The health stores sell a crystal deodorant there are several brands and they are very effective and best of all wont stain your clothes

Driclor deoderant is brilliant or else after your shower use talcum powder before you put on deoderant. And wait at least 15mins after your shoer to put on deoderant because if your still warm it'll just vanish

I use sure cream stick. It's the only one I can use which minimises sweating under my arms. I've been told that you can get botox for your arm pits which stops the sweat glands producing sweat! I personally don't like the sound of it. But it does work!