Botulinum toxin

Botulinum toxin, widely known as Botox (after one of its brand names), is a protein produced by the bacterium Clostridium botulinum which, injected in very small doses, temporarily relaxes the muscle it is applied to. In aesthetics it is used to soften expression lines; in medicine, to treat many neurological and muscular conditions. It is one of the most commonly performed aesthetic procedures in the world.

How it works

The toxin blocks the release of acetylcholine, the neurotransmitter the nerve uses to tell the muscle to contract. The treated muscle relaxes and the skin above it stops creasing, so dynamic wrinkles soften. The effect is local and reversible: over time the nerve forms new connections and the muscle regains its activity.

There are several serotypes; aesthetics almost exclusively uses botulinum toxin type A, sold in different formulations. It is a prescription medicine and may only be administered by a doctor.

History

In the 19th century the German physician Justinus Kerner described botulism and already suspected possible therapeutic uses. In the 1970s the ophthalmologist Alan Scott began using it to treat strabismus. In the late 1980s the Canadian doctors Jean and Alastair Carruthers noticed that patients treated for eyelid spasms saw their frown lines improve, which opened up its aesthetic use. It was approved for frown lines in the United States in 2002.

Uses

• Aesthetic: forehead lines, frown lines and crow’s feet; lifting the tail of the brow; neck bands; preventing wrinkles (preventive Botox).
• Functional: bruxism and masseter hypertrophy, gummy smile, excessive sweating (hyperhidrosis), chronic migraine, spasticity, blepharospasm and strabismus.

Contraindications

It should not be used during pregnancy or breastfeeding, in neuromuscular diseases such as myasthenia gravis, if there is infection in the area or allergy to any component. It is also not advisable for people with unrealistic expectations.

Side effects

They are generally mild and temporary: small bruises, pain at the injection site and headache. If the toxin spreads to neighbouring muscles it can cause temporary drooping of the eyelid or brow, asymmetry or a stiff look, which disappear as the effect wears off.

Duration

The effect starts to show within a few days, is complete at two weeks and usually lasts three to six months, depending on the area, the dose and the person.