I bought medium, and the waist band is tighter than necessary. Also, the lower part of the band tends to fold up onto the higher part of the band, leaving just half the width (and extra tension) touching my waist, which isn't comfortable and looks bad too. Not sure if this is because of the tightness, the thinness of the band, or both, but I won't be buying these again.
Waist band too tight, folds onto itself