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. For the steroid using male, Anastrozole shows great potential. Up to this point, drugs like Nolvadex and Proviron have been the weapons against excess estrogen. These drugs do prove quite effective, but Anastrozole makes the job much more efficiently, and with less hassle. Anastrozole blocks the action of estrogen at the receptor, not its actual endogenous production. The effects of Anastrozole can be 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. In studies that have been done, Anastrozole has been shown to reduce estrogen in the body by roughly 50%. This is a good result for bodybuilders, because some estrogen is needed in order for the full anabolic benefits of the steroids being taken to be achieved. These results are the same with a dosage of 5mg a day as they are with a dosage of 1mg a day, meaning that in most cases, a half tablet a day will be sufficient for estrogen control throughout cycle. Anastrozole is an aromatase inhibitor which works by blocking the aromatase enzyme in the body, thus limiting the amount of estrogen buildup that takes place. This compound has great benefits to bodybuilders and athletes who use aromatizing steroids such as testosterone. Typically, bodybuilders using Anastrozole will begin taking it the day they start their cycle, and will run it throughout the duration of steroid administration. It is also important to point out Anastrozole’s ability to increase testosterone in the body. Some studies have shown that natural testosterone levels have increases as much as 60% after the use of this substance for seven days. Because of this, bodybuilders find this drug extremely effective during PCT where as they are trying to elevate natural levels as much as possible in order to avoid a post cycle "crash".