Guide

NAD injections and IV therapy: what the research actually shows

NAD injections and IV drips are sold in med spas and wellness clinics across the country. A systematic review published in 2026 went looking for trials of injected NAD and reported that none exist. Almost all the human research is about swallowing something else.

Published September 19, 2026

This page reports what published studies found. It is not medical advice, no provider-patient relationship is created by reading it, and nothing here is a recommendation to use any compound. Talk with a licensed clinician about your own situation. Read the full disclaimer.

First, NAD is not a peptide

Nicotinamide adenine dinucleotide is a coenzyme. It is built from two nucleotides rather than a chain of amino acids, which makes it a different class of molecule from everything else on this site. It appears on peptide clinic menus because the same clinics sell it through the same channels, not because it is related.

Its actual job inside a cell is unglamorous and genuinely important: it carries electrons in the reactions that turn food into usable energy, and it is consumed by several repair enzymes. Cellular levels fall with age, and that observation is the seed of the entire industry built on top of it.

What a 2026 systematic review found when it looked

This is the part worth reading twice. A PRISMA-guided systematic review published in Ageing Research Reviews in 2026 searched peer-reviewed human and rodent intervention studies from January 2010 to October 2025, covering NAD-related compounds given by mouth or parenterally. It identified 113 eligible studies: 33 human intervention studies, of which 28 were randomised, and 80 rodent studies.

Read plainly: a team went looking for fifteen years of trials on the thing being sold in the drip bag, and did not find them. That is not the same as the treatment having been tested and failed. It is the weaker and more common situation of it never having been properly tested at all.

The research that gets cited is about something else

Clinics do cite real science, and the science is real. It is mostly about two oral precursors, nicotinamide riboside and nicotinamide mononucleotide, which the body converts into NAD. Different molecules, taken by a different route, in trials that studied swallowing rather than infusing.

Nicotinamide riboside

An eight-week randomised, double-blind, placebo-controlled trial in overweight but otherwise healthy adults tested 100, 300 and 1,000 mg a day and reported dose-dependent increases in blood NAD (Scientific Reports, 2019). The NADPARK trial gave 1,000 mg a day or placebo to 30 newly diagnosed, treatment-naive Parkinson's patients for 30 days, reported it was well tolerated, and measured a significant but variable rise in cerebral NAD using phosphorus magnetic resonance spectroscopy (Cell Metabolism, 2022). A placebo-controlled pilot randomised 20 older adults with mild cognitive impairment to placebo or NR escalated to 1 g a day over ten weeks, with safety as the primary objective (GeroScience, 2024).

Nicotinamide mononucleotide

A ten-week randomised, placebo-controlled, double-blind trial in postmenopausal women with prediabetes who were overweight or obese measured insulin-stimulated glucose disposal using a hyperinsulinemic-euglycemic clamp, and reported increased muscle insulin sensitivity (Science, 2021).

Those are the doses and populations those studies used. They are not recommendations, and none of them involved an injection or a drip.

Why the claims sound so much stronger than the trials

Of the 113 studies the 2026 review identified, 80 were in rodents. In those models NAD augmentation was frequently associated with improvements across metabolic, mitochondrial, inflammatory and functional outcomes, though the review notes effects varied by model and endpoint.

That is where the dramatic language comes from. Marketing copy tends to borrow the rodent results and the human safety data, then present the combination as if it were human efficacy. In people, the same review found that oral NR and NMN consistently hit their biochemical target, raising NAD-related metabolites in blood or cells, and were generally well tolerated over weeks to months, but that effects on functional, metabolic, vascular and other healthspan outcomes were heterogeneous and often null or specific to a single endpoint.

The review's own summary is that NAD augmentation shows clear biological activity while clinical effectiveness for anti-aging or wellness outcomes remains inconclusive, and that larger, longer randomised trials with prespecified meaningful endpoints are needed, particularly for parenteral approaches.

Drip, injection or capsule

The three routes are not interchangeable, and the difference is the reason the evidence does not transfer.

• Intravenous. The infusion most clinics sell, typically run slowly over an hour or more. Going too fast is widely reported to cause chest tightness, flushing and nausea, which is why the drip takes as long as it does.
• Subcutaneous or intramuscular injection. Sold for use between clinic visits. This is the route the 2026 review specifically reported having no outcomes trials.
• Oral precursors. NR and NMN capsules, which is what nearly all the human trial evidence actually studied, and which are regulated as dietary supplements rather than drugs.

What to ask a clinic

• Is this NAD itself, or a precursor such as NR or NMN?
• Which published trial is the claimed benefit taken from, and did that trial use this route?
• Was the study in people or in rodents, and how many participants did it enrol?
• Who compounded the preparation, and is that pharmacy licensed?
• What does the full course cost, not just the first session?

Clinics offering NAD are listed in the directory with their own contact details, and the cost guide covers what usually drives the price.

Common questions