Exemestane, sold under the brand name Aromasin among others, is a member of the class of antiestrogens known as aromatase inhibitors. Some breast cancers require estrogen to grow. Those cancers have estrogen receptors, and are called ER-positive.
Aromasin is an Aromatase Inhibitor (AI) which stops the conversion of Androgens into estrogen by disabling the aromatase enzyme once binded to it. It basically prevents the chance of developing breast tissue while on cycle (cycle dependent).
Aromasin (Exemestane) is usually used as an on-cycle estrogen control drug and during post-cycle therapy. It converts the muscle building testosterone to the female hormone estrogen. It will disable the aromatase enzyme for good as soon as it binds to it.
Aromasin is a medication used to treat breast cancer. Since, breast cancers require estrogen to grow. Those cancers have estrogen receptors (ERs) and are called ER-positive. They may also be called estrogen-responsive, hormonally-responsive or hormone-receptor-positive.
Aromatase is an enzyme that synthesizes estrogen. It inhibitors block the synthesis of estrogen. This lowers the estrogen level and slows the growth of cancers.