NAD+ injections may cause injection-site pain, soreness, nausea, flushing or warmth, headache, dizziness, and other short-term reactions. Human research on injected NAD+ is still very limited, so we do not yet have reliable estimates for how common each side effect is or how safe repeated long-term use may be (1).

NAD+ can be given into a muscle, under the skin, or through an IV. These routes are not interchangeable, and much of the available safety research still comes from very small studies.

Key Takeaways:

• Human safety data on NAD+ injections is still limited, especially for repeated long-term use.

• Injection-site pain, soreness, tightness, and short-term systemic symptoms may occur.

• A small 2026 study directly tested 100 mg NAD+ by intramuscular and subcutaneous injection, but the groups included only four and six people (1).

• NAD+ IV therapy has produced more noticeable symptoms such as nausea, cramping, chest pressure, and increased heart rate in recent research (2).

• Compounded injectable NAD+ is not FDA-approved, and the FDA has raised concerns about unsuitable ingredients being used in some sterile NAD+ preparations (3).

What Are NAD+ Injections?

NAD+, or nicotinamide adenine dinucleotide, is a coenzyme found throughout the body. Cells use it in energy metabolism, DNA-related processes, and cellular signaling.

NAD+ injections attempt to deliver NAD+ without going through the digestive system.

You may see several forms offered:

• Intramuscular injections:NAD+ is injected into a muscle.

• Subcutaneous injections:NAD+ is placed into the fatty tissue beneath the skin.

• IV therapy:NAD+ enters the bloodstream through a vein over a longer period.

These approaches are marketed by wellness clinics for energy, mental clarity, recovery, and healthy aging.

The clinical evidence for those benefits remains limited. There is much stronger evidence showing that NAD+ plays important biological roles than there is showing that injecting extra NAD+ produces meaningful health benefits in otherwise healthy people.

What Are the Side Effects of NAD+ Injections?

We still do not have a large clinical trial that can give reliable percentages for common NAD+ injection side effects.

The best direct evidence is quite new.

A 2026 Phase 1 preprint included 45 adults ages 40 to 64 who received placebo, nicotinamide riboside, or NAD+ through intramuscular, intravenous, or subcutaneous administration.

Participants assigned to NAD+ received 100 mg once daily for three consecutive days. Only four people were in the intramuscular NAD+ group and six were in the subcutaneous NAD+ group (1).

Researchers reported no severe or unexpected adverse events attributed to the injections during this short trial. Vital signs also remained within normal ranges (1).

Because the NAD+ injection groups were so small and treatment lasted just three days, this study cannot establish the long-term safety of regular NAD+ shots.

It is also a preprint, which means it had not yet completed peer review at the time of writing.

Injection-Site Pain and Soreness

Pain, tenderness, burning, tightness, or soreness can occur after an injection.

Some of this comes from the injection itself rather than NAD+ specifically. A needle entering muscle or subcutaneous tissue can irritate the area.

The 2026 injection research collected participant experiences such as discomfort around administration, although the small NAD+ groups make it difficult to calculate meaningful side-effect rates for NAD+ itself (1).

Persistent redness, worsening swelling, drainage, severe pain, or warmth around an injection site deserves medical attention because those symptoms may point to infection or another injection-related complication.

Nausea and Stomach Discomfort

Nausea is widely reported by NAD+ clinics, but good data specifically measuring nausea after IM or subcutaneous NAD+ injections is sparse.

We have better evidence for intravenous NAD+.

A 2026 pilot study found that people receiving NAD+ IV infusions reported gastrointestinal symptoms including nausea, abdominal cramping, diarrhea, and vomiting during treatment (2).

That study involved IV therapy rather than an IM or subcutaneous shot, so those findings should not automatically be applied to every form of injected NAD+.

Headache or Dizziness

Headache and lightheadedness appear on many clinical descriptions of NAD+ injections.

At this point, however, large controlled trials have not established how frequently NAD+ injections cause either symptom.

Dizziness after any injection can also have causes unrelated to the substance itself. Anxiety, pain, fasting, dehydration, or a vasovagal response to needles can make someone feel faint.

A new symptom that is severe, persistent, or recurring after each dose is worth discussing with the prescribing clinician.

Flushing or Feeling Warm

Some people describe warmth or flushing shortly after receiving NAD+.

This symptom also appears in reports from NAD+ IV therapy.

