Why You Should Apply Antiperspirant at Night

Last updated: July 2009

So-called clinical-strength antiperspirants contain the highest amount of sweat-controlling ingredients of any products available over the counter. They come with instructions that they be applied before bed for "maximum" protection from wetness and odor.

The leading clinical-strength products, Degree Clinical Protection and Secret Clinical Strength, cost $8 and up. That's more than twice the price of most regular-strength formulas, according to recent data from Information Resources, a Chicago market-research firm.

But even regular-strength antiperspirants work best when applied to underarms at night, experts told us. Bedtime application "really is the best way to use an antiperspirant," says David Pariser, M.D., president of the American Academy of Dermatology.

At night, when people perspire less, more of the antiperspirant's aluminum-based active ingredient is pulled into the sweat ducts. Because there's more antiperspirant present, it more effectively plugs pores.

That signals the sweat glands to reduce or stop perspiration. The effect lasts 24 hours or possibly longer, even after morning bathing. Eventually, the antiperspirant washes away. Blocking perspiration by plugging pores might sound unhealthful, but it's not, medical experts we consulted said.

Bottom line. If you're worried about excessive perspiration, apply a regular-strength antiperspirant at bedtime. If that's insufficient, switch to a clinical-strength product. If you're still concerned, talk with your doctor about the possibility of prescription options.