What does letrozole do?

Aromatase inhibitors are drugs that inhibit the enzyme aromatase. They are used to treating breast cancer in postmenopausal women and for the treatment of gynecomastia. Letrozole is a selective, reversible, non-steroidal aromatase inhibitor. The enzyme catalyzes the conversion of androgens to estrogens, including testosterone to estradiol. Come find out more about it.

How letrozole works

Letrozole works in three stages. In women, before menopause, aromatization occurs primarily in the ovaries. During menopause, the amount of estrogen produced there decreases from 25 to 100 mcg (depending on the phase of the cycle) to 5 to 10 mcg per day. Estrogen is also formed from the androgen dehydroepiandrosterone, which is formed in the adrenal cortex and in the fatty tissue, especially after menopause. For information about letrozole and true muscle building, click for more details. This extraovarian estrogen synthesis is an important growth stimulus in hormone-dependent breast cancer. It can be suppressed by aromatase inhibitors such as letrozole. Letrozole is then administered, for example, after a previous standard adjuvant treatment with tamoxifen. Only women with a postmenopausal hormonal status should receive letrozole. Letrozole itself has no gestagenic or estrogenic effects. There appears to be a slight androgenic effect due to a metabolite. However, their significance is unclear.

Use against the side effects of testosterone

Extraovarian estrogen synthesis is not only undesirable in brood cancer. In athletes who use anabolic steroids for doping purposes, it causes side effects such as gynecomastia. This can be counteracted by letrozole. In addition, letrozole - also due to the lowering of estrogen levels—is believed to promote fat loss and prevent water retention in bodybuilders during the accumulation phase.