NAD+ as nasal spray and injection

What NAD+ as nasal spray and injection is

NAD+ (nicotinamide adenine dinucleotide) is a coenzyme that every cell needs for energy metabolism and that enzymes such as sirtuins and PARP consume. In the longevity field there are three ways to raise its level: the precursors NMN and NR taken by mouth, the intravenous infusion and, the subject here, NAD+ sprayed directly into the nose or given with a small injection under the skin.

This page covers only the nasal spray and the injection. What has been shown for the precursors, such as the rise of NAD+ in the blood after NR, cannot be transferred: it is a different substance on a different route. What is rated is the state of knowledge, and for both dosage forms it is thin.

How it is supposed to work

With the nasal spray, the idea is to bring NAD+ via the olfactory mucosa directly toward the brain. In rats, the NAD+ content in the brain did indeed rise after intranasal administration. With the injection under the skin, NAD+ is supposed to bypass the digestive tract, where it would be broken down.

What remains open is how much of it reaches the cells intact. Infused intravenously in humans, it disappeared completely from the blood plasma within the first 2 hours, and the breakdown products were consistent with enzymes that break down NAD+ outside the cells. Whether the nose or the skin changes anything about this has not been measured in humans.

What the studies show

Nkrumah-Elie 2026: three routes, a handful of people each

A preprint from 2026, that is, not yet peer-reviewed, summarizes two pilot studies. In the first, 45 people were divided into nine groups: placebo, NR or NAD+, each into the muscle, into the vein or under the skin, once daily on 3 days. 6 people received NAD+ under the skin. Vital signs, blood values, participant reports and side effects were measured, not any effect on energy or performance. All participants stayed in; the injections were associated with discomfort but well tolerated. The second study tested only NR in 39 people; there, 45.9 percent reported pain lasting longer than 2 minutes after the injection. A registered study with the same design of NR, NAD+ and placebo on three routes (NCT06919328) names pain at the injection site as its primary outcome.

Grant 2019: what happens to NAD+ in the blood

In a pilot study, healthy people received NAD+ intravenously for 6 hours. In the first 2 hours, neither NAD+ in the plasma nor any of its breakdown products rose; the administered NAD+ was rapidly and completely removed from the plasma. The breakdown products pointed to enzymes that cleave NAD+ outside the cells. After 6 hours, NAD+ and methylnicotinamide were increasingly excreted in the urine. The study concerns the vein, not the nose or the skin. But it shows that administered NAD+ does not simply arrive in the cells as NAD+.

Ying 2007: rats, stroke, nose

In rats with a temporarily occluded brain artery, intranasal NAD+ raised the NAD+ content in the brain. Given two hours after the onset of the circulatory disturbance, it reduced infarct size after 24 and 72 hours and alleviated the neurological deficits. Nicotinamide given by the same route had no effect. This is an acute model in animals, not an indication of an effect in healthy people.

Yoo 2026: mice without a sense of smell

In mice whose olfactory mucosa had been chemically damaged, intranasal NAD+ improved the sense of smell and the repair of the mucosa. In cell culture, NAD+ promoted the maturation of human olfactory stem cells into olfactory nerve cells. The paper is the first trace of a possible medical application in the nose, but it has not been tested in humans.

Where the data stop

• Any effect in humans. For energy, concentration, sleep, recovery or aging there is no study with a control group, neither for the nasal spray nor for the injection.
• The nasal spray at all. There is not a single study in humans, not even on tolerability on the nasal mucosa or on whether appreciable amounts are absorbed.
• Whether NAD+ reaches the cells. All that has been measured is that NAD+ given intravenously is rapidly broken down in the plasma. For the skin and the nose, such measurements are lacking.
• Transferability from NMN, NR and infusion. The data on the precursors and on the infusion concern other substances or other routes and do not automatically apply to the nasal spray and the injection.
• Longer use. The longest observation of NAD+ under the skin covers 3 days in 6 people.

Status, approval and legal

In Germany and the EU, no approved medicine containing NAD+ as a nasal spray or injection was found during research. Nasal sprays and injections are not foods, because under EU law foods are products intended to be ingested. Products intended to influence bodily functions are medicines; without approval they may not be placed on the market under § 21 of the German Medicines Act (Arzneimittelgesetz).

It is different when swallowed: the European Commission’s Novel Food Catalogue classifies NAD+ in food supplements as not novel (entry of February 1, 2024). A capsule containing NAD+ therefore does not need novel food authorization, but a nasal spray or an injection does not fall under food law at all.

Safety

For the nasal spray there are no safety data in humans. For the injection under the skin they come from a preprint with 6 people over 3 days: no unexpected side effects attributable to the injection, but discomfort at the injection site. In the follow-up study with the related NR, 45.9 percent complained of pain lasting longer than 2 minutes after the injection and 43.2 percent of muscle soreness or tension.

On top of this come the risks of the route itself. Products from the gray market are not tested for purity and sterility; self-mixed solutions and injections carry the risk of infections at the injection site. Long-term and interaction data are completely lacking.

Sources

• Nkrumah-Elie Y et al., medRxiv 2026 (preprint) – preliminary safety analysis of two pilot studies with subcutaneous, intramuscular and intravenous injections of NR and NAD+
• Grant R et al., Front Aging Neurosci 2019 – NAD+ metabolome in plasma and urine during a 6-hour NAD+ infusion, pilot study
• Ying W et al., Front Biosci 2007 – intranasal NAD+ reduces brain damage in rats after transient ischemia
• Yoo SH et al., Exp Mol Med 2026 – intranasal NAD+ in loss of smell, mouse and human olfactory stem cells
• ClinicalTrials.gov NCT06919328 – uptake and tolerability of injected NR compared with NAD+, randomized, blinded
• ClinicalTrials.gov NCT07251608 – safety study with repeated subcutaneous and intramuscular injections of NR over 100 days
• European Commission, Novel Food Catalogue – Nicotinamide adenine dinucleotide (NAD+): not novel in food supplements
• Regulation (EC) No 178/2002, Article 2 – definition of food
• German Medicines Act (AMG) § 21 – marketing authorization requirement