Letrazole Femera 2.5 mg - 30 tabs

Femara (letrozole) is a type II (non-steroidal) third generation aromatase inhibitor. Clinically it is used to treat postmenopausal women with either estrogen receptor positive or estrogen receptor unknown breast cancer.

In women, tumors that contain estrogen receptors are classified as estrogen receptor-positive (ER+) tumors. For Letrozole to be prescribed, a given tumor must have been diagnosed as estrogen receptor positive or estrogen receptor unknown.

In the world of bodybuilding it is used to reduce or eliminate excess estrogen caused by the use of aromatizing steroids.

Background

Letrozole was originally sold under the brand name Femara, and produced by the pharmaceutical house Novartis. It was patented on July 25th, 1997.

Action

Letrozole is known as a type II aromatase inhibitor, meaning, in simplest terms that it attaches to the aromatase enzyme and prevents it from converting androgens to estrogen. In slightly more complex terms, estrogens are produced by the conversion of androgens through the activity of the aromatase enzyme, and letrozole actually inhibits the production of estrogens in by competitive, (reversible) binding to the heme of the relevant cytochrome P450 unit.

Technical Data

Letrozole is currently the most powerful aromatase inhibitor available. In women with breast cancer, it has been shown to reduce estrogen levels by 98% or more. However, it’s use and benefits are not limited to eliminating estrogen in women.

In one male test subject Letrozole was able to reduce estrogen levels to undetectable levels (2), and in another clinical study done on both young and elderly men, intravenous administration of Letrozole lowered Estrogen by 46% in the young men tested, and 62% in the elderly subjects. Because estrogen is part of the negative feedback loop of the HPTA, Letrozole (and other anti-estrogens) are able to raise testosterone in male subjects. Letrozole was studied in men, and found to significantly increase LH levels to a 339 and 323% in the young and the elderly, respectively and Testosterone by 146 and 99%, respectively. (3) Letrozole was also able to produce a peak LH response to Gonadatropin Releasing Hormone equal to a 152 and 52% increase from baseline in either young or older men, respectively (3). In a similar study 0.02 mg of Letrozole increased testosterone by 45% after 2 days. (4) That same twenty micrograms of Letrozole was also enough, in one study done on men, to reduce estrogen levels by roughly a third.