Certain Dri is the #1 over-the-counter brand that doctors recommend for their patients with excessive sweating, & is one of the original clinical antiperspirant brands. Certain Dri offers t3 levels of protection to help sufferers manage their excessive sweating. Certain Dri Prescription-Strength Clinical Antiperspirant contains 15% aluminum chloride & is one of the strongest, most effective antiperspirants you can buy without a prescription. Aluminum chloride is the strongest & most effective ingredient available & 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's important to apply sparingly at nighttime only to completely dry underarms. Don't use immediately after showering, shaving, or on broken & irritated skin.