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The short answer
Some people react badly to a shot of NAD+ under the skin. They flush hard, get a pounding headache, or feel queasy for hours. Deciding to stop is a fair choice. What you shouldn’t do is guess at the cause and change how you use it on your own. A reaction needs a proper look from your clinician.
Zappy’s NAD+ injection is compounded and not FDA-approved.
Why people want it in the first place
People add NAD+ on a GLP-1 because the weight is coming off fast and they feel flat.
Weight can leave quickly on these medicines, and not all of it is fat. Fast weight loss takes some lean mass (muscle and other non-fat tissue) with it. The long-term effects on strength and function aren’t well understood yet.
Here’s the part that works against our own product. Nobody has shown that this lean-mass loss is what makes you feel run down, which is the feeling NAD+ is sold to fix. There’s also no trial-grade evidence that NAD+ improves how energetic people feel. So set your expectations before you buy vials.
What can cause a reaction
The reaction can include flushing, head pressure, nausea, and a racing feeling. It can also come from the product itself, a contaminated batch, how the shot was given, or something else going on in your body. That’s why it needs a real look.
Some people compare it to a niacin flush, where blood vessels briefly widen and you feel warmth and pressure in your face and chest. But nobody has pinned down the exact pathway for subcutaneous NAD+, so treat that as a best guess rather than settled fact. Don’t change how you inject on your own. Tell your clinician what happened.
Who sets the dose
There’s no one NAD+ schedule that fits everyone. There’s no published dose-finding study for subcutaneous NAD+ to point you to. Your dose, how often you take it, and how it’s given are set for your exact product. Your clinician and the pharmacy that makes it decide those. Follow the instructions that come with your prescription.
If you react
- Stop the injection.
- If you have trouble breathing, swelling of your face or throat, fainting, or chest pain, get emergency care.
- If you get a fever, chills, shaking, a fast heartbeat, or feel very unwell within hours of a shot, get urgent care the same day. The FDA has reported reactions like these after NAD+ injections, some linked to contamination.
- Spreading redness, warmth, or pus where you injected needs a same-day call. It can be an infection.
- Otherwise, call your clinician before your next dose. They’ll look at the product, how it was given, and other causes.
- Don’t change your dose or how you inject on your own. Keep the vial so the pharmacy can check the batch.
What NAD+ can’t do
A common mistake is expecting NAD+ to fix how you feel on a GLP-1. What has real evidence is protecting your lean mass while you lose weight, through resistance training plus protein. Clinicians commonly aim for roughly 1.2–1.6 g of protein per kg of body weight each day, and that’s where your effort belongs. Whether NAD+ adds anything is unproven, and it can’t replace training and protein.
What we don’t know is whether topping up NAD+ does anything measurable for the fatigue people report on a GLP-1. No trial has tested subcutaneous NAD+ against placebo in people actively losing weight on a GLP-1. Until one does, keep your protein up. Don’t expect NAD+ to do the work the barbell is supposed to do. Either way, a clinician reviews your case and can look into any reaction you have.
