Aromasin (Exemestane) is a steroidal suicide aromatase inhibitor, which means that it lowers estrogen production in the body by blocking the aromatase enzyme, the enzyme responsible for estrogen synthesization. (1)(2)(3). This stuff was developed to fight breast cancer in post-menopausal women, who need a particularly aggressive therapy, and for whom first line defenses such as SERMS (Tamoxifen) have not worked.

Aromasin and Side Effects

Aromasin averages an 85% rate of estrogen suppression (4), so it´s clearly a very effective agent for bodybuilders and other athletes wanting to avoid estrogen related side effects such as gyno, acne, or water-retention brought on by aromatizing steroids. Specifically, Exemestane dose this by selectively inhibiting aromatase activity in a time-dependent and irreversible manner.

As with most of the compounds in this class, it also causes a reasonable rise in testosterone levels (6), and as you may have guessed, this rise in testosterone means that Exemestane can also cause androgenic sides(8)(9)(10). You need to take Exemestane for a week to reach steady blood plasma levels of it, and exemestane has a ½ life of 27 hours (12.).

The ability of exemestane to lower estrogen levels by the aforementioned 85% makes it a very nice choice for use in any cycle where aromatizing steroids are used. In addition, since it´s not too harsh at all on blood lipid profiles, it´s a very good choice for longer cycles. It´s ability to raise both testosterone levels also seem to suggest that it would be a very nice addition to a Post-Cycle-Therapy (PCT).

Source: steroid.com