Is Botox safe? What the evidence says

Whether Botox is bad for you starts with what the FDA label actually covers.

Botox Cosmetic (onabotulinumtoxinA) is FDA-approved in adults for temporary improvement in the appearance of moderate to severe frown lines, crow's feet, forehead lines and platysma bands (vertical neck bands).

The label's cosmetic doses are specific: 20 units for frown lines, 24 units for crow's feet, and 40 units for forehead lines when they are treated together with frown lines.

If you are new to the treatment itself, our Botox guide covers how it works and what it treats.

The effect is designed to stay local.

The label states that at recommended doses, currently available analytical technology cannot detect the drug in the peripheral blood after intramuscular injection.

The most common reactions in the label's trials were eyelid ptosis (a drooping eyelid) in 3% of people treated for frown lines, against 0% on placebo; eyelid swelling in 1% of crow's-feet subjects; and, for forehead lines, headache in 9% (5% on placebo) and brow ptosis in 2%.

The label says adverse reactions generally occur within the first week after injection and, while often transient, may last several months or longer.

The injection itself can cause localized pain, swelling, redness, tenderness and bruising, and needle anxiety can cause fainting.

So there is no side-effect-free version of this treatment, and a practice that promises one is not describing the label.

Two more label boundaries matter.

The safety and effectiveness of dosing more often than every 3 months have not been clinically evaluated.

And the label says frequent or higher doses may increase antibody formation: in the crow's-feet trials, 1.5% of 916 treated subjects developed binding antibodies and none developed neutralizing antibodies, so the label advises the lowest effective dose at the longest feasible interval.

For balance, the same label states that there have been no definitive serious adverse event reports of distant spread of toxin effect with dermatologic use at the labeled cosmetic doses, the 20-, 24- and 40-unit regimens above, or at 100 units for underarm sweating.

That statement covers those labeled doses only.

It does not cover higher doses, or areas that are not on the label.

Botulism is the fair fear, since Botox is made from a botulinum toxin.

CDC researchers have addressed the question directly: they consider botulinum toxin products safe for cosmetic use when administered in clinical settings.

The label, as covered above, records no definitive serious adverse event reports of distant spread at the labeled cosmetic doses.

The serious botulism-like illnesses CDC documented between November 2023 and April 2024 followed injections with counterfeit or unverified products, or injections by people not following state requirements — and the boxed warning about spread applies to every botulinum toxin product either way.

Cancer is a different question with a narrower answer.

Long-term animal studies of Botox Cosmetic's carcinogenic potential have not been performed, per the FDA label.

In a battery of genetic toxicology tests, the drug was negative.

That is the honest state of the testing record: the genetic tests were negative, and the long-term studies have not been done.

The label names two contraindications, situations in which Botox Cosmetic is not to be used.

One is known hypersensitivity to any botulinum toxin product or to any ingredient in the formulation.

The other is an infection at the planned injection site.

Contraindications are product-specific, so they change with the brand in the vial. Dysport's label adds cow's milk protein allergy: it is contraindicated in people allergic to cow's milk protein, which the product may contain in trace amounts, alongside the same hypersensitivity and injection-site infection rules.

Other conditions are warnings rather than contraindications.

The label warns that people with neuromuscular disorders, naming myasthenia gravis, Lambert-Eaton syndrome and ALS, may be at increased risk of clinically significant effects, and advises caution in people with pre-existing cardiovascular disease or swallowing or breathing problems.

Those are reasons for a careful conversation with a provider, not an automatic no written by the label.

Pregnancy and breastfeeding sit in their own category.

There are no adequate human data on Botox Cosmetic in pregnancy and no data on whether it passes into breast milk.

Animal studies showed fetal effects at doses associated with maternal toxicity.

Pregnancy is not on the label's contraindication list, but safety in pregnancy and while breastfeeding has not been established, because adequate human data do not exist.

The serious outbreak FDA and CDC documented in 2023 and 2024 involved counterfeit or unverified product, or injections by people not following state requirements.

On April 16, 2024, FDA warned that unsafe counterfeit Botox had been found in multiple states and administered to consumers for cosmetic purposes, with adverse events including hospitalizations.

FDA said the incidents occurred when product was injected by licensed and unlicensed individuals and in non-medical or unlicensed settings, with product apparently bought from unlicensed sources.

The counterfeit vials FDA identified carried lot number C3709C3 and claimed to contain 150 units, a vial size FDA and CDC note the company does not make.

CDC's investigation of the outbreak counted 17 people in 9 states with harmful reactions after injections with counterfeit or unverified botulinum toxin products, or from people not following state requirements, between November 2023 and April 2024.

Thirteen of the 17 (76%) were hospitalized, and 6 received botulism antitoxin.

A July 2024 CDC MMWR report described the pattern in detail: seven women in Tennessee and New York City became ill after presumed counterfeit injections in nonmedical settings in March 2024, four were hospitalized, and all had ptosis, dry mouth, difficulty swallowing, shortness of breath and weakness.

"Diluted Botox" is a separate concern, and the label defines the standard.

Botox Cosmetic comes in single-dose 50-unit and 100-unit vials; the label calls for reconstitution with preservative-free saline to a concentration of 4 units per 0.1 mL, refrigerated storage after mixing, use within 24 hours, and discarding any remainder.

We found no verified data on how often dilution or storage mistakes happen in clinics, so this page won't quote a figure there.

What FDA and CDC documented in the 2024 outbreak was counterfeit and unverified product.

The label also gives you a check you can run yourself.

Genuine Botox Cosmetic shows U.S. License number 1889 on the vial and carton, and the label instructs that it not be used, and that AbbVie be contacted, if that number is missing or the tamper-evident features look broken.

The CDC's prevention advice is the plainest summary of what safe requires: get botulinum toxin injections only from a licensed, trained provider using product from an authorized source.

Even then, the CDC calls the procedure "not risk-free" when the product is FDA-approved and injected correctly.

Who may legally inject is set by state law.

AmSpa, the American Med Spa Association, describes injecting botulinum toxin as the practice of medicine, because a prescription drug is being used to affect living tissue, so it must be done by a physician, an independent-practice NP or another licensed professional acting within their scope, under rules that vary by state.

The label sets a competence bar of its own: those administering Botox Cosmetic must understand the relevant neuromuscular and structural anatomy of the treated area.

Its technique rules show why.

To reduce the risk of eyelid ptosis, the label instructs injectors to avoid the area near the levator palpebrae superioris muscle, to place lateral corrugator injections at least 1 cm above the bony supraorbital ridge, and not to inject closer than 1 cm above the central eyebrow.

Federal law requires providers who dispense or administer prescription drugs to buy them only from authorized sources, so asking where a practice orders its product is a fair question.

FDA's consumer advice during the 2024 counterfeit warning was exactly that: confirm you are receiving product from an authorized source, and ask whether the person injecting is licensed and trained to administer it.

For the fuller checklist, from medical direction to the consultation, see our guide to choosing a safe med spa.