Quick answer: a NAD injection delivers NAD+ (nicotinamide adenine dinucleotide) under the skin, into a muscle or into a vein. A 6-hour IV infusion raised blood NAD+ in a small pilot, but a 2026 systematic review found no trials showing that injected or IV NAD+ improves any anti-aging or wellness outcome.[1][3] Common side effects during IV drips are nausea, chest pressure, flushing and a faster heart rate.[2][4]
This guide covers the types of NAD+ injections, what human studies found, side effects, contamination problems, doses that have been studied and regulatory status. For background on the molecule itself, see our NAD+ profile and the NAD+ topic hub. For the amounts used in studies, see our NAD+ dosage guide.
What NAD+ is, and why people inject it
NAD+ is a coenzyme, a helper molecule present in all cells, and the body can make it from niacin (vitamin B3).[1] It is not a peptide, though it is often sold by the same clinics. It is involved in energy metabolism, mitochondrial function and DNA repair.[4] The appeal of NAD+ boosting rests on the idea that NAD+ declines with age.[3]
That premise is now in doubt. A 2026 study measured whole-blood NAD+ in seven separate groups of people and found it stayed remarkably stable with age and across lifestyle interventions, changing only with nicotinamide riboside supplementation.[9]
Types of NAD+ injections
| Type | How it is given | Published human data |
|---|---|---|
| IV drip | Slow infusion into a vein, often over 1 to 6 hours | Small pilot and clinic review[1][2] |
| IV push | Small dose pushed into a vein over minutes | Registered trial only, no results[8] |
| Intramuscular (IM) shot | Into a muscle | Registered trial only, no results[8] |
| Subcutaneous (SC) shot | Under the skin | Registered trial only, no results[8] |
The most searched option, a quick NAD+ shot under the skin, is the one with the least published evidence.
NAD+ injection benefits: what the evidence shows
Raising blood NAD+
In a 2019 Australian-US pilot, 8 healthy men received 750 mg of NAD+ by IV over 6 hours. Surprisingly, blood NAD+ did not change for the first 2 hours, because the body cleared it as fast as it went in. Levels rose later, and NAD+ and its breakdown products appeared in urine.[1]
Health outcomes
- No anti-aging outcome trials: a 2026 systematic review of 33 human intervention studies found no eligible trials testing IV or intramuscular NAD+ itself for anti-aging or wellness outcomes.[3]
- Evidence called preliminary: a second 2026 review concluded that human evidence on IV NAD+ is sparse, mostly small uncontrolled studies and case reports, and insufficient to support routine clinical or wellness use.[4]
- “Experimental intervention”: a 2026 critical review of IV longevity therapy, including NAD+, said placebo-controlled trials are scarce and underpowered, and that it should be regarded as experimental.[5]
Heart failure trials in China
Two hospital trials used much lower doses than wellness clinics, alongside standard heart failure drugs:
- 180 patients, 10 mg of IV NAD+ daily for 7 days: heart pumping (ejection fraction) was modestly better at 1 month (45.4% vs 42.4%). Trends toward fewer hospitalizations were not statistically significant.[6]
- 60 older patients, 50 mg daily for 7 days: improvements in heart function markers were not statistically significant.[7]
These are early results in a specific disease, not evidence for energy or aging in healthy people.
NAD+ injection side effects
During IV infusions
A 2026 review of wellness-clinic records compared four daily 500 mg IV infusions of NAD+ with nicotinamide riboside (NR):[2]
- People on NAD+ reported moderate to severe stomach symptoms, a faster heart rate and chest pressure during infusions.
- Symptoms stopped when the infusion ended.
- Because of symptoms, NAD+ infusions took an average of 97 minutes, versus 37 minutes for NR.
- HDL (“good”) cholesterol fell in the NAD+ group; liver, kidney and thyroid markers did not change.
The authors worked for the clinic chain that gave the infusions. A separate 2026 review lists nausea, cramping, flushing and chest discomfort as reported adverse effects, and notes that long-term safety data are lacking.[4]
Speed appears to matter. In the 2019 pilot, no adverse events were observed during a slow 6-hour infusion.[1] That is an observation across small studies, not a tested comparison.
Shots under the skin or into muscle
No published study has reported side effects of NAD+ given under the skin or into a muscle. A trial comparing discomfort from 100 mg NAD+ injected under the skin, into muscle and by IV push was registered, but no results have been posted.[8] For general signs of a problem at an injection site, see our guide to injection-site reactions.
Contamination and recalls
- Food-grade ingredients: in October 2024, FDA warned that some compounders were making IV NAD+ from food-grade NAD+, which carries a high risk of microbial and endotoxin contamination. FDA had received reports of severe chills, shaking, vomiting and fatigue after NAD+ injections, some needing medical treatment.[10]
- Recalls: FDA enforcement reports list several recalls of compounded NAD+ injections since 2022, mostly for lack of assurance of sterility. One October 2025 recall was Class I, FDA’s most serious category, for elevated bacterial endotoxin levels.[11]
For how product sources differ, see compounded vs research-grade peptides.
NAD+ injection doses that have been studied
There is no approved or established dose. These are the amounts in published or registered human studies:
| Setting | Dose |
|---|---|
| Pilot in healthy men | 750 mg IV over 6 hours, once[1] |
| Wellness-clinic review | 500 mg IV daily for 4 days[2] |
| Heart failure trial | 10 mg IV daily for 7 days[6] |
| Older heart failure patients | 50 mg IV daily for 7 days[7] |
| Registered injection trial | 100 mg under the skin, into muscle or IV push[8] |
These are research amounts, not recommendations. A clinician sets any dose, and the 2026 narrative review said optimal dosing cannot currently be established.[4]
Is NAD+ approved or legal?
- Not FDA-approved as a drug for any condition.
- Compounding: as of May 2026, FDA lists NAD in category 1, bulk substances still under evaluation for use by compounding pharmacies.[12]
- Earlier FDA view: in a 2019 proposed rule, FDA proposed not adding NAD to the compounding list. It said NAD degrades with light, moisture and room temperature, that safety data were insufficient, and that its advisory committee had voted against it in 2017.[13] NAD has remained under evaluation since then.[12]
Who should be cautious
- People with heart rhythm problems or chest pain, given the faster heart rate and chest pressure reported during infusions.[2]
- People who are pregnant or breastfeeding, as no safety data exist.
- Anyone offered NAD+ from an unknown source, given FDA’s contamination warnings.[10]
Questions to ask a clinician
- What outcome do you expect, and what evidence supports it?
- Where is the NAD+ made, and is it pharmaceutical grade and sterility tested?
- How fast will the infusion run, and what happens if I feel chest pressure?
- Would an oral precursor like NMN or NR be a better-studied option?
NAD+ is often paired with MOTS-c; see our MOTS-c dosage guide and our overviews of mitochondrial peptides research and the best peptides for longevity.
