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 does not have the side effects of aminoglutheride and can achieve a high degree of estrogen blockade, much moreso than aminoglutheride . It is possible to reduce estrogen too much with Arimidex, 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’s mechanism of action — blocking conversion of aromatizable steroids to estrogen — is in contrast to the mechanism of action of anti-estrogens such as Clomid or Nolvadex , which block estrogen receptors in some tissues, and activate estrogen receptors in others. During a cycle, if using Arimidex, 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.

Arimidex is quite expensive . With moderate doses of testosterone 0.5 mg/day is usually sufficient and in some cases may be too much.