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Femara (Letrozole)Complete info about Femara (Letrozole)Letrozole is the chemical name of Novartis' selective third generation aromatese inhibitor (AI). This drug was developed to fight breast cancer by inhibiting aromatization. It is usually used as a part of an aggressive treatment in post-menopausal women to fight and reverse the spread of breast cancer after other treatments (such as tamoxifen therapy) failed. It's probably the most efficient product on the market for this purpose currently (5). It is very similar structure and action to it's predecessor Arimidex. Letrozole also does quite a few things which would be of interest to both bodybuilders and athletes. First, it has been shown to reduce estrogen levels by 98% or greater (1). In at least one documented incidence, Letrozole reduced estrogen in the test subject to undetectable levels, and increased LH, FSH and SHBG (4). Clearly this is all of interest to bodybuilders, as less estrogen in the body means less chance of certain side effects such as water-retention, gynecomastia, and acne. This makes Letrozole an appropriate choice for even the heaviest bulking or cutting cycles including harsh androgens. Also, if you are a competitive bodybuilder, letrozole is a must have product for contest prep; no other Ancillary compound will produce a dry and tight look like Letro will. An effective dose of Letrozole is .25-.5mg/day (I use .25mgs/day), but be forewarned, if you go over that amount, it can kill your sex drive. Also worth noting is that there's a rebound effect on your estrogen when you come off letrozol. Maximum inhibition of the aromatize enzyme has been found to happen at doses as low as 100mcg (2)! Letrozole's effects on serum lipids (cholesterol, both HDL and LDL) are, in the words of one researcher: "inconsistent." Clearly, however, you'll eventually suffer an impaired lipid profile and immune system if you keep your estrogen levels too low for too long. Your sex drive will also probably suffer from extraordinarily low levels of estrogen present. As previously mentioned, letrozole can be used to raise LH and FSH (which are hormones that signal your testes to produce more testosterone). It also, of course, will raise your testosterone levels (6) via this mechanism. Again, this is of interest to athletes and bodybuilders for obvious reasons. Letrozole can be used for post cycle therapy (PCT) to raise test levels, but for various reasons, tamoxifen may be a better choice. Still, I have successfully used letrozole for this purpose. How good is this compared with Aromasin and Arimidex, its two other main rivals? In non-cellular systems, letrozole is 2-5 times more potent than anastrozole and exemestane in its inhibition of the aromatize enzyme and activity, and in cellular systems it is 10-20x more potent! It also lasts quite a long time in your body, but takes awhile to get going--letrozole has a whopping 2-4 day (!) half life, and you need to take Letrozole for 60 days to get a steady blood plasma level (8). Those are impressive numbers, but here's one of the most interesting things about Letrozole: it may reduce/eliminate/reverse existing gynecomastia! In a study conducted on mice, gyno-like-changes in the mammary gland were totally destroyed! Here's a direct quote from that study: "Our results also indicate aromatize overexpression-induced changes in mammary glands can be abrogated (destroyed] with very low concentrations of the aromatize inhibitor, letrozole." (7) References
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