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 3 levels of protection to help sufferers manage their excessive sweating. Certain Dri extra-strength clinical antiperspirant & deodorant is extra effective & may be more gentle on sensitive skin. The active ingredient aluminum sesquichlorohydrate in Certain Dri extra-strength clinical has been shown to provide up to 72-hour protection for people with hyperhidrosis. 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 or shaving or on broken or irritated skin.