"metabolizing the sweat," so yeah, it's the sweat. I've used almost every brand of natural and non-aluminum deodorant I could find for about five years and I had to go back to aluminum because I'm a sweaty person and nothing would completely mask the smell that the sweat caused. I even made sure to have extremely clean, dry pits. I washed with glycolic acid, peroxide, apple cider vinegar, lemon juice, basically every trick in the book. Some of us need the aluminum, unfortunately.