This will probably just make your palms feel greasy as well as sweaty. A better idea, says Pariser, is iontophoresis, which uses ionized water to conduct a very mild electrical current on the skin's surface. The mechanism behind iontophoresis isn't completely understood, but Pariser says the theory is that the electric current and mineral particles in the water act together to microscopically thicken the outer layer of the skin, blocking the flow of sweat to the surface. For the hands and feet, in-office iontophoresis treatments have had a success rate of over 80 percent, according to the American Academy of Dermatology.
One more thing: Unfortunately, the dermatological devices are too awkward and messy to use with armpits.