Botox (onabotulinumtoxinA) is a prescription drug that’s used to relax certain muscles and glands. It comes as a powder that’s mixed into a liquid solution for injection. It may be given once every 3 months.

Botox injections may be given to adults and some children to treat these conditions:

Doctors may also prescribe Botox injections for adults with the following conditions:

The active ingredient in Botox is onabotulinumtoxinA. (An active ingredient is what makes a drug work.)

This article describes the dosages of Botox, as well as its strengths and how it’s given. To learn more about Botox, see this in-depth article.

Adult dosages are discussed first. For details on dosing in children, see the section “What’s the dosage of Botox for children?” below.

This table describes the usual doses of Botox given to adults during a single treatment session.

ConditionDose (divided across injections)Injection sites and muscles
chronic migraine155 units31 sites in 7 head and neck muscles groups
excessive underarm sweating50 units per armpit10–15 sites per armpit
muscle spasticity, lower limbs300–400 unitsup to 16 sites in 5 muscle groups
muscle spasticity, upper limbs75–400 unitsup to 18 sites in 13 muscle groups
neck muscle spasms15–100 units per muscleup to 8 muscle groups
strabismus (crossed or misaligned eyes)1.25–25 units per muscle1 or more of the 6 muscles around the eye
blepharospasm (twitching eyelid)1.25–2.5 units per eye3 sites per affected eye
urinary incontinence from a neurologic condition200 units30 sites in the bladder muscle
urinary incontinence, urgency, and frequency from overactive bladder100 units20 sites in the bladder muscle

When you start treatment, your doctor will usually begin with the lowest recommended dose. If your doctor is giving you Botox injections for more than one condition, the combined Botox dosage should be fewer than 400 units within a 3-month period.

Keep reading to learn more about Botox dosing.

What is the form of Botox?

Botox comes as a powder in single-use vials. A healthcare professional will mix the powder with sterile saline to make a liquid solution and will then draw it into a syringe. Your doctor will inject the Botox liquid solution into the appropriate muscles or, in some cases, into the skin.

What strengths does Botox come in?

Botox vials are available in two strengths: 100 units per vial and 200 units per vial.

Your doctor will determine how much sterile saline solution to add to the Botox powder so that the drug has the proper concentration. The concentration is measured in units of Botox per 0.1 milliliter of sterile saline solution (units/0.1 mL).

What are the usual dosages of Botox?

Dosages vary depending on your condition and the size, number, and location of muscles or skin areas involved. Your doctor will carefully select a starting dosage and may adjust it with later treatments as needed. They’ll ultimately prescribe the smallest dosage that provides the desired effect.

The information below describes dosages that are commonly used or recommended. But your doctor will determine the best dosage to fit your needs.

Dosage for migraine

If you have chronic migraine, your doctor may recommend Botox for injection into the muscles of your head and neck. The total dosage is usually 155 units of Botox. Your doctor will divide this dose across different areas, including:

  • the back of your head
  • either side of the spine at the top of your neck
  • along the trapezius muscle where the neck meets the shoulders
  • your forehead
  • both temples

You’ll usually receive injections every 12 weeks to prevent headaches and other migraine symptoms.

Dosage for urinary incontinence caused by an overactive bladder

Botox can help certain bladder problems. These include urge urinary incontinence as well as urgency and frequency caused by an overactive bladder.

If you’re receiving Botox to treat an overactive bladder, your doctor will use a cystoscope to see and access the inside of the bladder. Then they’ll inject a total of 100 units of Botox throughout the bladder muscle. (This procedure is done under anesthesia so that you’re comfortable.)

Your doctor will usually give you repeat Botox injections when the effect wears off, but no sooner than 12 weeks from the last injection. In studies, people were usually ready for their next treatment after approximately 19–24 weeks.

Dosage for urinary incontinence caused by a neurologic condition

If you have a neurologic condition, such as multiple sclerosis or spinal cord injury, that’s causing urinary incontinence, your doctor may recommend Botox injections to treat the urinary incontinence.

