Key takeaways
- Safety: Botox is FDA-approved and safe for treating migraine, overactive bladder, and more. Side effects of Botox can range from mild to serious, and typically appear in the first week.
- Duration: Many localized reactions, such as drooping eyelids or swelling, are temporary and may resolve on their own. But it’s possible for some side effects of Botox to last for several months.
- Long-term risks: It’s generally safe to receive Botox injections long term. But it’s important to know the signs of “Botox resistance,” which can make Botox less effective over several years.
This article provides an overview of Botox safety based on the latest prescribing information (PI) and clinical study data.
By understanding both the possible side effects and long-term safety guidelines, you can work with a healthcare professional to ensure the most effective treatment plan.
Boxed warningBotox is approved by the Food and Drug Administration (FDA) for many cosmetic and medical uses. However, it also carries an FDA boxed warning about the potential for the distant spread of toxin effect.
While rare, this can lead to serious symptoms, like difficulty breathing or swallowing. Explore this warning in detail in the “Serious risks: Understanding the FDA boxed warning” section.
In most cases, side effects of Botox usually appear within the first week after the injection. These reactions are generally temporary, but it’s important to know that in some cases, they can last for several months or longer.
This section does not discuss every common side effect reported with Botox. For a complete list of side effects, take a look at the prescribing information for Botox and Botox Cosmetic.
Injection site reactions
Because Botox is administered via a needle, it is very common to experience a reaction where the injection was given. You might notice localized:
- pain
- tenderness
- swelling
- redness (erythema)
- bleeding or bruising
If you experience needle-related anxiety, receiving Botox injections can also trigger something called a vasovagal response. This means you might start to feel lightheaded, dizzy, or even briefly faint during or right after the procedure.
If you tend to feel faint around needles, please be sure to let your injector know ahead of time.
Botox headaches: Causes and duration
Although Botox is used to treat headaches caused by chronic migraine, it can also cause headaches as a side effect.
According to clinical trials of Botox and Botox Cosmetic, headaches were reported by 9% of people treating forehead lines, 11% of people treating cervical dystonia (neck muscle spasms), and 5% of people treating chronic migraine.
If a headache occurs, it is usually mild and can typically be managed with over-the-counter pain relievers. But it’s important to check with your pharmacist or doctor about which medications are safe to take with Botox.
Experiencing side effects? After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. If you develop a side effect while taking this drug and want to tell the FDA about it, visit MedWatch or call 800-FDA-1088.
The potential side effects of Botox can vary significantly based on the condition it’s being used to treat. This is because Botox is injected in various parts of the body and at different dosages, depending on the condition being treated.
Here is a breakdown of the most commonly reported side effects based on the specific condition being treated.
Side effects of Botox for cosmetic uses:
| Condition treated | Most common side effects |
|---|---|
| lines between the eyebrows (glabellar lines) | • eyelid drooping (ptosis) |
| forehead lines | • headache • eyebrow drooping (brow ptosis) |
| crow’s feet (lateral canthal lines) | • eyelid swelling (edema) |
Side effects of Botox for medical uses:
| Condition treated | Most common side effects |
|---|---|
| migraine | • neck pain • headache • eyelid drooping • muscle aches and pains • muscle stiffness or weakness • pain at the injection site |
| excessive sweating | • pain or bleeding at the injection site • sweating in other parts of the body |
| limb spasticity | • pain in the hands or feet (in adults only) • upper respiratory infections, such as the common cold (in children only) |
| head and neck pain (cervical dystonia) | • difficulty swallowing • upper respiratory infections, such as the common cold |
| eyelid twitching and strabismus (crossed eyes) | • eyelid drooping • dry eyes |
| bladder problems | • urinary tract infections (UTIs) • urinary retention (in adults only) |
The tables above do not include every common side effect reported with Botox. For a complete list of side effects, check out the prescribing information for Botox and Botox Cosmetic.
While most side effects are localized and manageable, Botox also has a boxed warning. This is the most serious type of safety warning issued by the FDA. The boxed warning alerts both you and your doctor to a rare but very serious risk: the distant spread of the toxin.
Distant spread of toxin: Symptoms to know
Sometimes, botulinum toxin can spread from the injection site to other parts of the body. This can produce symptoms of a serious, life threatening condition called botulism.
These symptoms can happen hours, days, or even weeks after you receive your injection. It’s important to seek immediate medical help if you experience any of the following symptoms:
- trouble swallowing, speaking, or breathing
- loss of strength or widespread muscle weakness all over the body
- severe or long-lasting headache
- double vision, blurred vision, or severely drooping eyelids
- hoarseness or a total change or loss of your voice
- loss of bladder control (incontinence)
The risk of these symptoms is generally highest in children receiving Botox for muscle spasticity, but it can happen in adults as well. Certain preexisting conditions, such as those that affect your breathing or swallowing, can further increase the risk of serious symptoms.
Because Botox works by temporarily paralyzing muscles, you may wonder whether long-term use will permanently affect your face or body.
Botox blocks the nerve signals that tell your muscles to contract. When a muscle isn’t used, it can atrophy over time (meaning it shrinks or weakens).
