Facial wrinkles are caused by sun (UV) exposure, repetitive contraction of facial expression muscles, and loss of skin collagen and volume. As skin become less elastic, the muscles pull and force the skin above to form a wrinkle, which becomes etched in the skin.
There are two types of wrinkles. Dynamic wrinkles form when the muscle is contracted. Static wrinkles are present even when the muscle is relaxed. Dynamic wrinkles progress to static wrinkles. Botulinum Toxin (BOTOX) blocks the release of acetylcholine, the chemical that a nerve uses to tell the muscles to contract.
Thus BOTOX weakens the muscle. With less muscle movement, the skin surface above it smoothes and wrinkles begin to soften. The effect is temporary and wears off in approximately 3 months.
Ophthalmologists have been longest users of BOTOX and have used it for two decades for the treatment of benign essential blepharospasm, hemifacial spasm, and strabismus.
Ophthalmologists began using BOTOX for facial wrinkles, and dermatology and others have followed. There have been an estimated 3.3 million treatments in 2005 alone. BOTOX injections in the brow region have a high patient satisfaction rate.