One of my best friends in high school had that problem. She was head majorette and was always so embarrassed when she'd have sweat rings on her uniform. After her Jr. prom pictures were ruined because you could see the sweat rings under her arms in her dress her mother took her to the doctor. They put her on some kind of pill to help, and it did. This was in the mid 80s so I'm sure there is something even better available by now. Sorry, I don't know the name of the drug but it saved her senior year in high school.