Testolactone is a first generation non selective steroidal aromatase inhibitor, used clinically to treat estrogen dependant breast cancer. Its exact mode of funciton is unkown, but it is believed to inhibit the aromatase enzyme in a noncompetitive and irreversible manner. If so, this would be an activity that is very similar to that of Lentaron. This might also explain why cessation of the drug does not provide an immediate restoration of normal estrogen production. Like formestane, it takes several days after ceasing use for the body to replenish its enzyme levels. Testolactone was first approved by the FDA as a prescription drug back in 1970. It was an early anti estrogenic drug, exhibiting a moderately pronounced effect but failing to reach levels of high clinical success. As other more successful medications began to surface for the treatment of breast cancer, testolactone would not see the success that had been planned for it. Currently, the United States is the only country where the product has not been discontinued. Testolactone is most commonly supplied in tablets of 50mg.

Tamoxifen citrate is a non steroidal anti estrogenic drug, used widely in clinical medicine. It is specifically a selective estrogen receptor modulator of the triphenylethylene family, and posses both estrogen agonist and antagonist properties. As such, it may act as an estrogen in some tissues while acting as an anti-estrogen in others. In breast tissue the drug is a strong anti estrogen and as a result is commonly used in the treatment of estrogen related breast cancer in women. Tamoxifen citrate was first developed in 1962 by the pharmaceutical company ICI. It was made commercially available in the United States not long after, but its initial use was for the treatment of female infertility, a purpose for which the drug does not seem ideally suited for. It was not until 1977 that the FDA approved the drug for use in the United States for the treatment of breast cancer. The drug has been sold by ICI in a number of worldwide markets under the brand name of Nolvadex. The drug is most commonly supplied in tablets containing either 10mg of 20mg of the drug.

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.

Fulvestrant is a highly selective estrogen receptor antagonist. It exerts its action in the body not by targeting the production of estrogen, but by preventing it from exerting activity on the body. It does this by binding available estrogen receptors in a competitive manner, making them unavailable for circulating estrogens. This mode of action is very similar to Nolvadex and Clomid, although unlike these two agent fulvestrant does not have mixed agonist/antagonist properties. It is a pure estrogen receptor antagonist. This agent also stands out as the first inject able estrogen antagonist to catch the attention of the athletic and bodybuilding world. Although not widely used here, when applied it may be effective drug for mitigating the side effects of excess estrogen caused by anabolic/androgenic steroid use such as gynecomastia, fat buildup, and increased water retention. Fulvestrant was developed by the pharmaceutical company AstraZeneca. It was approved as a prescription drug in the U.S in 2002, and is sold under the brand name of Faslodex. The drug is indicated for the treatment of estrogen receptor positive breast cancer with disease progression following traditional anti estrogen treatment with drugs  such as nolvadex. The company has since expanded  its market for Faslodex to include over a dozen countries worldwide.

Toremifene citrate is an anti-estrogenic drug, specifically classified as a selective estrogen receptor modulator (SERM) with mixed agonist and antagonist properties. It is a non steroidal triphenylethylene derivative, similar in structure to both the drugs nolvadex and clomid. Toremifen citrate is used for the treatment of breast cancer in postmenopausal women with the estrogen receptor positive or estrogenic receptor unknown tumors. It works by attaching to the estrogen receptor in various tissues in a competitive manner, blocking endogenous estrogen from exerting biological activity. Toremifene citrate was first approved by the FDA as a prescription drug in 1997. It is sold in the U.S under the Fareston brand name, which is made by the pharmaceutical company Gtx Inc. Fareston is also available in over 25 other countries worldwide. Fareston is most commonly supplied in tablets of 88.4mg, which are labeled and equate to 60mg of toremifene base.

Raloxifene hydrochloride is a second generation selective estrogen receptor modulator (SERM) of the benzothiophene family. This drug is similar in its effects to the drug tamoxifen (nolvadex), exhibiting estrogen receptor antagonist properties in some tissues while acting as an estrogen receptor agonist in others. The main point of variation between the two drugs is their tissue selectivity. While raloxifene hydrochloride is a strong anti-estrogen in breat and uterine tissues, it appears to be estrogenic in bone. This allows it to protect bone density, mimicking the effects of endogenous estradiol. This is quite different than nolvadex, which is anti estrogenic in both breast and bone. In a role that novel for an anti-estrogen, raloxifene was approved by the FDA for the prevention and treatment of osteoporosis in post menopausal women. It is also being investigated for several other potential uses, including the treatment and prevention of cardiovascular disease. Raloxifene was developed by Eli Lilly & Company, and the FDA approved for U.S sale in 1997. Its first indictated use was as that of an osteoporosis treatment, owing to its ability to increase bone density. In 2007, the FDA expanded the indicated uses for the drug to include reducing the risk of invasive breast cancer in two  populations. Today, the drug is a fairly popular drug in clinical medicine, and is approved for sale in over 50 countries. The most common brand name is Evista and dominates the global market.