It should not be confused with the classic "niacin flush" caused by nicotinic acid. NAD+, nicotinic acid, NMN, and NR are related to NAD metabolism, but they are different compounds with different safety profiles.

Research has not established that flushing from an NAD+ injection comes from the same mechanism as a niacin flush.

Muscle Tightness or Cramping

Muscle discomfort may happen around an injection, especially with intramuscular administration.

Direct IV NAD+ research has also reported cramping during treatment.

In one 2026 study comparing NAD+ IV with intravenous NR, participants receiving NAD+ reported moderate to severe gastrointestinal symptoms, increased heart rate, chest pressure, and other discomfort during infusions (2).

Those reactions stopped after the infusion ended.

Again, an IV infusion is different from a small IM or subcutaneous injection. This evidence is useful for understanding NAD+ tolerability, but it cannot tell us the exact risk from a shot.

Are Serious NAD+ Injection Side Effects Possible?

Serious reactions have not been well characterized because direct clinical studies are small.

Any injectable product can introduce risks that oral supplements do not have.

These include:

• Infection

• Contamination

• Allergic reactions

• Bleeding or bruising

• Tissue irritation

• Incorrect injection placement

• Problems related to product sterility or preparation

Severe chest pain, difficulty breathing, fainting, facial or throat swelling, widespread hives, or severe weakness after an injection requires prompt medical attention.

Are NAD+ Injections FDA-Approved?

Compounded NAD+ injections are not FDA-approved treatments for anti-aging, energy, mental clarity, or other wellness claims.

Compounded products can be prescribed in certain circumstances, but the FDA does not review them for safety, effectiveness, and manufacturing quality in the same way it reviews approved medications.

There is another concern worth knowing about.

The FDA has specifically warned compounders about using inappropriate ingredients to make sterile NAD+ products. The agency reported being aware of compounders using food-grade NAD+ to prepare intravenous products and warned that unsuitable material may carry microbial or endotoxin contamination risks (3).

This does not mean every compounded NAD+ injection is contaminated.

It does mean the source, preparation, sterility standards, and pharmacy behind an injectable product deserve serious attention.

What About NAD+ IV Side Effects?

NAD+ IV therapy has more direct human tolerability data than NAD+ shots.

A 2026 pilot study followed people receiving commercially administered NAD+ or NR IV therapy over 30 days.

Participants in the NAD+ group reported symptoms including:

• Nausea

• Vomiting

• Abdominal cramping

• Diarrhea

• Increased heart rate

• Chest pressure

• Throat discomfort

• Congestion

The symptoms stopped when the infusion ended (2).

The average NAD+ infusion also lasted about 97 minutes, compared with approximately 37 minutes in the NR group, partly because people receiving NAD+ needed slower administration due to discomfort (2).

Only six people received NAD+, so these results should be viewed as preliminary.

Still, the study gives us something valuable that was missing from much of the older NAD literature: direct human information about what people experienced during commercially administered NAD+ therapy.

Does NAD+ Injection Work Better Than Oral Supplements?

We do not have enough comparative human research to say that NAD+ injections work better than oral NAD+ precursors.

Injecting something bypasses digestion, but that alone does not prove greater health benefits.

Researchers are still working out what happens to extracellular NAD+ after administration and how much intact NAD+ reaches different tissues and cells.

For oral supplementation, researchers have focused more heavily on NAD+ precursors such as NMN and nicotinamide riboside, or NR.

These compounds enter NAD metabolism and can raise NAD-related biomarkers in humans.

For example, an eight-week randomized trial involving 140 adults found that 100 mg, 300 mg, and 1,000 mg of NR increased whole-blood NAD+ by approximately 22%, 51%, and 142%, respectively. Adverse-event rates did not significantly differ from placebo (4).

NMN also has controlled human safety data. One study gave 1,250 mg of NMN daily to 31 healthy adults for four weeks and did not find clinically concerning changes across the safety measures examined (5).

Neither result proves that taking NMN or NR extends lifespan or prevents age-related disease.

They do show that oral NAD+ precursors have been studied in larger controlled groups than direct NAD+ injections.

NAD+ Injections vs NMN and NR

Here is a simple comparison of the current research:

The best choice cannot be decided simply by which option reaches the bloodstream fastest.

Convenience, quality control, cost, clinical evidence, personal health, and the reason someone wants NAD support all come into play.

Who Should Be Careful With NAD+ Injections?

Research has not established a complete list of people who should never receive NAD+ injections.

