NAD Injection Side Effects: What Is Reported

The NAD injection side effects people actually report are gastrointestinal and cardiovascular, they arrive during administration, and they stop within minutes of it ending. In the only published tolerability comparison of intravenous NAD+, every one of six clients reported moderate to severe abdominal cramping, diarrhea, nausea, vomiting, a faster heart rate, throat pain, congestion and chest pressure — and all of it ceased immediately when the infusion finished. A separate slow-infusion pilot recorded no adverse events, but because the studies differed in design and did not randomize infusion rate, they do not establish speed as the cause.

What NAD injection side effects look like in the published data

The one direct comparison is a 2026 retrospective review of records from a commercial wellness clinic (Reyna et al., Frontiers in Aging 2026). Six clients received 500 mg of NAD+ intravenously in 500 mL of saline on four consecutive days; eight received nicotinamide riboside the same way. Clients set their own infusion rate by tolerance.

Every symptom in the NAD+ group ceased immediately on completion, and blood work over 30 days showed no significant change in ALT, AST, hsCRP, BUN and creatinine, or TSH.

Read it as a signal, not a settled profile: fourteen people, one clinic, no blinding, no randomization — and still the best direct evidence there is, which tells you how thin this literature remains.

What the infusion studies can and cannot show

Set the pilot against the one human pharmacokinetic study of infused NAD+ (Grant et al., Frontiers in Aging Neuroscience 2019). Eight of eleven healthy men aged 30 to 55 received 750 mg in saline over six hours — roughly 2 mg a minute — and three received saline. The authors report no adverse events during the infusion in either group, and markers of hepatic stress that fell slightly rather than rising.

Because the studies differed in design and did not randomize infusion rate, this cross-study contrast does not establish speed as the cause of the symptoms.

The mechanism is plausible. NAD+ sits in extracellular fluid at very low concentrations, and the immune system treats it there as a danger signal released by damaged cells, with proinflammatory effects when levels are pushed far above normal. The 2019 study also found infused NAD+ vanished from plasma entirely for two hours, cleared and metabolized faster than it accumulated, with the metabolite methylnicotinamide up around 350% by six hours. That study did not compare infusion rates, so it cannot show that a faster drip outruns clearance or establish slowing the line as the answer to symptoms.

What oral precursor trials can and cannot tell you

Much of what circulates about NAD side effects is borrowed from oral precursor studies — far larger, far less eventful. In an eight-week randomized trial of 140 overweight but otherwise healthy adults, nicotinamide riboside at 100, 300 and 1,000 mg a day raised whole-blood NAD+ by 22%, 51% and 142% with no reports of flushing and no significant difference in adverse events against placebo (Conze et al., Scientific Reports 2019). A crossover trial in 30 middle-aged and older adults taking 1,000 mg daily for six weeks logged 14 mild adverse events across seven participants — nausea, flushing, leg cramps, bruising — with flushing also reported on placebo (Martens et al., Nature Communications 2018).

Two things follow. Oral tolerability does not transfer to a needle: route, peak concentration and speed of exposure all differ. And the flushing people describe during an infusion is not the familiar niacin flush — nicotinic acid causes that above roughly 50 mg a day, nicotinamide does not, and nicotinamide is what NAD+ breaks down to. What NAD+ does inside the cell is covered in our guide to NAD+ injections.

Injection-site reactions and subcutaneous NAD

Almost all of the above is about drips. What Promise dispenses is a subcutaneous injection — NAD+ as a buffered 100 mg per mL vial — a different exposure: a small volume under the skin, not half a liter into a vein over an hour.

Local reactions are the expected complaint there: stinging, redness, or a small firm area that settles. NAD+ in solution is acidic, which is why a compounding pharmacy pH-adjusts it, and why sting is a formulation question as much as a technique one. The harder point: no human trial of subcutaneous NAD+ has been published at all, so its profile comes from pharmacology, the intravenous data and clinical experience — and anyone publishing a definitive table for it is presenting missing data as a finding.

NAD+ is not the only thing in Promise's energy and focus category acting on mitochondrial metabolism. MOTS-c is a peptide encoded in mitochondrial DNA, dispensed as a 2 mg per mL subcutaneous vial, so its volumes and tolerability questions are different ones.

The risk that has nothing to do with the molecule

On 30 October 2024 the FDA reminded compounders to use only ingredients suitable for sterile compounding, saying it was aware of compounders using food-grade NAD+ sold by repackagers to make intravenous products. Food-grade material, the agency wrote, is not suitable for compounding sterile drugs without appropriate processing, because of the high risk of contamination with microbes and endotoxins. In the same notice the FDA said it had received adverse event reports following NAD+ injectable drugs — severe chills, shaking, vomiting and fatigue, some requiring medical treatment — consistent with excessive levels of endotoxins.

That is a completely different failure mode from the transient infusion-associated symptoms in the retrospective series: rigors and fever hours after a dose are a question about what was in the vial, not about NAD+. It is the strongest practical argument for knowing which licensed pharmacy prepared your medication — how compounded medications are made sets that out.

There is no approved NAD+ injectable product in the United States. Through Promise, NAD+ is dispensed as a compounded medication, which is different from an FDA-approved product: the formulation offered here is not FDA-approved, and compounded medications are not reviewed by the FDA for safety, effectiveness or quality. A licensed provider may still prescribe a compounded formulation where they judge it appropriate — that decision is between you and your doctor.

Who a prescriber screens before prescribing NAD

Because the reported effects are cardiovascular and gastrointestinal and arrive during administration, screening is about who would tolerate that badly, and who has reason to avoid raising NAD+ availability at all. A provider typically weighs:

• Cardiac history. A raised heart rate and chest pressure are the reported pattern; in someone with angina or an arrhythmia those become symptoms much harder to interpret.
• Active or recent cancer. NAD+ metabolism is an active target in cancer biology, and availability of the coenzyme supports the same repair and energy machinery in dividing cells generally (Chiarugi et al., Nature Reviews Cancer 2012).
• Liver and kidney function, since the metabolites are cleared hepatically and renally, and the reassuring liver data comes from eleven healthy men over eight hours.
• Pregnancy or breastfeeding, where there is no data at all.
• Current medications, and the state you live in, since the prescriber has to be licensed where you are.

The dose and the schedule are the prescriber's to set, not a chart's — and because the reported pattern resolves on stopping, telling them about symptoms beats pushing through.

A licensed provider in Promise's prescriber network reviews every request and prescribes NAD+ only when it is appropriate for you. Not everyone qualifies.