Wrinkles :: BOTOX® :: How it Works
Because we are continuously making facial expressions, the underlying muscles are constantly contracting. Over time, the tissue around the eyes and mouth begins to sag from all the contracting and pulling, causing hyperkinetic wrinkles, or "wrinkles with motion". These wrinkles show up as glabellar lines and "crow's feet" around the eyes, "furrows" on the forehead, and fine lines around the mouth. During your treatment, your physician will gently inject BOTOX® directly into the muscles that cause these wrinkles.		How it Works Benefits FAQs Before & After Fact Sheet (DOC)

Because wrinkles are caused by overactive muscles, BOTOX® works by temporarily disrupting signals between the nerve and the muscle. Muscular movement occurs when a nerve transmits a signal to a muscle, causing it to contract or pull. The nerve ending is separated from a muscle by a small gap called a "synapse" or "neuromuscular junction." BOTOX® prevents the signal from crossing the neuromuscular junction, thereby allowing the muscle to relax and helping to eliminate the wrinkles that lie above. The effects of BOTOX® generally last 3-4 months.