Short answer: NAD+ is not an exotic peptide; it is a molecule every cell uses. That does not make injecting it side-effect free. The best-documented effects come from IV clinics: during the infusion, people commonly report nausea, abdominal cramping, chest pressure, a racing heart and flushing, and these usually fade when the drip is slowed or stopped. A 2026 clinic study found every NAD+ client reported at least one of these symptoms. Longer-term human safety data for repeated injections is close to non-existent. Here is what is known.
What NAD+ is and why people inject it
Nicotinamide adenine dinucleotide (NAD+) is a coenzyme that cells use for energy metabolism and DNA repair. Tissue levels fall with age in animal and some human studies, which is why it became a longevity target. Taken by mouth, NAD+ is largely broken down before it reaches the blood, so precursors (NMN, NR) are the usual oral route. Injections and IV drips are attempts to bypass that. For the broader research picture, see NAD+ in Canada: research guide.
The infusion side effects, measured
A 2026 retrospective study in Frontiers in Aging reviewed clinic records for clients who received 500 mg of IV NAD+ or nicotinamide riboside (NR) daily for four days, with a 30-day follow-up. It is small, but it is the most direct look at what people actually experience.
| IV NAD+ (n=6) | IV NR (n=8) | |
|---|---|---|
| Symptoms during infusion | All six reported moderate to severe cramping, nausea, diarrhea or vomiting, faster heart rate, throat pain, congestion or chest pressure | Five of eight had minor tingling or cramping |
| Did symptoms persist? | Resolved when the infusion ended | Mild, resolved |
| Average infusion time | About 97 minutes (clients slowed the drip) | About 37 minutes |
| Liver enzymes, inflammation markers at 30 days | No clinically significant changes | No clinically significant changes |
Six people is not a trial, and there was no placebo. But the pattern matches what IV clinics widely describe: the symptoms track the speed of delivery, and slowing down is the standard fix.
Why it feels that way
The mechanism is not fully pinned down. One proposed explanation is that NAD+ and its breakdown products act on adenosine-related signalling, which affects the gut, blood vessels and heart rate; another is simply the rapid load of a molecule the body normally makes and recycles inside cells. A 2019 pilot study of a 6-hour NAD+ infusion found that infused NAD+ is cleared from plasma quickly and broken down into metabolites such as nicotinamide and methylnicotinamide, which are then excreted in urine.
What nobody has measured yet
- Repeated subcutaneous injections. Widely discussed, almost no published human data. Injection-site stinging and redness are commonly reported.
- Long-term effects. No controlled study has followed people receiving NAD+ injections for months.
- Cancer biology. NAD+ supports cell energy and repair in all cells, including tumour cells. This is a theoretical question raised by researchers, not a demonstrated risk.
- Methylation load. Breaking down nicotinamide consumes methyl groups. Whether this matters at injection doses is unknown.
NAD+ vs NMN vs NR
| NAD+ (injected) | NMN / NR (oral precursors) | |
|---|---|---|
| Human safety data | Small studies, mostly IV | Several randomized trials over weeks to months |
| Common complaints | Infusion discomfort, cramping, chest pressure | Generally mild GI symptoms |
| Status in Canada | Injectable NAD+ named in Health Canada’s April 2026 advisory | Depends on the product and its licensing |
Bottom line: the short-term effects of injected NAD+ are real, uncomfortable and mostly rate-dependent; the long-term effects are unknown. If you are considering NAD+ for your own health, a doctor can discuss the better-studied oral options.
See TrueLabs NAD+ and its COA →
Frequently asked questions
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What are the side effects of NAD+ injections?
During IV infusion, people commonly report nausea, abdominal cramping, chest pressure, faster heart rate and flushing, which usually fade when the infusion is slowed or stopped. Injection-site stinging is reported with subcutaneous use. Long-term effects have not been studied.
Why does an NAD+ IV make you feel sick?
The symptoms appear to depend on how fast NAD+ is delivered. In a 2026 clinic study, clients slowed their drips to an average of about 97 minutes because of discomfort.
Is NAD+ safe?
Short-term IV use showed no clinically significant changes in liver enzymes or inflammation markers in a small study, but controlled long-term data on NAD+ injections does not exist.
Is NAD+ or NR easier to tolerate by IV?
In a small 2026 comparison, IV nicotinamide riboside caused milder symptoms and infusions were about 60% faster than IV NAD+.
Is injectable NAD+ legal in Canada?
Injectable NAD+ sold online is named in Health Canada’s April 2026 advisory on unauthorized injectable peptides and related products.
Related reading
- MOTS-c side effects
- Epitalon side effects
- NAD+ in Canada: research guide, NAD+ vs NMN vs NR
- MOTS-C, SS-31 and NAD+: the mitochondrial toolkit
- Peptide reconstitution calculator
References
- Reyna K, Heinzen G, Patel N, et al. Intravenous infusion of NAD+ versus nicotinamide riboside: a retrospective tolerability pilot study in a real-world setting. Front Aging. 2026. DOI
- Grant R, Berg J, Mestayer R, et al. A pilot study investigating changes in the human plasma and urine NAD+ metabolome during a 6 hour intravenous infusion of NAD+. Front Aging Neurosci. 2019;11:257. DOI
- Health Canada. Think twice before injecting peptides bought online. Public advisory, April 9, 2026. Health Canada
All TrueLabs products are sold for in vitro and laboratory research use only. They are not intended for human or veterinary use, and nothing in this article is medical advice.