Why are antiperspirants best applied at night before bedtime?

March 11, 2015

dermatologists have all experienced the patient who comes in stating that no antiperspirant works, even prescription aluminum chloride solutions. So what do you tell them? Read to learn more.

Zoe Diana Draelos, MDI am sure dermatologists have all experienced the patient who comes in stating that no antiperspirant works, even prescription aluminum chloride solutions.  This is a challenging patient because most of the sweating considered obnoxious is under emotional control and involves the palms of the hands, soles of the feet, armpits, and face.  Many of these of patients are not willing to undergo the discomfort or financial investment for botulinum toxin.  One suggestion that the dermatologist might offer is a method for optimizing antiperspirant preparations in the OTC market.

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The biggest reason antiperspirants fail is that they are not on the skin long enough to produce a coagulated keratin plug in the sweat duct to inhibit the release of sweat onto the skin surface.  Patients may use an antiperspirant for 2-3 days and then claim failure, when it takes 10 days of antiperspirant use to achieve a substantial keratin plug.  So, the first piece of advice the dermatologist should offer is that an antiperspirant must be used a minimum of 10 days prior to determining if success has been achieved.  In addition, the antiperspirant must be used on a daily basis to maintain the plug, which will disappear 14 days after the last application.

Finally, it is important for the skin to be dry when the antiperspirant is applied otherwise sweat will dilute the antiperspirant and it will fail due to insufficient concentration.  This is why bedtime application is best.  At night, activity is at a minimum and usually sweating is also reduced allowing the antiperspirant more time to contact the skin surface in higher concentration.  OTC antiperspirant formulations labeled “clinical strength” have a higher concentration of the active agent and while designed primarily for armpit use, can be applied to the palms, soles, and forehead at bedtime without problem.

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