I don’t use anything but water under my arms. I found that after a while my armpits stopped smelling as bad. Maybe I’m just lucky. It’s all about bacteria. The sweat itself has no odor but the bacteria unde your arms feast on the sweat and starts producing smelly “farts”. I found that over time I build up bacteria that doesn’t smell and bacteria that actively remove any smel, so if I smell from stress sweat it’ll dampen down quite a bit over the following hour or so. Treat your armpits like a sour dough in your fridge. It’s a set of healthy bacteria you don’t want to accidentally kill. Interesting enough if I use soap to wash every day my armpits starts smelling stronger again so for daily wash I basically just use a lot of water and rince each armpit for a solid 30 sec to a minute each rubbing with my hand. Soap kills the good bacteria too and makes it worse. If you use any only use a tiny little bit. I also found that shaving my armpits makes me smell so much more and it’s uncomfortable too because I can feel the sweat drip down because it has nothing to cling too and cool you down which is exactly what it’s ment to do, so I basically just let my hairs be and it helps me sweat less and smell less. I’m lucky I don’t have that much hair but I’d assume it could be trimmed rather than shaved for many. There’s a reason we have hairs under our arms and they do serve an Important function. For me gone are the days of yellowed t-shirts from deodorant and Gone are the days of allergy inducing perfume.