Exemestane has a steroid skeleton and can inhibit the aromatase inhibitors. This prevents the synthesis of estrogens from androgens in non-ovarian tissues. This effect makes hormone-dependent (estrogen receptor-positive) breast cancer treatable. At present, it is only used if tamoxifen is insufficient. In sports, it is abused by the almost dose-independent achievable dominance of male hormones. Exemestane has no gestagenic or estrogenic effects.