NAD+ side effects: What studies report for injections, drops, and nasal spray

NAD+ (nicotinamide adenine dinucleotide) is a coenzyme found in every cell in the body. Compounded NAD+ is prescribed as an injection, oral drops, and a nasal spray. It is not FDA-approved, and human safety research on it is thin. This article covers what published studies actually report, where the gaps are, and who should talk to a provider before starting. It is educational and not medical advice.

What NAD+ is, and where it stands with the FDA

NAD+ is a coenzyme: a helper molecule that many enzymes need to carry out chemical reactions inside cells. It is not a peptide.

There is no FDA-approved NAD+ drug, so NAD+ products are compounded. The FDA does not review compounded drugs for safety, effectiveness, or quality [1].

NAD+'s status for compounding is also unsettled. In 2019, after review and consultation with its Pharmacy Compounding Advisory Committee, the FDA proposed not adding NAD to the list of bulk substances allowed for compounding under section 503A [2]. As of May 2026, the FDA still lists NAD among bulk drug substances "under evaluation" [3]. No final decision has been made.

What has been studied

Two small human studies of directly administered NAD+ are the most relevant. Both used IV infusion, a route Luvo does not offer, so they speak only indirectly to injections, drops, or spray.

A slow, six-hour infusion. In a 2019 pilot study, eight healthy men received 750 mg of NAD+ by IV over six hours, while three received saline [4]. The researchers observed no adverse events during the infusion [4]. Some liver-related blood markers shifted at the eight-hour mark, but the authors did not consider the changes clinically significant [4]. The study was partly funded by an NAD+ research organization, and one author directs a clinic that provides IV NAD+ [4].

A self-paced infusion. A 2026 retrospective review looked at records from a commercial wellness setting where clients controlled their own infusion rate [5]. All six people who received 500 mg of IV NAD+ reported moderate to severe abdominal cramping, diarrhea, nausea, vomiting, increased heart rate, throat pain, congestion, and chest pressure during the infusion [5]. These symptoms stopped once the infusion ended [5].

Read together, the two studies suggest that how quickly NAD+ enters the bloodstream may affect how it feels. Neither study was designed to prove that, and both were very small.

What is known by route

Injection under the skin or into muscle. We did not find published human studies reporting side effects for NAD+ given this way. Any injection can cause soreness, redness, or bruising where the needle went in, and your provider will explain what to watch for.

Oral drops. We did not find published human studies on side effects of oral NAD+ itself. Much of the oral research uses related molecules such as nicotinamide riboside, which is a different compound, so those results should not be assumed to apply.

Nasal spray. We did not find published human safety data for NAD+ nasal spray. Whether it causes nasal irritation, or more or fewer side effects than other routes, is not known.

Long-term use. None of the studies we found followed people using NAD+ for months or years. Long-term safety is unknown.

For how the three routes differ in practice, see NAD+ injection vs oral drops vs nasal spray.

Who should talk to a provider first

The studies above left out certain groups, which means there is no safety data for them:

• People who are pregnant (the 2026 review excluded them, and the 2019 study enrolled only men) [4, 5]
• People with a recent or family history of cancer [5]
• People with a history of liver or kidney failure [4]

These are not comprehensive lists of risks or contraindications; patients should review the prescribing information and discuss their medical history with their clinician.

Tell your provider about these and about any other conditions and medications before starting. Luvo does not run labs or test NAD+ levels.

When to stop and call a provider

Stop and contact your provider if you notice chest pain or pressure, a racing or irregular heartbeat, trouble breathing, swelling of the face or throat, or vomiting that keeps you from holding down fluids.

Like any prescription treatment, compounded NAD+ carries possible risks and side effects, and your provider will review them with you before anything is prescribed. For background on what NAD+ is and how it is used, see NAD+ therapy explained.

Common questions

Is NAD+ safe long term?
That is not known. The published human studies are small and short [4, 5].

Does the nasal spray have fewer side effects?
We found no published data comparing routes, so there is no evidence either way. See the NAD+ nasal spray page for how it is prescribed.

What is the "NAD flush"?
It is not a medical term. People use it informally to describe how IV NAD+ can feel. The 2026 review describes cramping, nausea, chest pressure, and a faster heart rate during infusion that stopped when the infusion ended [5].

Next steps

If any of this sounds like what you are dealing with, the next step is a conversation with a licensed provider who can review your history and decide whether treatment makes sense for you. Nothing is prescribed or shipped without that review. Any medication preference you indicate is only a starting point for discussion. A licensed clinician independently determines whether prescription treatment is medically appropriate and, if so, which medication, dose, and treatment plan are appropriate based on your clinical evaluation.

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