However, the body is highly adaptable. Over time, your nerves find new paths to the muscle, slowly reversing the block, and the muscle starts working normally again.
Studies of Botox show that it generally remains safe even with repeated, long-term use. In these studies, the safety of Botox did not change over time.
Understanding Botox resistance and antibodies
Although your muscles generally recover, there is a different long-term risk to be aware of: immunogenicity, also known as “Botox resistance.”
Because Botox contains a foreign protein, your immune system might sometimes mistake it for a threat. When this happens, your body can create “neutralizing antibodies” to block it. If these antibodies develop, they can prevent the medication from doing its job. This means your Botox treatments might become much less effective over time, or stop working entirely.
It’s not fully understood which factors cause Botox resistance. But clinical studies suggest that receiving Botox injections too frequently, or at very high doses, can increase the risk of developing neutralizing antibodies.
Other serious side effects that have been reported with Botox include:
- corneal ulceration (open sore on the surface of the eye) in adults and children using Botox for eyelid twitching
- retrobulbar hemorrhage (blood collecting behind the eyeball) in adults and children using Botox for crossed eyes
- urinary retention in adults using Botox for bladder problems
- serious allergic reaction to Botox or any of its ingredients
If you develop serious side effects during Botox treatment, call your doctor right away. If the side effects seem life threatening or if you think you’re having a medical emergency, immediately call 911 or your local emergency number.
Medical PerspectiveYou should seek immediate medical care if you experience red-flag symptoms such as chest pain, shortness of breath, or significant difficulty breathing.
Additionally, experiencing the “worst headache of your life” can signal a life threatening condition and requires urgent attention, rather than a standard follow-up call to your doctor.
— Alex Nguyen, PharmD, RPh, CPh
» More on this: 18 Remedies to Manage Headaches and When to See a Doctor
Quotes represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.
There are several steps that you and your healthcare professional can take together to help ensure your Botox treatments remain as safe and effective as possible:
- Pace your treatments: To minimize the risk of developing Botox resistance, doctors generally recommend using the lowest effective dose and waiting as long as possible between your injection sessions.
- Share your full medical history: Botox is not safe for everyone. It’s important to tell your doctor if you have any neuromuscular disorders (like ALS, Lambert-Eaton syndrome, or myasthenia gravis). Botox can severely increase your risk of muscle weakness and breathing problems.
- List your medications: Certain drugs can cause serious interactions with Botox. Be sure your doctor knows if you take any antibiotics, muscle relaxants, sleep medications, anticholinergics, or blood thinners. Taking some of these alongside Botox can dangerously exaggerate muscle weakness.
- Don’t drive if you feel “off”: If you experience any loss of strength, muscle weakness, blurred vision, or dizziness after an injection, do not drive a car or operate machinery.
Many localized reactions, like bruising or swelling, improve within a few days. However, some side effects can last for several months or longer. If a side effect is bothering you or won’t go away, reach out to your doctor.
Yes, it can. In clinical studies, some people reported flu-like symptoms after receiving Botox injections. These symptoms include fever, nausea, and body aches (myalgia).
Upper respiratory tract infections and bronchitis are also reported side effects, particularly in people being treated for spasticity or cervical dystonia.
Using Botox “off-label” for unapproved uses has been linked to serious adverse reactions, including:
- excessive weakness
- severe trouble swallowing (dysphagia)
- aspiration pneumonia (a lung infection resulting from inhaling food or drink due to trouble swallowing)
In some cases, using Botox for unapproved conditions can cause life threatening reactions. The safety and effectiveness of Botox for unapproved uses have not been established.
Botox may not be right for you if you have certain medical conditions or other factors that affect your health. Talk with your doctor about your health history before you start Botox treatment. The following list includes factors to consider:
- previous allergic reaction to Botox or any of its ingredients
- active skin infection at the injection site
- active UTI
- urinary retention
- amyloid lateral sclerosis (ALS)
- Lambert-Eaton syndrome
- myasthenia gravis
- amyloid lateral sclerosis (ALS)
- Lambert-Eaton syndrome
- myasthenia gravis
- breathing or swallowing problems
- upcoming surgery
- pregnancy or breastfeeding
» More on this: Botox Interactions: Alcohol, Medications, and Others
Botox is FDA-approved and generally safe for cosmetic and medical use, but side effects are possible. Temporary side effects like injection-site reactions and headaches usually resolve on their own in a couple of weeks. However, it’s also possible for some side effects to last for months.
Long-term use is usually safe, but repeated injections at high doses may cause “Botox resistance.” To help prevent the risk of side effects, it’s important to tell your doctor about your medical history and current medication list.
Disclaimer: While Healthline strives for factual, comprehensive, and current information, this article is not a substitute for a licensed healthcare professional’s expertise. Always consult a doctor before taking or discontinuing any medication. Drug information is subject to change and may not cover all uses, directions, precautions, warnings, interactions, reactions, or adverse effects. The lack of a warning does not guarantee a drug’s safety, effectiveness, or appropriateness for all patients or specific uses. Learn more about our approach to content integrity.