I bought this in 34DD, and i don't have to wear any extra bras or restrainers or anything, and I can run, do crossfit, and it works great. Like with any sports bra however, you can't wear it all day, and you have to replace it every year or so otherwise it stretches out. Try buying a size so that you have to hook the largest setting, that way as the bra wears you can tighten it and it lasts a little longer. Love it! I now have three I switch between!