Using a cystoscope to see and access the inside of the bladder, your doctor will inject a total of 200 units of Botox throughout the bladder muscle. (This procedure is done under local anesthesia with or without sedation, or general anesthesia.)

Your doctor will repeat your injections once the effect has worn off, but no sooner than 12 weeks from the last injection. In studies, people were usually ready for their next treatment after 42–48 weeks.

Dosage for neck muscle spasms

This rare condition is called cervical dystonia. It causes your neck muscles to contract in spasms. Your head may painfully twist to one side or tilt forward, backward, or to one side.

If you have cervical dystonia, your doctor may recommend Botox injections. Depending on which muscles spasm, your doctor will carefully inject Botox into one or more muscle groups of your neck. To determine the exact injection location of the needle tip, your doctor may use electromyography or ultrasonography during the procedure.

When you receive your first treatment, your doctor will start you on a low dose of Botox to see how you respond to the medication. This may be about 100 units.

Your dose will be carefully adjusted over time to find the right amount for you. Depending on which muscles are involved, your doctor may inject 15–100 units of Botox into each individual muscle. In one study, average total doses were between 200 and 300 units. Repeat treatments were usually required every 12 weeks.

Dosage for excessive sweating

Botox is approved to treat excessive armpit sweating, but it may be used off-label for treating excessive sweating in certain other areas, such as on the hands or face. (With off-label use, doctors prescribe a drug for a purpose other than what it’s approved for.)

To treat the armpit area, your doctor will inject Botox just below the surface of the skin. The usual dosage is 50 units divided into 15­–20 small injections per armpit.

You’ll return for repeat injections once the effect of the previous treatment has worn off.

Dosage for strabismus (crossed or misaligned eyes)

Eyes may become crossed or misaligned when one or more eye muscles are overactive and interfere with coordinated eye movement. Botox can temporarily relax the overactive eye muscles, allowing the eyes to align properly.

If you’re receiving Botox injections in one or more eye muscles, your doctor will make sure you’re comfortable by first giving you topical anesthetic eye drops. Then, with the help of electromyography to identify the small muscles around the eye, your doctor will inject 1.25–5 units of Botox into the appropriate eye muscle or eye muscles.

You should notice a difference in your eye movement 1–2 days after the injection, and this change will likely become more obvious over the first week. Then, 7–14 days after the initial injection, your doctor will re-examine your eyes to see the effect of the Botox. This helps your doctor select the dose for the next injection.

The effect should last 2–6 weeks, and then gradually wear off over the same time period. Repeat injections may be performed once the initial effect has worn off.

Dosage for blepharospasm (twitching eyelid)

Blepharospasm occurs when your eyelid muscles cause your eyelids to twitch or close involuntarily. Botox may be prescribed to decrease eyelid muscle overactivity.

To treat blepharospasm, your doctor will inject a total of 1.25–2.5 units of Botox around the affected eye. The dose is divided across three injections: two injections in the upper eyelid and one injection in the lower eyelid.

Depending on how you respond to this treatment, your doctor may increase your dose for future injections. Repeat injections may be scheduled every 12 weeks or more.

Dosage for muscle spasticity

If you’re prescribed Botox to treat muscle spasticity, your initial dosage will depend on the area to be treated and how many muscles are in spasm. Dosages for repeated treatments may be different, depending on which muscles are in spasm at the time and how you responded to your last treatment.

For muscle spasticity affecting the upper limbs, your doctor will usually inject 75–400 units of Botox in divided doses to the affected muscles.

For muscle spasticity affecting the lower limbs, the Botox dosage is likely to range between 300 and 400 units. The dosage is divided among the muscles in spasm.

Your doctor may use electromyography to help determine where to inject the drug. Repeat injections are performed once the initial effect has worn off and after 12 weeks have passed since the last treatment.

What’s the dosage of Botox for children?

When starting treatment in children the lowest recommended dosage should be used. If your child is being treated for more than one indication with Botox, the total dosage should not be greater than 10 units of Botox per kilogram (kg)* of body weight (units/kg) or 340 units total (whichever is less) over a 3-month period.

