Slimmer legs or just socks?

This are the socks I sometimes wear, before I go to bed. You are supposed to get slimmer legs by wearing them during the night.

I can't tell if it is working or not, but the socks are very tight, so it can feel a little bit uncomfortable in the beginning.
I don't wear the socks every night, because I am not 100% sure if it is healthy to do so...