Letrozole represents an oral non-steroidal aromatase inhibitor which is used for the treatment of hormonally-responsive breast cancer after surgery. This medication works by decreasing the amount of estrogen produced by the body. It also used to help prevent the cancer from returning. In women it especially efficient in treating tumors that contain estrogen receptors that are classified as estrogen receptor-positive tumors. For athletes and bodybuilders, it is a drug used to combat the estrogenic side effects of anabolic steroids like water-retention, acne and gynocomastia. It will also raise Testosterone levels because of the lowered estrogen in the body.
Letrozole is probably one of the most powerful aromatase inhibitors used nowadays by bodybuilders and athletes. Besides reducing the estrogen levels it increases the amount of lutenizing hormone and follicle stimulating hormone. In one male test subject Letrozole was able to reduce estrogen levels to undetectable levels, and in another clinical study done on men of different ages, intravenous administration of Letrozole lowered Estrogen by 46% in the young men tested, and 62% in the elderly subjects. Letrozole is often used with strong aromatizing androgens such as Methandrostenolone or Testosterone and the result shows that gynecomastia and water retention can be effectively blocked.
An important fact is that it takes 60 days to get a steady blood plasma level of Letrozole once administration of the drug begins, so bodybuilders and athletes often should begin using this drug before the beginning of the cycle if they wish to obtain the maximal result. Side effects from Letrozole include a lowered sex drive and continuous use can lead to lowered lipid function and an impaired immune system. Other side effects like hot flushes and hair thinning can be present, and would no doubt be much more severe in pre-menopausal patients.