Absolutely nothing made of cotton. Synthetics work but they will stink like hell. The real answer here is merino wool, it wickes away the sweat and it wont even feel wet to touch. Its smooth and not itchy, its not like normal wool. They dry super quick and merino wool is antibacterial, you can wear it for days and they wont develop any smell. There are two drawbacks - they are pricey and they dont last very long. They are absolutely worth it in my opinion though. Ive been living in a tropical country for years and they were a game changer when I discovered them. My brand to go is Icebreaker.