They are very tight and uncomfortable. I wear a size 9.5 so I took a size 10 but they are very tight and I feel like my feet are squeezing all over. Not sure if they will weaken over time but my first thought is to return them. I bought a similar pair from a store called Shemipro last year and they are very comfortable - I'm an international size 41 and would love to get another pair. I can't walk in them, they are so tight. The shipping was fast and I hope the free return is valid. It's a pain to buy shoes online.