Need to take control of your hormones? Find a large selection of the best anti estrogens, also known as estrogen blockers or aromatase inhibitors. These estrogen blockers are used as part of a PCT after prohormones or as a stand alone to help lose weight by reducing the amount of estrogen in the body. During your post cycle, your natural testosterone will increase, but estrogen can rise as well. That's when Estrogen Blockers can help keep it down.