Only time I got stinky foot was touring with synthetic shoes & no socks. I assumed that synthetic shoes wouldn't harbor stink bacteria but was completely wrong. After 1-2 days in hot conditions feet stank so bad it was embarrassing to approach motel desk. Never had stink foot while using socks even with wide variety of shoe & sock materials. I bought Febreze Sport spray which seemed to help fight shoe stink residue but I couldn't tell for sure since I went back to socks anyway.