When I climbed Denali, one of the other clients was a dermatologist. He wanted volunteers to wipe one foot each night with alcohol, and put a special prescription antiperspirant on the other foot. He wanted to see whether the foot with the antiperspirant would be noticeably dryer or warmer. Everyone volunteered to participate. Nobody noticed much effect at lower elevations. When we got higher and several of us started wearing vapor-barrier socks, we immediately noticed a difference. I reported my one dry foot and used the antiperspirant on both feet after that. I don't know what that antiperspirant was, but it definitely worked.
