I know this is an old post , but i use to have dark underarms until i stop wearing deoderant that mask perspiration. like preventing sweating.
no more dove...
So i start wearing natural deodorant that allows you to sweat without stinking which comes from bateria. and noticed my underarms lightening up, and i stop shaving as well. Now my arms blends with my skin. Plus everytime you wax, your lifting off dead skin which is hard to do.
It really makes a bigg differrence, forget genectics!