What is a botulinum toxin injection?

Botulinum toxin type A (Botox®) is a medication containing highly diluted toxin produced by a species of bacteria called Clostridium botulinum. In its original form, the botulinum toxin is a dangerous substance that can cause botulism - a severe, sometimes fatal, paralytic disease. However, when heavily diluted, a botulinum toxin injection has many medical uses.

Mechanism of action

Botox works by blocking the release of an important chemical, known as acetylcholine, at the connection between nerves and muscles. This prevents the muscles from contracting and allows them to remain in a relaxed state. The effects can take few days to become apparent as the muscle gradually relaxes. The effects are generally temporary as the nerve cells gradually grow new connections to the muscles. This can take 3-6 months.


Botox can be used for a variety of clinical uses. It is mainly known for its use in cosmetic treatments; however it also has a wide range of other medical applications.

Cosmetic use

Botox is used cosmetically when injected into facial muscles. It reduces the appearance of the wrinkles around the eyes ('crow's feet'), on the neck, across the bridge of the nose, on the forehead ('furrowed brows') and other facial lines and wrinkles.

Because a Botox injection relaxes the muscles, it will not affect facial features that aren't caused by tight muscles. Botox cannot correct facial wrinkles caused by other factors such as sun damage.

A Botox (BTX) injection can be used cosmetically to reduce skin wrinkles.Cosmetic use of Botox to reduce the appearance of wrinkles. 

Medical uses

Muscular conditions

Botox is used to treat numerous disorders caused by muscular problems. These disorders include (but are not limited to):

Conditions affecting glands

Botox can also have an effect on some glands of the human body. As such, it can be used to treat glandular conditions such as excessive sweating, drooling and tearing.

Other uses

Additional uses of Botox include treatment of:

  • Headaches and migraines;
  • Rhinitis;
  • Frey's syndrome (which causes facial flushing and sweating during and after eating), and;
  • Facial scars and wound healing;

Further medical uses for Botox are regularly emerging - relief of asthma and multiple sclerosis symptoms are two uses currently being trialed.


Any organ of the body that secretes substances, such as hormones or enzymes, that are used by other parts of the body.

Graves' eye disease

Part of an autoimmune thyroid disease that can cause eye inflammation, bulging, grittiness and redness.


The uncontrollable loss, small or large, of bladder or bowel control, resulting in leakage of their contents.

Lower esophageal sphincter

A circular band of muscle between the esophagus (gullet) and the stomach.


Inflamed nasal passages due to an immune reaction to an allergen such as pollen or dust. Symptoms include a watery nose and itchy eyes and nose.

What happens during the procedure?

Botox is administered as an injection to select areas to cause the desired effects. Different doses and concentrations of Botox are used depending on the reason for treatment. The injection is made using a fine needle, often just under the skin to reach superficial muscles. When performed for cosmetic reasons, it is commonly done in a medical clinic and does not need an anesthetic. However, when it is used for other medical reasons, it is often done as part of another procedure, which may need an anesthetic. Your doctor can discuss the exact situation that suits your condition.

It is advised that Botox be injected by a qualified medical professional, or at least under their supervision, as there can be certain side effects from incorrect administration.

What happens after the procedure?

The treatment commonly takes only a few minutes to administer. When it is done for cosmetic reasons, often you will be allowed to continue with your daily activities within an hour of receiving the treatment. There may be mild pain at the site of injections.

The treatment can take a few days for a noticeable effect. It is important to note that these effects typically only last between 3-6 months. Quite commonly, repeat injections are needed for ongoing effects. The timing of these repeat injections will depend on the reasons for treatment, the duration of effect from previous injections, and any side effects that you might have experienced. Your doctor can advise you on the likely treatment regime that you will need, including the number and timing of injections.

Risks and side effects

When performed by qualified professionals, Botox injections are generally safe. The most common side effect is localized pain and bruising at the injection site, which heals after a day or two. Also fairly common are headaches, which also usually resolve after a couple of days.

Rarely, serious side effects can occur, including blurred vision and trouble breathing.

Other side effects that may appear after a Botox injection can include (but are not limited to):

  • Drooping eyelids and eyebrows;
  • Muscle weakness;
  • Nausea;
  • Tiredness, sleep problems;
  • Skin tightness, and;
  • Respiratory tract infections and flu-like symptoms.


There has been little research on the effect of Botox on unborn fetuses and newborn infants. Botox so far appears to have no harmful effects during and after pregnancy, but proper medical trials have not been performed on pregnant women to fully evaluate the risks. Women who are pregnant, about to become pregnant, or breastfeeding and are considering cosmetic Botox treatment are advised to consider the decision carefully and consult their doctor. Often pregnancy has a natural effect of filling in facial wrinkles, so may reduce the desire for treatment during this time.

FAQ Frequently asked questions