I am 5'4 and weight 120lb. Normally wear a size SM and I order a M since all the other reviews stated it a size smaller and this is true. I have only used it twice and have not seeing any difference yet, but perhaps its to soon. My only actual complaint would be the pants really don't cover entire abdomen. It only reaches about 2 inches below the belly button. I really wish for it to be high-waist like the picture.