Anastrozole (Arimidex) is the aromatase inhibitor of choice. The medicament is expediently used when substantial amounts of flavoring steroids are used or when one is prone to gynecomastia and using moderate amounts of such steroids. Arimidex does not have the side effects of aminoglutethimide (Cytadren) and can achieve high levels of estrogen blockade, much more so than Cytadren. It is possible to reduce too much estrogen with Arimidex and for this reason blood tests or less preferably saliva tests should be done after the first week of use to determine if the dosage is correct. As an aromatase inhibitor, Arimidex's mechanism of action, which blocks the conversion of aromatizable steroids to estrogen, is as opposed 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 when using Arimidex, there is usually no need to use Clomid as well, but (as mentioned in the section on Clomid) there can still be benefits to doing so. Using moderate doses of testosterone 0.5 mg / day is in usually sufficient and in some cases it can be too much.