Bought these to workout in, but they're less suited for working out and more suited as an everyday casual sock. There is little to no additional support where typically needed such as in the arch, and the material is thick and heavy. It definitely soaks up moisture rather than help wick it away. The socks are thick, which made my feet feel much tighter in my cycling shoes. I'm not sure why Amazon recommended them to be as I was searching for athletic training socks. These are definitely not worth it.
I'm a 9.5 mens. The medium fits like it was customized to both my feet. I run anywhere from 1k-10k daily, & I RELY on these socks for comfort & performance. It's my exclusive running sock. I don't normally write reviews, but once I read the first posting, I felt compelled to give a completely different perspective. The only negative is the price ... but it also makes sense ...in this case, you get what you pay for. Hope this helps. :)