Injections can be used to relax muscles. Principally, this application is to prevent frowning i.e. to stop the “corrugator” muscles from drawing the eyebrows together. This can be used to reduce other overactive facial expressions such as excessive brow-raising or scrunching up of the crows’ feet. As the muscles are selectively targeted, there is no danger of being expressionless. Originally, this type of therapy was used to treat facial spasms. Its cosmetic applications are more recent.
Currently, these injections are also being used to allow sufferers of cerebral palsy more freedom of movement (as the problem here is excessive tone in the muscles). The injected substance is produced by bacteria in the same way as many antibiotics are made. Sterilisation kills the bacteria leaving the pure product which is injected. You cannot catch a disease from the injection – there is no bacterium present. The relaxing effect is not instantaneous. It starts after 2-3 days and increases over a week or two. The effect lasts usually 3 to 8 months but will be better with successive treatments. Because unused muscles get weaker, subsequent treatments may be more infrequent and perhaps, eventually, unnecessary. Complications are very infrequent, localized and temporary.
The most significant complication would be if other muscles than those intended were affected as they would also be relaxed. This is best avoided by asking the patient to actively frown during the procedure so the appropriate muscle can be identified. Facial massages and knocks to the injected area should be avoided for a week after treatment. The tiny injections sting momentarily and the whole procedure takes but a few minutes.