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InjectionFrom $166/mo
Medically reviewed by Vanessa Niles, R.N., M.D., F.A.C.O.G. —
The short answer
No safe daily limit for NAD+ injections has been established, and not every plan is daily. Your provider sets how much and how often. In one small study, daily IV NAD+ at 500 mg caused significant side effects in everyone who received it.
- There's no established daily maximum for injected NAD+.
- Many plans aren't daily at all.
- Daily IV dosing has caused strong side effects in a small study.
- Don't add extra doses on your own.
Why there's no daily limit
Safe limits come from dose-finding studies, and those haven't been done for injected NAD+. NIH does set a 35 mg adult upper limit for niacin from supplements, but that's for vitamin B3, not NAD+, and it's based on flushing.
What daily dosing studies show
A 2026 review of 500 mg IV NAD+ given daily for four days found moderate to severe cramping, nausea, vomiting, raised heart rate and chest pressure in all six people receiving it. Oral NR and NMN have been given daily in trials, but those are different molecules taken by mouth.
Per day
Your plan, not a daily maximum
Dose and frequency are set together. Without dose-finding studies, adjustments are guided by how you respond.
Signs a dose is too much for you
- Flushing, nausea or chest tightness that doesn't settle
- Headaches or fatigue after every dose
- Any symptom that worries you; tell your provider
NAD+ terms used in this guide
Questions
Questions people also ask
Is 100 mg a day safe?
No daily amount has been proven safe or unsafe for injected NAD+. Follow your prescription.
Does the niacin upper limit apply to NAD+?
No. The 35 mg upper limit is for supplemental niacin (vitamin B3), not NAD+ injections.
Can I split my dose into two shots?
Only if your provider tells you to.
Is it safe to inject every day?
Only if your provider prescribes it. No safe daily limit has been established for injected NAD+.
Can I use the spray and the injection on the same day?
Only if your provider prescribes both. Don't combine forms on your own.
Does a higher daily dose work better?
There's no evidence that it does, and higher or faster doses are linked to more side effects.
Keep reading
Related NAD+ guides
- How Much NAD+ Should I Inject? Dosage Made Simple for YouHow much NAD+ should you inject? There's no FDA-approved dose, so your provider sets it. Learn what shapes that dose, what studies used and how to measure it.NAD+ injections
- NAD+ Injection Dosage Calculator: Find Your Perfect Dose NowTurn your prescribed NAD+ dose into milliliters and U-100 syringe units in seconds, and see how many doses are in your vial. Always follow your label.NAD+ injections
- How Often Should You Get NAD Injections? A Quick Time GuideHow often should you get NAD+ injections? Learn why schedules vary, what shapes how often your provider has you inject and why more often isn't always better.NAD+ injections
Official sources
Sources and official resources
Official government and research sources behind this page, so you can check the facts yourself.
- Frontiers in AgingReyna et al. Intravenous infusion of NAD+ versus nicotinamide riboside: a retrospective tolerability pilot study (2026)
Small real-world review of side effects during NAD+ IV infusions.
- NIH Office of Dietary SupplementsNiacin: Health Professional Fact Sheet
Explains how the body turns niacin (vitamin B3) into NAD, a coenzyme used by more than 400 enzymes.
- Frontiers in Aging NeuroscienceGrant et al. Changes in the human NAD+ metabolome during a 6-hour NAD+ infusion (2019)
Small pilot study of intravenous NAD+ in healthy adults.
- U.S. Food and Drug AdministrationFDA alerts about dosing errors with compounded injectable products (2024)
Mix-ups between milliliters, milligrams and syringe units led to overdoses.
- NIH PubMedNAD+ therapy in age-related degenerative disorders: a benefit/risk analysis (2020)
Weighs early promise against the lack of long-term human trials.
Medically reviewed by Dr. Vanessa Niles, R.N., M.D., F.A.C.O.G., on October 12, 2026. This article is general education, not medical advice. NAD+ has no FDA-approved use, and compounded NAD+ is not FDA-approved or evaluated by the FDA for safety or effectiveness. Only your provider can set your dose.
Talk it through with a provider
Book a free online consultation. If NAD+ fits, a licensed U.S. provider prescribes the nasal spray or injection, with plans from $166 a month.
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