“Expression lines” are lines formed by the contraction or shortening of “expression muscles” that run perpendicular to these lines. For example, the frontalis muscle is resposible for forehead lines, the corrugator and procerus muscles for scowl lines, and the orbicularis muscles for crow’s feet and other lines around the eyes. Injecting expression muscles with botulinum toxin is an extremely safe and simple way to reduce if not remove expression lines, though it may sound scary, especially to those who associate botulism (severe food poisoning caused by eating insufficiently cooked meat). Botulinum toxin blocks the release of acetylcholine from the nerve ending, a chemical substance which causes the muscle to contract. It has been used in neurology for a few decades to treat muscle spasm such as tic. When it is injected in tiny amounts into specific muscles, it can inactivate them for months until the effect wears off. It takes 2 to 7 days before the effect can be noticed: Muscle movements become difficult if not impossible. The degree of muscle inactivity may fluctuate during the first month. The effect generally lasts for four to six months and may last longer with repeated treatment sessions as a result of

muscle “atrophy” or thinning. It is advisable to come back while the effect of the preceding session is not completely lost. Repeating within three months should be avoided as much as possible since it may increase the chance of developing antibodies to botulinum toxin, thus rendering this treatment ineffective. Serious side effects have never been reported. Loss of expression is not a concern if appropriate amounts are injected, though some appreciate the feeling of muscle relaxation achieved by more complete inhibition of muscle movements. Treatment of forehead lines is most often accompanied by undesirable effects, such as a heavy feeling in the forehead, difficulty with an upward gaze and droopy eyelids. As is with the desired effect, they are all transient. Asymmetrical eyebrow position may require an additional injection on the higher side. Several punctures are necessary per area, but the procedure is quick and the pain is quite bearable. Bruises may appear especially around the eyes, but they fade within a few to several days. Slight redness and swelling may persist for hours. Make-up can be used from the next day. Like after any procedure, UV protection is recommended for the following few weeks.