I took a risk and the Large fit me on the last column of hooks. My waist is about 40-41". There are a couple things that concern me. First, my torso is just a slight bit short for this product. So when I sit the wires kind of stab either my boobs or my pelvic area. another thing, as expected with wires, the wires begin to shape to body. . . but not in a good way. When I sit the wires can get a little uncomfortable. I would say maybe this is a good product for working out or wearing for a brief amount of time but not for whole day use.