Arimidex (Anastrozole) is not a steroid. It is a tablet form anti-aromitase that is used by many body builders to help prevent bloating (edema) and Gynecomastia (bitch tit) associated with the use of testosterone and androgens. It can be used in place of Nolvadex ,Clomid, etc. Bodybuilders are using around .25mg to 1mg per day or .5mg to 1mg every other day and are having good success with it. The FDA approved uses are for the treatment of breast cancer in post-menopausal women with disease progression following tamoxifen therapy. Hypersensitivity to anastrozole are reasons not to use this drug. If you have these problems please inform your doctor. Common side effects are: shortness of breath, dizziness, diarrhea, vomiting, headache, hat flashes, weakness, cough, dry mouth, skin rash, sweating, abdominal pain and bone pain. Some less common symptoms are vaginal bleeding, weight gain, tiredness, chills, fever, breast pain, and itching. In case of an overdose, it is recommended to contact your poison control center. Anastrozole (Arimidex (Anastrozole)) is the aromatase inhibitor of choice. The drug is appropriately used when using substantial amounts of aromatizing steroids, or when one is prone to gynecomastia and using moderate amounts of such steroids. Arimidex (Anastrozole) does not have the side effects of aminoglutethimide (Cytadren) and can achieve a high degree of estrogen blockade, much moreso than Cytadren. It is possible to reduce estrogen too much with Arimidex (Anastrozole), and for this reason blood tests, or less preferably salivary tests, should be taken after the first week of use to determine if the dosing is correct. As an aromatase inhibitor, Arimidex (Anastrozole)'s mechanism of action -- blocking conversion of aromatizable steroids to estrogen -- is in contrast to the mechanism of action of anti-estrogens such as clomiphene (Clomid) or tamoxifen (Nolvadex), which block estrogen receptors in some tissues, and activate estrogen receptors in others. During a cycle, if using Arimidex (Anastrozole), there is generally no need to use Clomid as well, but (as mentioned in the section on Clomid) there may still be benefits to doing so.With moderate doses of testosterone 0.5 mg/day is usually sufficient and in some cases may be too much.