We've All Been Putting On Deodorant At the Wrong Time

Like most people, you’ve probably spent your entire life applying deodorant in the morning, and if you have, you've been doing it wrong. It turns out there’s plenty of evidence to suggest that the best time to apply deodorant is at night, right before you go to bed. To clarify, this apply-at-night rule covers only deodorant containing antiperspirant. The function of deodorant without antiperspirant is to kill or mask odor-causing bacteria, not to actually reduce how much you sweat. Antiperspirant, on the other hand, is designed to temporarily plug your sweat pores and reduce the amount of perspiration expelled, keeping your armpits dry and thus inhibiting odor-causing bacteria growth. So, why is it more effective to apply antiperspirant deodorant at night? When you're less active — as in sleeping — your body temperature drops, causing you to sweat less. This lack of moisture enables your body to more readily absorb the active ingredient in most antiperspirants: aluminum. It’s easier for the aluminum to penetrate the skin when it doesn’t have to wade through the very thing it’s working against. Overnight, your skin will have more time to absorb the antiperspirant, making it more effective than if you apply it immediately before rushing around to get ready for the day. So what if showering in the morning is a non-negotiable for you — can you still follow this rule? Yes. Because you’ve given the antiperspirant sufficient time to penetrate and plug your sweat pores overnight, it’s not resting on the surface of the skin, leaving it susceptible to being washed off. For those who may worry about aluminum being a contributing factor to Alzheimer’s disease, multiple small and large scale studies have failed to find a convincing causal association between aluminum exposure in humans and Alzheimer’s disease.