NAD+ can be given by IV infusion, injection under the skin or nasal spray, but human data on these routes are small, short and mostly limited to blood levels and tolerability. No route has been shown to improve health outcomes in controlled trials.
NAD+ is sold as an IV drip, as an injection under the skin and as a nasal spray, and each route is often described as the "best" way to raise NAD+. The honest answer is that no route has been shown in controlled human trials to improve energy, aging or any health outcome. The IV route has a handful of small pilot studies that measured blood levels and tolerability; published human data for subcutaneous injection and nasal spray are thinner still. All three are compounded preparations, which are not FDA-approved.
| Route | How it is given | What published human data show | Main open questions |
|---|---|---|---|
| IV infusion | Slow drip into a vein in a clinic | Small pilot studies of blood levels and tolerability | How much reaches cells; why infusions feel uncomfortable for some people |
| Subcutaneous injection | Small injection under the skin, often at home | Very limited peer-reviewed data for NAD+ itself | Absorption, time course and outcomes |
| Nasal spray | Metered spray into the nose | No published human measurements we could find | How much is absorbed, and where it goes |
The appeal of non-oral routes is the idea that delivering NAD+ directly avoids digestion. That idea is reasonable to test, but a reasonable idea is not the same as evidence that it works.
The most cited IV study is a 2019 pilot by Grant and colleagues in Frontiers in Aging Neuroscience. It enrolled 11 men aged 30 to 55: eight received NAD+ over six hours and three received saline. Plasma NAD+ showed a significant increase (398 percent) only at the six-hour time point. The authors concluded that infused NAD+ was rapidly removed from plasma for at least the first two hours, consistent with enzymes that break it down. They observed no adverse events during the infusion in either group. The study was very small, the authors noted that the low sample number limited its sensitivity, and it was partly funded by a company connected to IV NAD+ therapy.
A second study, posted in 2024 as a medRxiv preprint by Hawkins and colleagues, has not been peer reviewed. It compared a single IV infusion of NAD+ with IV nicotinamide riboside (NR, a precursor), oral NR and saline in healthy adults aged 40 and older. Compared with IV NAD+, IV NR was associated with fewer and less severe adverse experiences during the infusion, and its mean tolerable infusion time was 75 percent shorter. The IV NAD+ group showed an increase in white blood cell and neutrophil counts, which the authors suggested may reflect an inflammatory response. At three hours, blood NAD+ was significantly higher with IV NR than with IV NAD+. Several authors are affiliated with the company that makes the NR product tested, which is worth keeping in mind.
Neither study tested whether IV NAD+ changes how people feel or function over time.
Subcutaneous NAD+ injections are prescribed through compounding pharmacies, yet in preparing this article we did not find peer-reviewed controlled trials that measured how injected NAD+ is absorbed, how long it stays elevated, or whether it improves any outcome in healthy adults. That gap does not mean injections are harmful or ineffective. It means the evidence needed to say either has not been published.
For context, the much larger body of research on oral NAD+ precursors shows how hard this question is to answer. A 2023 review by Freeberg and colleagues in the Journals of Gerontology concluded that supplementation with these compounds is safe, tolerable and can raise NAD+ and related metabolites, but that dosing regimens and study durations vary greatly and small sample sizes limit what can be concluded about physiological benefits. If the oral evidence is still unsettled, the injectable evidence is further behind.
Nasal sprays are marketed as needle-free and sometimes as a way to reach the brain. A 2020 review of nose-to-brain delivery by Trevino and colleagues explains why that claim is hard to evaluate:
None of these points are specific to NAD+, and none prove that a nasal spray does nothing. They explain why direct measurements in people are needed, and we did not find a published human study that provides them for intranasal NAD+.
Oral precursors are not the same thing as NAD+ itself, but they are the best-studied way to raise NAD+ in people. In a 2018 placebo-controlled trial in Nature Communications, Martens and colleagues found that oral NR was well tolerated in healthy middle-aged and older adults and raised NAD+ in blood cells by about 60 percent compared with placebo. As the Freeberg review points out, the harder question is whether raising this blood marker improves physiological function, and that remains unclear. For the broader picture of what NAD+ does in cells, see our guide NAD+ explained.
NAD+ injections and nasal sprays, including those available through NewDay Wellness, are compounded medications. According to the FDA, compounded drugs are not FDA-approved, which means the agency does not review their safety, effectiveness or quality before they are marketed. The FDA also notes that compounded drugs can serve an important medical need for some patients. Your prescriber sets any dosing and route; this article does not recommend one.
No route has been shown to work better than another for health outcomes, because no controlled trials have compared them on outcomes that matter to people. The small IV studies measured blood levels and comfort. Subcutaneous and nasal routes have even less published human data.
No. NAD+ nasal sprays are compounded preparations, and compounded drugs are not FDA-approved. The FDA does not review them for safety, effectiveness or quality before they are sold.
In a 2024 preprint that has not yet been peer reviewed, IV NAD+ was associated with more and more severe adverse experiences during infusion than an IV NAD+ precursor, and it required a longer infusion time to be tolerated. Why this happens is not fully understood, and individual experiences vary.
A blood test can show NAD+ or related metabolites, but a higher blood level has not been shown to translate into a specific health benefit. The 2023 Freeberg review describes the clinical evidence that raising NAD+ improves physiological function as unclear. Ask your provider what any test can and cannot tell you.
If you are considering NAD+ in any form, a licensed provider can walk through the current evidence for each route, review your medications and health history, and help you decide whether a compounded product is reasonable for you. If you have a reaction that feels severe, such as trouble breathing or chest pain, call 911. This article is educational and does not determine eligibility for any treatment.
Written by the NewDay Wellness editorial team from the sources above and checked against them before publication, and medically reviewed by Dr. Sean Arora and Dr. Shannon Arora of Arora Health & Aesthetics; see our editorial standards. This article is educational and does not diagnose conditions, establish eligibility for any medication, or replace care from a licensed provider. Compounded medications are not FDA-approved.
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