Garment photo belt

How to prevent underarm wetness? What type of deodorant works best? - sweater protection against moths

Well, I guess you could say I'm sweating, but no matter what I think I still use deodorant little wet spots on my arms. No smell, just a little flattering. Just do not let me use T-shirts Cute thin. I've heard about the strength and revenue protection against moisture, but Im not sure what I need. Am I just missing something or someone can help, the humidity?
Ideas?