Aluminium chloride is an effective antiperspirant that is applied to the skin to control severe excessive sweating hyperhidrosis it works by blocking the sweat glands this causes the pressure of fluid within the sweat glands to rise to the point where it shuts off sweat production the antiperspirant is applied before going to bed at night and should be washed off in the morning it should not be reapplied during the day over time sweating will stop during the day and the number of times you