antiöstrogen

Anti-estrogen is a general term for substances that block or reduce the effects of estrogen in the body. Estrogen is a primary female sex hormone, but it is also present in males and plays a role in various physiological processes in both sexes. Anti-estrogens work through different mechanisms, primarily by binding to estrogen receptors, thereby preventing estrogen from activating these receptors.

The most common types of anti-estrogens are selective estrogen receptor modulators (SERMs) and aromatase inhibitors (AIs). SERMs, such as tamoxifen, can act as estrogen agonists (mimicking estrogen) in some tissues while acting as antagonists (blocking estrogen) in others. This tissue-specific action makes them useful in treating certain types of breast cancer, particularly hormone receptor-positive breast cancer, where they can inhibit tumor growth. Aromatase inhibitors, such as anastrozole and letrozole, work by blocking the enzyme aromatase, which is responsible for converting androgens into estrogen. AIs are also used in the treatment of hormone-sensitive breast cancer, especially in postmenopausal women.

Beyond cancer treatment, anti-estrogens have other medical applications. They can be used to manage infertility by stimulating ovulation, and some are employed in the treatment of gynecomastia (enlarged breast tissue in males). In the context of sports and bodybuilding, certain anti-estrogens are sometimes used to counteract the estrogenic side effects of anabolic steroid use, although this practice carries risks and is not medically supervised. Potential side effects of anti-estrogens can vary depending on the specific drug but may include hot flashes, mood changes, fatigue, and an increased risk of blood clots.