Botox® Cosmetic for Facial Wrinkles Botox® Cosmetic is a relatively new treatment for some facial wrinkles. Botox® Cosmetic is purified botulinum toxin A. It works by blocking communication between muscles and the nerves. If a facial wrinkle is caused by an overactive muscle, Botox® Cosmetic can weaken or paralyze that muscle and the wrinkle will smooth out or disappear over time. Botox® Cosmetic is most useful for wrinkles in the glabellar area (between the eyes), the forehead and lateral to the eyes (crows feet). Botox® Cosmetic can also be helpful in some patients who have increased muscle tone in the platysma muscle in the neck that can cause unslightly banding. The dose used for facial wrinkles is very small. The toxin is injected directly into the muscle using a small needle. The injection is uncomfortable with transient stinging and burning. This usually passes within minutes of injection. There may be a little redness and swelling at the injection site for a few hours. The toxin then migrates along the muscle to the area when the nerves enter it (the neuromuscular junction) and blocks the transmission of nerve signals. It takes about 3 days for maximal effect. Botox® Cosmetic usually lasts for 3 to 4 months but may last longer with subsequent injections. I have had some patients enjoy benefits up to 9 months with their third or fourth treatment. This may be because the muscle atrophies to some degree or because the patient has retrained their facial expressions. Adverse effects from Botox® Cosmetic are unusual. When used in the area around the eyes, it is possible for the Botox® Cosmetic to affect the muscle that elevates the upper eyelid (the levator). This could result in a droopy eye for several weeks. Other possible adverse effects include prolonged swelling or redness at the injection site.