My son asked me this one. I thought I knew the answer but wanted to be sure. Here it is. Deodorants contain a fragrance or scent designed to mask odor. Noone likes body odor or wants to smell like they live in a room full of fitness equipment. Antiperspirants may or may not contain a scent and are designed to stop sweat from forming by blocking the sweat ducts. Both are available in many forms including solid, gel and spray. It is healthy to sweat because toxins come out in sweat. Which one works best for you depends on your lifestyle.