I've never worn compression tights until this purchase. To be honest, it took an act of god (perhaps the running god?) to get into them. There are instructions on the package stating how to put them on, but quite frankly, the scene in the house was like something out of a Saturday Night Live skit. Anyway, I am 5'2", 125 lbs, cycled for years, enjoyed microbrews for years (with no cycling), and consequently have fairly thick legs. Based on the opinions here, I bought a medium and am happy that I did. They were a tad binding around the back of the knees, but I have to admit, they felt good while running and my knees felt better when done. They were a little long for me, but hobbitses aren't known for their fairy-like legs. I'll defintely be purchasing another pair.