The area to be treated is placed into water. A gentle current of electricity passes through the water. A technician carefully and gradually increases the electrical current until you feel a light tingling sensation.
The therapy lasts about 10-20 minutes and requires several sessions.
How iontophoresis works isn't exactly known, but it's thought that the process somehow plugs the sweat glands and temporarily prevents you from sweating.
Iontophoresis units are also available for home use.