NAD+ Injections: What the Evidence Shows

NAD+ is the most common thing sold beside a GLP-1. In our own register, 142 of 560 sellers list it — more than any other peptide, and nearly always as an injection or a drip. A systematic review published in 2026 screened the entire literature and found no outcomes trials of injected NAD+ at all for the purposes it is sold for.^[1] The evidence people cite is real. It is about a different product.

Oral precursors and injected NAD+ are not the same question

Almost every human trial in this field tests an oral precursor — nicotinamide riboside (NR) or nicotinamide mononucleotide (NMN) — taken as a capsule. What clinics sell is NAD+ itself, pushed into a vein or a muscle. Those are different molecules by a different route, and the trial record does not carry across from one to the other.

The 2026 review is unusually explicit about it. Working to PRISMA methodology across studies published between January 2010 and October 2025, the authors identified 113 eligible studies: 33 human intervention studies, 28 of them randomized, and 80 in rodents. On the injected form their finding is a flat absence — no eligible outcomes trials evaluated intravenous or intramuscular NAD+ itself for anti-aging or wellness indications.^[1]

One non-randomized intravenous NMN study met inclusion, contributing short-term safety and biomarker information. A pharmacokinetic pilot of intravenous NAD+ counted only as context.

— Gallagher and Emmanuel, Ageing Research Reviews, 2026

What the oral evidence actually found

Here the picture is genuinely interesting, and it splits cleanly in two.

• Target engagement: consistent. Oral NR and NMN reliably raise NAD-related metabolites in blood and in cells, and were generally well tolerated over weeks to months.^[1] The supplement does the biochemical thing it claims to do.
• Outcomes: heterogeneous, and often null. Effects on functional, metabolic, vascular and other healthspan-relevant endpoints were inconsistent and frequently absent or specific to a single endpoint.^[1]

That gap between the two bullets is the whole story of this field. Raising a molecule in the blood is not the same as changing how someone feels or functions, and NAD+ has become a case study in the difference. A 2025 review in Nature Metabolism covers the same terrain from the precursor side, setting out the clinical evidence alongside the methodological problems that make it hard to read.^[2]

There are real positives in the record and they deserve naming. A 2021 randomized trial published in Science found that NMN improved muscle insulin sensitivity in prediabetic women.^[3] That is a specific finding, in a specific population, on a specific endpoint — which is exactly how it should be described, and not how it is usually sold.

What this looks like on a seller's site

NAD+ occupies a particular slot in the telehealth catalog. It is rarely the thing you arrived for; it appears once you are already buying something else, usually framed around energy, focus, recovery or aging. Of the 142 sellers in our register that offer it, only ten publish what it costs.

That ratio is worth pausing on. A published price is the easiest disclosure a seller can make, and the overwhelming majority of them do not make it for this product. Our seller comparison shows what each one discloses, and what cannot legally be compounded covers the harder regulatory line that some peptide menus cross.

The honest summary

NAD+ biology is a serious research field, not a fraud. NAD+ does decline with age, augmenting it does measurable things, and rodent work has repeatedly shown improvements across metabolic, mitochondrial, inflammatory and functional measures.^[1] Reviews of NAD across clinical conditions continue to find the safety picture broadly reassuring.^[5]

What has not happened is the step from that to a demonstrated benefit in people, for the injected product, at the price a clinic charges. The 2026 review’s own conclusion is that clinical effectiveness for anti-aging or wellness outcomes remains inconclusive, and that larger randomized trials with longer follow-up are needed — particularly, in its words, for the parenteral approaches.^[1] Those are the ones being sold.