Certain Dri is the #1 over-the-counter brand that doctors recommend for their patients with excessive sweating and is one of the original clinical antiperspirant deodorant brands. Certain Dri offers three levels of protection to help sufferers manage their excessive perspiration. Certain Dri Prescription Strength Clinical Antiperspirant Deodorant contains 12% Aluminum Chloride and is one of the strongest, most effective antiperspirants you can buy without a prescription. Other antiperspirants may have aluminum complexes at higher percentages, but they are not the same. Aluminum Chloride is the strongest and most effective ingredient available and is the #1 doctor recommended active ingredient for hyperhidrosis. This Certain Dri formulation stops excessive sweating for up to 72 hours. PLEASE NOTE: this item is intended for people with the medical condition hyperhidrosis, so it contains a strong active ingredient that may irritate the skin when applied incorrectly. It is important to apply sparingly at nighttime only to completely dry underarms. Do not use immediately after showering or shaving or on broken or irritated skin.