NAD+ therapy has a better safety profile than most prescription medications, but that doesn’t mean it’s without side effects. The experience varies significantly depending on delivery method, dose, and individual response.
Here’s what to actually expect — from both the research and my personal experience over 14 months of use.
IV Infusion Side Effects
IV NAD+ infusions produce the most pronounced side effects, primarily because the dose is delivered rapidly into the bloodstream at a high concentration.
The flush. The most commonly reported experience during NAD+ IV infusion is a flushing sensation — warmth, tingling, or pressure that can affect the face, chest, or extremities. This is caused by NAD+ activating certain cellular pathways rapidly and is temporary, typically lasting minutes to an hour.
The flush can range from mild warmth to an intense sensation that feels uncomfortable. It’s not dangerous, but for people who aren’t expecting it, it can be alarming. Slowing the infusion rate reduces the intensity significantly — experienced clinicians adjust the drip rate based on patient tolerance.
Nausea and cramping. Some people experience nausea, stomach cramping, or chest tightness during IV infusion, again related to the rapid delivery of a high-dose NAD+. These effects are more common at higher doses and faster infusion rates and typically resolve when the rate is slowed.
Headache. Mild headache during or after infusion is reported by some patients. Staying well-hydrated before a session reduces this significantly.
Subcutaneous Injection Side Effects
At-home subcutaneous injections produce substantially milder side effects than IV infusion because the dose is lower and the delivery is slower, allowing the body to absorb NAD+ more gradually.
Injection site reactions. The most common experience is minor redness, swelling, or tenderness at the injection site. This is a normal inflammatory response to subcutaneous injection and typically resolves within a day or two. Rotating injection sites reduces accumulation of these reactions.
Mild flush. Some people experience a mild version of the flush associated with IV infusion, but it’s typically much less intense with subcutaneous delivery. I noticed mild warmth at higher doses in the first few weeks that diminished as my body adapted.
Fatigue on injection days. A subset of people report feeling more tired than usual on the day of injection. The current thinking is that this reflects the body actively responding to increased NAD+ availability. It’s generally temporary and tends to improve after the first few weeks.
What I Experienced
I’ve used subcutaneous injection through a telehealth protocol for over a year. My side effect experience was limited to mild injection site reactions in the first two to three weeks and occasional mild fatigue on injection days in the first month.
Both resolved. By month two, injections were entirely routine with no notable side effects.
I did not use IV infusion, so I can’t speak to that experience personally. What I’ve read from people who have used both suggests the IV flush is real and worth knowing about before your first session.
Rare but Reported Effects
In clinical reports and patient experience data, a small number of people have reported:
- Palpitations or racing heart during IV infusion (almost always resolved by slowing the drip rate)
- Dizziness during or after IV sessions
- Anxiety or restlessness, particularly at higher IV doses
These are more commonly associated with high-dose IV protocols and are rarely reported with at-home subcutaneous injection at typical therapeutic doses.
Who Should Be Cautious
NAD+ therapy should be discussed with a physician if you have a history of significant cardiovascular disease, are pregnant or breastfeeding, or have active cancer. NAD+ is involved in cell proliferation pathways, and the implications for cancer contexts are still being studied.
For healthy adults in the age range where NAD+ supplementation is most discussed — 40 and older — the safety profile is considered favorable in the current literature.
How to Minimize Side Effects
For IV infusion: start at a lower dose or slower rate, hydrate well before the session, and communicate with your provider about tolerance in real time. Most side effects are directly related to infusion speed.
For subcutaneous injection: rotate sites consistently, inject slowly, and allow the medication to reach room temperature before injecting (cold medication increases discomfort). Follow your provider’s protocol for dose and frequency rather than improvising.