Botox is applied to the forehead and its effect lasts for about 3 months. Botulinum toxin A (BOTOX®) or botulism toxin type A has been used by physicians since the early 1970s to temporarily relax muscles that cause excessive sweating in certain areas of the body such as underarms, feet, palms and face. This condition affects up to 20% of adults with age-related changes occurring due to hormonal decline, medications or side effects from other treatments such as radiation therapy for cancer. By blocking the release of acetylcholine at nerve terminals causing muscles not active enough produce sweat more than normal, BOTOX® helps reduce excessive perspiration on these areas without affecting overall function of those structures. After four years, users generally stop sweating altogether because there are no longer any nerves sending signals telling them they need water so their bodies do not secrete sweat anymore.