Millions of people suffer from hyperhidrosis, or excessive sweating. Certain Dri is here to help. Certain Dri is the #1 doctor recommended brand for excessive sweating. Certain Dri Prescription Strength Roll-On has 12% Aluminum Chloride in its ingredients, making it the most effective antiperspirant you can buy without a prescription. Aluminum Chloride is the strongest and most effective active ingredient available in antiperspirants and is the same active ingredient in many prescription formulations. This deodorant helps stop excessive sweating for up to 72 hours. It is also certified cruelty-free by PETA. Because of the strength of this active ingredient, it is only available in roll-on form.