Two reactions, two different causes
The sting and the flush get lumped together, but they aren't the same thing. The sting is local, at the spot where the needle went in. The flush is a whole-body reaction, a warm, pink, sometimes pounding feeling that comes on during or soon after the injection.
The sting traces to acidity. Dissolved NAD+ is acidic, and vendor pages and user reports put the burn down to that, not to a mixing error. We cover it in what buffered NAD+ is, and the short version is that adding a buffering agent like sodium bicarbonate raises the pH and takes the edge off. Of the 46 vendors we track for NAD+, 7 list a buffered version right in the listing name.
The flush is different. Flushing, chest tightness and a racing or pounding heartbeat are the reactions clinics and users describe, mostly when the injection or drip goes in fast. Controlled research is thin. In one small pilot study, a slow six-hour drip of 750 mg caused no reported side effects, which fits the speed explanation without proving it. Most of what we know comes from clinic experience.
What people do about each
| Reaction | Likely cause | What's commonly described |
|---|---|---|
| Sting or burn | Acidic solution | Choose buffered NAD+ |
| Flushing | Linked to injection speed | Inject more slowly |
| Chest tightness | Linked to injection speed | Slow the injection; stop if it continues or worries you |
Technique matters on top of that. A buffered vial injected quickly can still flush you, and a slow injection of an unbuffered one can still burn.
What it changes for your next step
If the sting is what's putting you off, look for "buffered" right in the listing name and read the certificate of analysis the same way you would for any vial. The how to read a COA guide covers what it should show.
If it's the flush, the NAD+ dosage page lists flushing, chest tightness and a racing heartbeat among the signs to stop or reconsider a form, and slowing the rate as the most common first adjustment. A reaction that frightens you is reason enough to stop, and some people switch to an oral form such as NMN, a capsule your body turns into NAD+, which is where the difference between NAD+ and NMN comes in.
Still deciding whether to start? See whether NAD+ is worth it. For amounts, how much NAD+ per injection has the described range. The NAD+ page has the rest.
It's sold for research, and the big human trials haven't been run yet. You knew that, it's why you're reading this and not the label.
Questions people ask
Why does NAD+ burn when injected?
NAD+ mixed with water is acidic, and that acidity is most of why it stings at the injection site. Vendor pages and user reports point to the solution itself, not a mixing mistake.
Why does NAD+ make me flush?
Flushing, a racing heartbeat and chest tightness are most often reported at faster injection or infusion speeds. Why the speed matters isn't well established.
Does buffered NAD+ stop the flushing too?
Buffering is aimed at the sting, so don't count on it to prevent flushing. Slowing the injection is the more commonly described fix for that.
How do you make NAD+ injections hurt less?
Buffered NAD+ and a slower injection are the two things people describe most. Technique still matters, and a completely pain-free injection isn't guaranteed.
When should you stop NAD+ injections?
Flushing, chest tightness or a racing heartbeat are the signs people take as a reason to slow down or pause. A reaction that frightens you is reason enough to stop.
