What it is

NAD+ is a coenzyme, not a peptide. It is a dinucleotide, chemically a different class of molecule from everything else profiled here, and it is grouped with peptides by the market rather than by chemistry.

That distinction is not pedantry. It changes which failure modes matter and which documents are worth reading.

What does the research on NAD+ actually show?

NAD+ is a coenzyme, not a peptide, and almost every controlled human trial in this area studied a precursor taken by mouth, not NAD+ itself. Nicotinamide riboside and nicotinamide mononucleotide reliably raise blood NAD levels in humans. Whether raising that level changes how anyone feels or functions is where the results get thin.

NAD+ stands for nicotinamide adenine dinucleotide. It appears on this site because it is sold through the same channels and carries the same documentation questions as the peptides, not because it belongs to the same chemical class.

Study	Design	What it found
NMN dose-ranging, Geroscience 2022	Randomised, 300 / 600 / 900 mg daily	Blood NAD rose with dose; six-minute walk distance improved
NMN in older adults, Geroscience 2024	Randomised, 250 mg daily, 12 weeks	Blood NAD rose; walking speed maintained, sleep quality improved
Nicotinamide riboside in long COVID (NCT04809974)	Randomised, 2,000 mg daily, up to 20 weeks	Primary cognitive and memory endpoints not met
IV NAD+ vs IV NR, Frontiers in Aging 2026	Retrospective chart review, 6 vs 8 people	All six IV NAD+ recipients had moderate to severe symptoms during infusion

What the intravenous NAD+ data look like

The best available human record for intravenous NAD+ is not a trial. It is a retrospective review of records from a commercial wellness clinic, covering six people who received 500 mg IV NAD+ and eight who received the same dose of nicotinamide riboside, over four consecutive days. Every one of the six NAD+ recipients reported moderate to severe abdominal cramping, diarrhoea, nausea, vomiting, raised heart rate, throat pain and chest pressure during infusion. Symptoms stopped when the infusion did. Average infusion time was 97 minutes for NAD+ against 37 minutes for nicotinamide riboside.

The authors were explicit about the limits: retrospective design, fourteen people in total, no placebo control, commercial funding, and no reliable measurement of NAD+ concentration. It is the honest state of the evidence rather than a verdict.

What this evidence does not cover

Primary sources

• The efficacy and safety of β-nicotinamide mononucleotide (NMN) supplementation. Geroscience, 2022 (PMID 36482258)
• Ingestion of β-nicotinamide mononucleotide increased blood NAD levels. Geroscience, 2024 (PMID 38789831)
• Intravenous infusion of NAD+ versus nicotinamide riboside: a retrospective tolerability pilot study. Front Aging, 2026
• ClinicalTrials.gov NCT04809974: nicotinamide riboside for persistent cognitive and physical symptoms (completed)
• PubChem CID 5892: NAD+
• Nicotinamide adenine dinucleotide on Wikipedia

What it costs

Vial sizes differ enough that headline prices mislead, so normalise everything to price per milligram before comparing. A 20 mg vial at $40 works out to $2.00 per milligram; a 10 mg vial at $25 looks cheaper on the shelf but costs $2.50 per milligram.

That is a 25 percent difference hidden entirely by vial size, and it runs in the opposite direction to the sticker price.

What to check

NAD+ is markedly hygroscopic and pH sensitive. In practice that makes storage and handling a larger share of the real risk than the purity documentation is. Material can be exactly what the certificate says and still be compromised by how it was kept.

If you are looking at a blended product, treat a single aggregate purity figure as close to meaningless. A vial reporting 99 percent purity across three components could be almost entirely one of them.

Our NAD+ analysis

Reconstitution calculator

Work out the concentration and the units on the syringe from what is printed on your vial. Arithmetic only — it does not recommend a dose. More on how it works.