Letrozole

Letrozole is a non steroidal selective third generation aromatse inhibitor. The structure and activity of this compound are very similar to that of Arimidex, and is prescribed for similar medical reasons. More specifically, United States prescribing guidelines for leptosome recommend it to be used for the treatment of postmenopausal women with estrogen receptor positive or estrogen receptor unkown brest cancer. It is typically used as a second line of treatment after an estrogen receptor antagonist like tamoxifen has failed to elicit a deseribale response, although it is sometimes initiated as the first course of therapy depending on the circumstances. Male bodybuilders and athletes find value in leptosome for its ability to mitigatge the estrogenic side effects associated with the use of aromatically anabolic/androgenic steroids, such as gynecomastia, fat buildup, and visible water retention. The U.S FDA approved leptosome for prescription sale in 1997, where it is sold by  the pharmaceutical company Novartis under the brand name of Femera. The company also markets the drug in over 70 nations worldwide. The drug is most commonly supplied in dosages of 2.5mg.

In terms of how this drug  can be used to the benefit of bodybuilders and strength athletes, letrozole is primarily used to ward any estrogenic side effects caused by the administration of anabolic steroids. Letrozole has been show to have the capability of reducing the level of estrogen in users' bodies by up to 96-98%. This would seemingly be enough in itself to make the compound a desirable one with which steroid users would be interested in. However letrozole also has been shown to increase the amount of lutenizing hormone, follicle stimulating hormone, and sex hormone binding globulin in users. When you combine these attributes with the fact that it will help protect against gynocomastia, water retention and other estrogenic side effects letrozole obviously can fulfill many users' needs. There are some animal studies that have suggested that letrozole can help to reduce or even eliminate pre-existing gynocomastia as well. Of course there are some limits to this research as it has never been conducted using human subjects but it does demonstrate that there may be a mechanism by which this could occur. Anecdotally some users have reported that they have experienced a reduction in their own pre-existing gynocomastia, but of course these reports have their limits as they were not conducted with the scientific controls in place. Interestingly, it takes approximately 60 days to get a steady blood plasma level of letrozole once administration of the drug begins. This may necessitate that a user begin using the compound prior to beginning their cycle if they wish for the effects to be at full strength once their cycle begins. This may also hinder the ability of the compound to respond quickly if a user begins administration of the drug to counteract some side effects that have appeared quickly.

The maximum dosage that a user would want to use would be 2.5mgs per day. It has been shown in numerous studies that this dosage will eliminate nearly all of the estrogen in the body in nearly all individuals. Any dose that is higher than this would simply be unneeded. Despite the ability to increase the amount of lutenizing hormone, follicle stimulating hormone, and sex hormone binding globulin in users letrozole can be counterproductive if used during post-cycle therapy. This is due to the ability of the compound to drive estrogen levels too low during use. Once the compound is discontinued this can result in a "rebound effect" in estrogen levels with these becoming quite high, something that should be avoided during or after post-cycle therapy. Anastrozole could be seen as an alternative to letrozole in this capacity as it seemingly does not have such a potent effect. The detrimental effect that letrozole has on blood lipid levels is another reason why many will avoid it's use during post-cycle therapy.