Search the benefits of NAD⁺ injections and you will be told: more energy, sharper focus, better sleep, faster recovery, slower aging. The lists are remarkably consistent from seller to seller, which is worth noticing, because none of them come from a trial of an injection.
What we searched for, and did not find
We went looking for the study. On September 13, 2026 we ran four searches against PubMed. A search for NAD+ injection randomized controlled trial energy fatigue returned zero results. A search for subcutaneous NAD+ injection humans trial returned six, none of which concern NAD⁺ at all — they are about continuous glucose monitoring, subcutaneous immunoglobulin and interleukin-2. A search for subcutaneous nicotinamide adenine dinucleotide clinical trial returned thirteen, again none about injected NAD⁺ in people.
This is not us being unable to find something. A 2026 PRISMA-guided systematic review searched the literature from January 2010 to October 2025 and stated, in its own abstract, that no eligible outcomes trials evaluated intravenous or intramuscular NAD⁺ for anti-aging or wellness indications [1]. Formal reviewers went looking too, and came back with nothing to include.
What the heart-failure studies do and do not establish
Controlled NAD⁺ research is not absent across every indication. A 180-person IV trial in heart failure reported an improvement in ejection fraction, while its major-event result was not statistically significant[3]. In another 60-person heart-failure trial, differences in ejection fraction and NT-proBNP were not statistically significant[4]. Our heart-failure trial comparison explains those findings. Neither study tested routine subcutaneous wellness shots or establishes their advertised energy, focus or anti-aging benefits.
So where do the benefit lists come from?
From research on a different product. Oral precursors — nicotinamide riboside and nicotinamide mononucleotide — have been tested in randomized trials, and they reliably do one thing: raise blood NAD⁺. In a dose-ranging trial of 80 healthy middle-aged adults (n = 80), blood NAD⁺ rose significantly in every NMN group at day 30 and day 60, against both placebo and baseline (all p ≤ 0.001) [2].
That is a real result for a capsule. It is then carried across to a needle by an argument that goes: injections raise NAD⁺ more, so they must do more. Bypassing digestion changes delivery, but does not establish how much reaches relevant tissues or whether clinical outcomes improve.
And it is worth being precise about what even the capsule trials found. The same 2026 review reports that while oral NR and NMN consistently engage the biochemical target, their effects on functional, metabolic and vascular outcomes were “heterogeneous and often null or endpoint-specific” [1]. So the borrowed evidence is thinner than the borrowing implies — what the trials actually measured goes through it claim by claim.
A NAD⁺ shot has to clear two different evidence tests
A shot and an injection describe the same route here. First, a study must show what happens to NAD⁺ after that specific product is administered. Second, it must test whether that change improves the outcome being advertised. Passing the first test would not automatically pass the second. In controlled NR cognition studies, blood NAD⁺ rose without a demonstrated memory benefit.
A flush or other immediate sensation is not a validated sign of benefit. It can be an unwanted effect, and it does not establish improved energy, recovery or cognition. The practical shots guide covers questions about the experience; the side-effects review covers what to discuss with the prescriber.
The claims, one at a time
Energy. No controlled trial of injected NAD⁺ has measured it. NAD⁺ is genuinely central to cellular energy metabolism, which is why the claim feels obvious — but a molecule’s role in a pathway is not evidence that adding more of it makes a person feel energetic.
Focus and mental clarity. Not demonstrated for injections. Worth knowing: when cognition was measured, in a placebo-controlled trial of an oral precursor in older adults with mild cognitive impairment, it did not change.
Anti-aging. Not demonstrated in any format, at any dose, by any route. This is the claim the category is built on and the one with the least behind it.
Recovery and athletic performance. One NMN trial measured six-minute walking distance and found an improvement. That is an oral precursor, in a specific population, on a specific endpoint — not an injection, and not a general performance claim.
Hangover and addiction recovery. Widely marketed, particularly by IV clinics. No controlled outcome trials support it.
What an injection does do
It delivers more NAD⁺ than a capsule, and it costs several times more. Both of those are true and neither is in dispute. If you value bypassing digestion, a shot is the straightforward way to do that, and our rankings compare the sellers on what they disclose.
What we would ask you not to do is buy it expecting the list. Decide what you would need to see to call it working, decide in advance when you will check, and know that if you feel better, you will not be able to separate the drug from the several hundred dollars you spent expecting it to work — which is exactly why trials use placebo groups.
And if the benefits are what you are after rather than the format, the honest starting point is the one with the trials: an oral precursor, at roughly a quarter of the price.