Either this shaper is supposed to take two to get it on or it runs a little small. It cuts under the arms and really is tight. I assumed it was supposed to be that way, because it does hold you in and improves the figure. I just can't wear it very long because of the cutting under the arms. I probably should have returned it and got a large, but I know that a large is too big for me in anything. I like it, but it sits in my dresser most of the time. Maybe, if I lose a little weight, it will fit better.