Because the ultimate goal of a steroid cycle is to increase strength and muscle size, the associated spike in estrogen which accompanies steroids such as Testosterone is considered undesirable. In order to disassociate the two effects, two classes of drug are used. Medications such as Nolvadex or Clomid target the estrogen receptors. They make it more difficult for the estrogen to exert it’s influence within the body thus allowing the testosterone to act more freely. The second class is aromatase inhibitors such as Femara. They target the aromatase enzyme itself in order to prevent the production of estrogen in the first place. Sometimes, it’s not always clear which option you should go with or even what the differences are between the two. Lets clear that up a little.
In February 2009, Sports Illustrated reported that Alex Rodriguez tested positive for two AAS, testosterone and metenolone enanthate, while playing for the Texas Rangers in 2003. He claims to have purchased them over the counter, in the Dominican Republic . However, " boli ," as he referred to it, is an illegal substance in the Dominican Republic.   In an interview with ESPN two days after the SI revelations, Rodriguez admitted to using banned substances from 2001 to 2003, citing "an enormous amount of pressure to perform," but said he had not since then used banned performance-enhancing substances.   He said he did not know the name(s) of the particular substance(s) he was using, and would not specify whether he took them in injectable form.