* One kg equals about 2.2 pounds (lb).

Dosage for strabismus (crossed or misaligned eyes) in children

For children ages 12 years and older, doctors may recommend Botox for treatment of strabismus (crossed or misaligned eyes). The dosage is the same as for adults. For some children, the procedure may be done under general anesthesia.

Dosage for muscle spasticity in children

Botox may be used to treat muscle spasticity in children ages 2 years and older. The dosage is based on the child’s weight and the location of the injections. Your child’s doctor may use ultrasonography or electromyography to help identify the muscles and the best place for the injections.

For treatment of upper limb spasticity, a dose of 3–6 units/kg is recommended, up to a maximum dose of 200 units. This dosage is divided among the upper limb muscles in spasm.

For treatment of lower limb spasticity, the total Botox dose should be 4–8 units/kg, divided among the affected muscles. The total dose given shouldn’t exceed 8 units/kg or 300 units, whichever is lower. This dosage is divided among the lower limb muscles in spasm.

Dosage for blepharospasm (twitching eyelid) in children

If your child has blepharospasm (a twitching eyelid) and is at least 12 years old, their doctor may recommend Botox treatments. The dosage is the same as for adults.

Dosage for urinary incontinence due to a neurologic condition in children

Your child’s doctor may recommend Botox injections for the treatment of urinary incontinence due to a neurologic condition. Botox is approved for this condition in children who are age 5 years old and older.

The dosage is based on your child’s body weight. If your child weighs more than 34 kg (approximately 75 lb), the dosing is the same as for adults: 200 units.

For children who weigh less than 34 kg, the recommended dose is 6 units/kg.

The procedure may be performed under general anesthesia or other form of anesthesia. Repeat injections are necessary once the effect wears off. In studies, injections were repeated every 30 weeks on average. Repeat injections shouldn’t be given sooner than 12 weeks from the last treatment.

Is Botox used long term?

Yes, Botox is usually used as a long-term treatment. If you and your doctor determine that it’s safe and effective for your condition, you’ll likely continue to receive injections over the long term.

The dosage of Botox you’re prescribed may depend on several factors. These include:

  • the type and severity of the condition you’re using the drug to treat
  • your age
  • body weight (for children)
  • other medications you may be taking

Your prescribing doctor will give you your Botox injections. How Botox is given depends on the condition it’s treating. Some considerations include:

  • Location. You may receive your injections at your doctor’s office, at a surgical center, or at a hospital.
  • Anesthesia. Your doctor may give you a local anesthetic to numb the area. This may be given with or without sedation. In some cases, your doctor may recommend that an anesthesiologist provide a general anesthetic for you.
  • Additional equipment your doctor may use. Your doctor may use electromyography or ultrasonography to help locate the muscles and best sites for injection. To reach and see the inside of the bladder, your doctor may use a cystoscope.
  • Type of injection. Most often, Botox is injected into a muscle. But to treat excessive sweating, Botox is injected into the skin.
  • Number of injection sites. Usually, several small injections are made in multiple areas rather than a single injection. This is because Botox doesn’t spread far from its injection site.

To learn more about how Botox is given for your condition, talk with your doctor.

If you miss your appointment to receive your Botox injection, call your doctor’s office. They’ll reschedule your appointment and adjust your dosing schedule if needed.

If you need help remembering your Botox appointments, try using a medication reminder. This can include setting an alarm or downloading a reminder app on your phone.

The sections above describe the usual dosages as provided by the drug’s manufacturer. If your doctor recommends Botox for you, they’ll prescribe the dosage that’s right for you.

Talk with your doctor if you have questions or concerns about your current dosage.

Here are some examples of questions you may want to ask your doctor:

  • Could the recommended dosage of Botox be different for me because of my other medications?
  • Do I have a higher risk of side effects from Botox with larger doses of Botox?
  • How often should I expect to receive Botox injections?
  • Will I need anesthesia?

To learn more about Botox, see these articles:

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Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.