Several groups have little direct safety data, including:

• Pregnant or breastfeeding people

• Children and adolescents

• People with significant liver or kidney conditions

• People with complex medical conditions

• People receiving cancer treatment

• Anyone taking multiple prescription medications

A healthcare professional can review medications, medical history, allergies, and the formulation being used before treatment.

That becomes even more important when the product is compounded or injected at home.

How Long Do NAD+ Injection Side Effects Last?

There is no well-established timeline for NAD+ injection side effects.

Short-term injection-site discomfort may settle as the tissue recovers, while systemic symptoms can vary from person to person.

The direct NAD+ injection studies available today are too small to give a reliable answer such as "side effects last two hours" or "symptoms disappear within one day."

For NAD+ IV therapy, the 2026 pilot study found that infusion-related symptoms resolved after administration ended (2).

If symptoms continue, get worse, or return after every injection, speak with the prescribing clinician rather than assuming that the reaction is a normal part of NAD+ therapy.

Are Oral NAD+ Precursors an Alternative?

For someone interested in NAD support but not interested in injections, NMN and NR are two oral options with considerably more human research behind them.

Both are molecules the body can use within NAD+ metabolism.

Oral supplementation also avoids needle-related issues such as injection-site irritation, contamination, and improper administration.

That does not make NMN or NR risk-free, and research into their long-term effects is still developing.

At Omre, we use NMN as the NAD+ precursor in our NMN + Resveratrol formula rather than injectable NAD+.

Our approach focuses on a clearly disclosed dose, third-party testing, and an oral format designed for consistent daily use.

You can learn more about Omre NMN + Resveratroland the research behind its ingredients.

Final Words

NAD+ injections are getting plenty of attention, but the clinical evidence has not caught up with their popularity.

The first direct studies of intramuscular and subcutaneous NAD+ are small and short. Early results have not identified major safety problems in those limited groups, but they cannot tell us how regular NAD+ injections affect hundreds or thousands of people over months or years.

IV research gives us a little more information and shows that direct NAD+ administration can produce noticeable short-term symptoms.

If you are considering NAD+ injections, pay attention to the exact formulation, how it will be administered, who prepared it, and who is providing the treatment. 

The science behind NAD metabolism is interesting. The science behind repeated NAD+ injections is still much younger.

FAQs

What are the most common side effects of NAD+ injections?

Injection-site pain or soreness, nausea, headache, dizziness, warmth, and muscle discomfort are reported with NAD+ therapy. Good clinical data is still too limited to give reliable percentages for these reactions after IM or subcutaneous NAD+ injections.

Can NAD+ injections make you feel sick?

Some people report nausea or stomach discomfort after NAD+ administration. Nausea, vomiting, and abdominal cramping have also been documented during NAD+ IV therapy, although IV findings cannot be directly applied to smaller injections.

Are NAD+ injections FDA-approved?

Compounded NAD+ injections are not FDA-approved for anti-aging, energy, focus, or other wellness uses. The FDA has also warned compounders about using inappropriate food-grade NAD+ ingredients when preparing sterile products (3).

Can NAD+ injections cause chest tightness?

Chest pressure has been reported during NAD+ IV therapy in a small human study (2). There is not enough research to know how frequently this happens with IM or subcutaneous NAD+ injections.

Are NAD+ injections better than NMN supplements?

There is not enough comparative human evidence to say NAD+ injections are better. NMN has more published controlled human research on oral use, while direct NAD+ injection research remains limited.

References

1. Nkrumah-Elie Y, et al. (2026). Preliminary Safety Analysis of Two Pilot Clinical Trials Involving Injections of Niagen^®, Nicotinamide Riboside Chloride. medRxiv. Preprint.

2. Reyna K, et al. (2026). Intravenous infusion of nicotinamide adenine dinucleotide (NAD+) versus nicotinamide riboside (NR): a retrospective tolerability pilot study in a real-world setting. Frontiers in Aging.

3. U.S. Food and Drug Administration. FDA reminds compounders to use ingredients suitable for sterile compounding.

4. Conze D, et al. (2019). Safety and Metabolism of Long-term Administration of NIAGEN in a Randomized, Double-Blind, Placebo-Controlled Clinical Trial of Healthy Overweight Adults. Scientific Reports.

5. Fukamizu Y, et al. (2022). Safety evaluation of β-nicotinamide mononucleotide oral administration in healthy adult men and women. Scientific Reports.