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.

What happens to NAD once it is in a vein

There is one published human study of what an NAD infusion actually does inside the body, and it is worth knowing about because almost nobody selling the drip mentions it. Researchers infused NAD intravenously for six hours at 3 micromoles a minute and sampled plasma and urine throughout (Frontiers in Aging Neuroscience, 2019). It measured where the molecule went. It did not measure whether anyone felt better.

Put plainly: for the first stretch of a drip, the bloodstream does not show more NAD in it. The body pulls the molecule out and takes it apart about as fast as it arrives, and some of it leaves in urine. That is a pharmacokinetic result, not a verdict on whether the treatment helps anyone — but it is the specific thing the 2026 systematic review meant when it classed this study as contextual evidence only, because it carried no clinical outcomes.

A 2026 review in Molecular Biology Reports, which paired a literature review with mathematical modeling, reached the same place from another direction: it reported that intravenous NAD is less well characterized than the oral precursors and lacks robust clinical validation, and that NAD responses are nonlinear, shaped by dose, age, metabolic state and route, with feedback and saturation rather than a simple more-in, more-out relationship.

Drip, shot, or capsule: what each one actually has behind it

These three are sold almost interchangeably and the evidence behind them is not interchangeable at all.

The pattern in that last column is the whole story. The route with the most evidence behind it is the one nobody markets, and the two routes clinics sell are the two with no outcome trials at all.

The three also sit in different regulatory places, which is easy to miss when a clinic menu lists them side by side. The infusion and the injection are preparations a pharmacy compounds. The capsules are sold as dietary supplements, a different route entirely from drug approval, and nicotinamide riboside has been the subject of dietary-ingredient notifications on that basis. The injection is the one usually sold for use between visits, which is also the one the 2026 review reported no eligible outcome trials for.

What is known about side effects

Less than you would want, and the honest reason is that a treatment which has not been through outcome trials has also not been through systematic adverse-event collection. What exists falls into two piles.

For the oral precursors, where the trials are, the 2026 review reported that NR and NMN were generally well tolerated across weeks to months of dosing. The eight-week trial of 100, 300 and 1,000 mg of NR a day in overweight adults, the 30-day NADPARK trial at 1,000 mg a day, and the ten-week pilot escalating to 1 g a day in older adults with mild cognitive impairment all had safety or tolerability among their objectives and none reported a safety signal that stopped them.

For the infusion, there is no equivalent body of data, and what circulates instead is clinical convention: chest tightness, flushing, cramping and nausea when the drip runs quickly, easing when the rate is slowed, which is why a session is commonly scheduled over an hour or more rather than minutes. That is widely reported by clinics and by people who have had it, and it is not the same kind of evidence as a recorded adverse-event table. Anyone weighing this should also know that infusion preparations are typically compounded, so what is in the bag depends on the pharmacy that made it.

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.

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