Why so much underarm sweat?

I have always had a problem with underarm wetness. My mother, too. Both of us have struggled our whole lives to find an antiperspirant that actually works. I buy cheap shirts because they don’t last long before the smell sets in for good.

Winter is especially annoying because I am wearing more layers and even when my temperature is comfortable-to-cold I get embarrassing pit stains. Whether this is stress sweat, a result of my body temperature/the airflow around my skin, hormones, or something else, I am not sure. It’s not always, but more often than not.

If I wear a suit at work, I have to wear undershirts to catch the wetness and hope my blouse and blazer fabrics don’t touch and transfer it all the way through. My best luck at hiding it is with baggy tops that don’t come near contact with my underarms, but that’s awfully limiting, especially in a professional environment. And I still sweat in them, too.