Antiperspirants reduce sweat. Aluminum chloride compounds, such as aluminum chloralhydrate and aluminiumzirconium tetrachlorohydrex are the most effective antiperspirant agents you’ll find in conventional antiperspirants today.
Aluminum is a heavy metal that most of us are exposed to daily. It is a naturally occurring element from the earth and is used in the manufacturing of paints, cars, propellant, fuel additives, over the counter medications (like antacids), soda cans, aluminum foil and even your antiperspirants.
Aluminum compounds in antiperspirants combine with sweat, changing the pH of the aluminum salts and form a gel-like plug on the top of the sweat gland. This is what prevents the sweat from escaping to the underarm, keeping it dry.
While this may sound like a good thing, preventing your underarms from sweating traps sweat in the sweat gland causing it to be absorbed into the dermis layer of the skin. Although this amount of sweat in the dermis layer of the skin is probably not harmful it is not the way your body is designed to work.