Letrozole is a drug from the group of aromatasemmer. It is taken orally. Letrozole was patented in 1989 by Ciba-Geigy under the brand name Femara and is used to treat primary and metastatic breast cancer in postmenopausal women.
Letrozole inhibits excessive aromatization of androgens to estrogens. The effect and strength is similar to that of the Anastrozol.
In the medical field, the dosage of the aromatase mixer letrozole is 2.5mg per day. However, in various clinical trials, it has been shown that a 75% suppression of estrogen production can already be obtained with dosages of 0.1 to 0.5 mg.
Frequently, bodybuilders use letrozole during the doping phase to counteract the estrogenic side effects. The dosages are usually well below those in the medical field, dosages of the reduction of estrogen-related side effects from 0.25mg to 1.25mg letrozole can be found every two days. Since the active substance Letrozole has a half-life of more than two days (about 50 hours), taking every other day is usually sufficient.