I bought his to wear for some medical tests and treatments. I'm 5'7" and weigh 125 pounds. The small fits like it was custom made for me. It's so incredibly comfortable that I'm going to go back and get more colors. The fabric is so soft, it's more comfortable than all of my other sweats and pajamas. I may live in these for the rest of my life! You will not be disappointed! Treat yourself to these in every color!