Aromaxyl (Exemestane) is a steroidal suicide aromatase inhibitor. It is very similar in structure and action to formestane, although it is significantly more potent in comparison. As a class of drugs, aromatase inhibitors offer an anti-estrogenic effect by blocking the enzyme responsible for synthesizing estrogens. Exemestane is approved by the FDA for the treatment of breast cancer in women, specifically in post-menopausal patients whose cancer has progressed following therapy with tamoxifen. Male bodybuilders and athletes often use the drug for non-approved purposes, namely to counter the estrogenic side effects associated with the use of aromatizable anabolic/androgenic steroids. This may include gynecomastia, fat buildup, and water retention. In some instances aromatase inhibitors may also assist this group with the loss of body fat and increases in muscular definition. Exemestane is one of the most potent aromatase inhibitors presently available. The most commonly cited data reports a lowering of serum estrogen levels by 85% on average in clinical studies with women. Exemestane is classified as an irreversible steroidal aromatase inhibitor. It has the chemical designation 6-methyl-enandrosta-1,4-diene-3,17-dione.
Exemestane is FDA approved for adjunctive treatment of postmenopausal women with estrogen-receptor positive early breast cancer with disease progression following tamoxifen. Therapy is initiated 2-3 years after tamoxifen has failed to elicit a desirable response, at which point tamoxifen is discontinued. Treatment with exemestane is continued for 2-3 additional years, and is completed after 5 years of cumulative adjunctive drug therapy.The dosage prescribed in all instances is one 25 mg tablet per day, taken after a meal. When used to mitigate the estrogenic side effects of anabolic/androgenic steroid use or increase muscle definition,male athletes and bodybuilders will commonly take 12.5 mg to 25 mg of exemestane per day. In some instances a half of a tablet (12.5 mg) taken every other day is sufficient to prevent the onset of estrogenic side effects.