Botulinum toxin is released by the bacteria Clostridium botulinum and causes paralysis as the toxin blocks nerve signals to muscles. Botulinum injection is the most common cosmetic procedure worldwide.
Anyone who can give consent can have the injections, except for patients who had a prior allergic reaction to botulinum injections, those with infections or redness in areas to be injected, and pregnant and lactating women. Those with diseases of the neuromuscular junction should also avoid this procedure.
The desirable effect of botulinum is the weakening of a muscle or a group of muscles which make an undesirable expression (like frowning).
The most common side effect is mild bruising and some soreness on the injection site. A temporary headache may also ensue. Other unwanted side effects are the so-called Spock’s eyebrows in which the lateral part of the eyebrows would arch up, in response to the lack of movement in the inner eyebrow area. Eye muscles may also be affected leading to ptosis or drooping of the eyes, or ectropion, the turning out of the lower lid. When wrinkles around the lips are treated, some patients may have difficulty using a straw. Facial asymmetry may happen, and speech may be affected. When the injections are done on the neck area, difficulty in swallowing may be experienced. All these, however, are reversible and self-limiting.
The toxin lasts for 4-6 months as the body is able to naturally get rid of the toxin. It is imperative that this time period should pass before getting another injection. Too frequent injections may lead to the development of antibodies to the toxin, which will render the botulinum toxin injections ineffective for its cosmetic purpose. So, twice to thrice a year is reasonable, as long as the effects of the toxin have totally worn off already.