Many of us put on deodorant after taking a shower in the morning, and while that may seem like the best way to start the day off fresh, antiperspirants are actually most effective when they're applied in the evening, Joshua Zeichner, MD, director of cosmetic and clinical research at the department of dermatology at Mount Sinai Hospital in New York City, told POPSUGAR.
Antiperspirant is often combined with deodorant and sold commercially, because while deodorant neutralizes odor, it's antiperspirant that prevents sweating. "Antiperspirants contain zinc salts that form a plug within your sweat glands, preventing sweat from reaching the surface of the skin," Dr. Zeichner explained. "At night, sweat levels tend to be lower than in the morning. This allows the antiperspirant to form a more effective plug in the sweat glands," ultimately keeping you drier longer.
So, if you suffer from excessive sweating, known as hyperhidrosis, applying deodorant before bed might help you avoid those embarrassing pit stains. If you tend to sweat more at night, rolling on antiperspirant may help, but Dr. Zeichner said sleeping in a cooler room will likely make more of a difference.