Letrozole is an anti-estrogen of the Aromatase Inhibitor (AI) family and is one of the most potent and powerfully effective of all AI’s. In fact, its potency is sometimes too much for some to handle when used for off label use. Letrozole first gained U.S. FDA approval in 1997 and would hit the market under the brand name Femara through Novartis. Although Femara is the dominating trade name of the AI, unlike most AI’s it is the only one generally known by its chemical name Letrozole far more commonly than its dominating brand name. Letrozole was first developed in an effort to combat breast cancer in post-menopausal women. In fact, it would prove to be virtually identical to the already popular AI in Arimidex (Anastrozole). While intended for breast cancer treatment, like many AI’s, it has found a welcomed home among anabolic steroid users. Letrozole is one of the most commonly used anti-estrogens among steroid users during steroid use to combat possible estrogenic related side effects. It is so effective as an anti-estrogen in this regard many anabolic steroids have effectively reversed gynecomastia symptoms with Letrozole.

Letrozole Functions & Traits:
Letrozole is an AI, which holds the purpose of blocking the aromatase enzyme, which is in turn responsible for the production of estrogen. By inhibiting estrogen production, this lowers total serum estrogen levels in the body. This will be useful to the breast cancer patient on the basis of such cancer often feeding off the estrogen hormone. It will be beneficial to the anabolic steroid user as excess estrogen often leads to some of the most commonly associated side effects of anabolic steroid use. Letrozole also carries the ability to increase natural testosterone production through an increase in Luteinizing Hormone (LH) and Follicle Stimulating Hormone (FSH). There have been physicians who have chosen Letro as it’s often known to treat low testosterone conditions, but this is normally not the preferred method of treatment. Without question, when it comes to low testosterone treatment exogenous testosterone is generally the only thing that makes sense. However, Letrozole can be useful in such a plan in conjunction with exogenous testosterone in order to combat possible side effects. We will look into this in the effects section.

Effects of Letrozole:
Letrozole as an anti-estrogen is extremely beneficial to breast cancer patients. Many forms of breast cancer actively feed off the estrogen hormone. By inhibiting the production of estrogen, which in turn lowers the amount of circulating estrogen in the body, this has the ability to starve the cancer. For years Nolvadex was the preferred form of treatment for this purpose. Nolvadex actively binds to the estrogen receptor, thereby preventing estrogen from binding. However, it does not inhibit or lower production. Nolvadex is still extremely valuable in breast cancer treatment plans, but many physicians, especially in extreme cases have begun to use AI’s first. Once the cancer is in remission, at this stage a SERM like Nolvadex may replace the AI in an effort to protect against the cancer reappearing. For the anabolic steroid user, the same anti-estrogenic effect provided by Letrozole is tremendously beneficial. Many anabolic steroids have the ability to increase estrogen levels due to testosterone’s interaction with the aromatase enzyme. As estrogen levels rise, this can lead to gynecomastia and excess water retention. If water retention becomes severe, this can in turn promote high blood pressure. While many anabolic steroids have the ability to aromatize and promote an increase in estrogen, not all anabolic steroids carry this ability. However, many common steroids carry this ability including Methandrostenolone (Dianabol) as well as all forms of testosterone. The Nandrolone (Deca Durabolin, Durabolin, NPP, etc.) and Boldenone (Equipoise) hormone also carry the ability to aromatize to a degree. Nandrolone will aromatize at approximately 20% the rate of testosterone and Boldenone at approximately 50%. While both aromatize significantly less than testosterone, it is enough to promote estrogenic related side effects