I bought a unisex pair for myself (XS - I wear a Ladies 7.5) and they were too big. So, I gave them to my Mom (She wears an 8-8.5) and they fit her well. She loved them. I bought myself a ladies style size 6.5-7.5 and they still fit just a little big- perfect fit with socks. I am getting a pair for my Dad now. They are so comfortable, hand wash well and keep your ankles warm too. The only reason for the 4/5 star rating is the sizing runs big. Hope this helps.
In choosing a size for this product, there is no way to distinguish between men's medium and women's medium. Can't buy it.