demonstrated biochemical target engagement and were generally well tolerated over weeks to months. It also found that effects on functional, metabolic, vascular and other healthspan-relevant outcomes were heterogeneous and often null or endpoint-specific. Moving the marker is established. What the marker buys is not.
Why do the trial counts for NAD+ look so large?
Because the phrase pulls in three different substances and several unrelated things. The large randomized counts belong to nicotinamide riboside and nicotinamide mononucleotide, which are capsules. The registry adds noise of its own: a search for NAD returns a cardiac arrest program where the letters stand for Neighborhood Access Defibrillation, plus records where they are a typing error. Splitting the search terms and reading the intervention field is what turns a count into an answer.
What has FDA done with NAD+?
It appears on the agency’s list of bulk drug substances nominated for use in compounding under section 503A. In the May 2026 version, nicotinamide adenine dinucleotide and the reduced disodium form sit in category one, under evaluation. A third entry for beta-nicotinamide adenine dinucleotide disodium salt trihydrate sits in category three, nominated without adequate support. Those categories describe the nomination package, not the chemistry, and category one is a stage in an evaluation rather than a decision.
Does a rising NAD+ level mean the product worked?
It means the material reached the pathway that measurement tracks. Whether that produces a change anyone would notice is a separate question, and it is the question the published record has not settled. The review that pooled the human studies drew exactly that line: target engagement was consistent, and the outcomes people buy these products for were heterogeneous and often null.
Sources
Each document below is named as it names itself, with the date printed on that document rather than the day it was read.
- NAD+ supplementation for anti-aging and wellness: A PRISMA-guided systematic review of preclinical and clinical evidence — Ageing Research Reviews, April 2026
- Effect of Nicotinamide Adenine Dinucleotide on Heart Failure Caused by Ischemic Cardiomyopathy: A Randomized, Placebo-Controlled Trial — American Journal of Cardiovascular Drugs, January 2026
- 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, September 2019
- Bulk Drug Substances Nominated for Use in Compounding Under Section 503A of the Federal Food, Drug, and Cosmetic Act — U.S. Food and Drug Administration, May 2026
- Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks — U.S. Food and Drug Administration, April 2026
- PubMed literature census splitting NAD+ from its oral precursors, run with positive and negative controls through the same filter — National Library of Medicine, September 2026
- Registered study census for nicotinamide adenine dinucleotide, every returned record read, run with a positive control through the same query — ClinicalTrials.gov, National Library of Medicine, September 2026