Aminoglutethimide is mainly identified as an inhibitor of adrenocortical steroid synthesis. Its primary function is to block the conversion of cholesterol to pregnenolone, which is required for the biosynthesis of adrenal glucocorticoids, mineral corticoids, estrogens, and androgens. Aminoglutethimide is a nonspecific inhibitor, and also blocks several other steps in steroid synthesis including hydroxylation at C-11, C-18, and C-21, and the aromatization of androgen to estrogens, The drug may be used clinically to treat estrogen dependent breast cancer, and to treat Cushing’s syndrome, which is a condition where the body overproduces the hormone cortical. The effect that Aminoglutethimide can have on cortical and estrogen production is what makes this a drug of interest to athletes and bodybuilders. The drug also works by inhibiting cortical production. While cortical is an essential hormone for life, its  levels may also vary greatly within “normal” ranges depending on the individual, their training and dietary status. Aminoglutethimide was FDA approved as an anticonvulsant drug in 1960 under the main trade name of Cytadren. Side effects were common with treatment, however, including drowsiness, dizziness, and partial loss of motor control. In 1966 reports of adrenal insufficiency subsequent to Aminoglutethimide use were reported. The drug was withdrawn from the U.S market as an anticonvulsant that same year due to its recently understood effects on the adrenal gland. The drug is most commonly supplied in tablets of 250mg.

Clomiphene citrate is an anti estrogenic drug that is prescribed to women to treat anovulatory infertility (inability to ovulate). In clinical medicine it is specifically referred to as a nonsteroidal ovulatory stimulant. The drug works by interacting with estrogen receptors, often in an antagonistic manner, in various tissues of the body including the hypothalamus, pituitary, ovary, endometrial, vagina, and cervix. One main focus is that the drug will oppose the negative feedback of estrogens on the hypothalamic pituitary ovarian axis, enhancing the release of gonadotropins (LH and FSH). This surge in gonadotropins may cause egg release, ideally leading to conception. Clomiphense is very similar in structure to the popular drug  nolvadex. Clomiphene citrate is a fertility drug with a substantial history of use in the United States. It first gaiined widespread acceptance during the early 1970s, and has been a drug common to the fertility practice ever since. The drug is now considered a standard medication for certain forms of fertility therapy, and has been adopted as such far outside the United States border. The drug is now presently available in most nations worldwide. The most two popular brand names for clomiphene citrate are Clomid and Serofen, although the drug can be found under numerous other trade names as well.

Exemestane is a steroidal suicide aromatase inhibitor. It isvery similar in structure and action to formestane, although it is significantly more potent in comparison. As a class of drugs, aromatase inhibitors offer an anti estrogenic effect by blocking the enzyme responsible for synthesizing estrogens. Exemestane is approved by the FDA for the treatment of breast cancer in women, specifically in post menopausal patients whose cancer has progressed following therapy with tamoxifen (nolvadex). Male bodybuilders and athletes often use the drug for non approved purposes, namely to counter the estrogenic side effects associated with the use of aromatizable anabolic/androgenic steroids. This may include gynecomastia, fat buildup, and water retention. Exemestane is one of the most potent aromatase inhibitors presently available. The most commonly cited date reports a lowering of estrogen around 85% on average in clinical studies with women. Exemestane was developed by Pharmacia & Upjohn, which gained FDA approval for sale of the drug in late 1999. They introduced it under the Aromasin brand name in early 2000. Although the drug proved to be effective in doses as low as 2.5mg per day in some patients, the company developed it in a standard and near universally effective dosage of 25mg per tablet. The company has since introduced the drug to many other nations under the same trade name of Aromasin.

Anastrozole is an anti estrogenic drug developed for the treatment of advanced breast cancer in women. Specifically, this agent is the first in a newer class of third generation selective oral aromatase inhibitors. It acts by blocking the enzyme aromatase, subsequently blocking the production of estrogen in the body. Since many forms of breast cancer cells are stimulated by estrogen, reducing levels of this hormone in the body may retard the progression of the disease. This is also the fundamental use of tamoxifen citrate (Nolvadex), except nolvadex blocks the action of estrogen at the receptor, not its actual endogenous production. The effects of anastrozole can be very substantial, with a daily dosage of 1mg capable of production estrogen suppression greater than 80% in treated patients. With the powerful effect this drug has on hormone levels, it is usually only prescribed to post menopausal women. Anastrozole was developed by Zeneca Pharmaceuticals, and approved for use in the United States at the end of 1995. The drug was developed as a new adjunct treatment for operable breast cancer in postmenopausal female patients, an area of medicine that had a long history of nolvadex use. Substantial date was needed to shit prescribing trends away from such an established medication treatment.