The first antiandrogen to enter medicine, now a global hormone therapy staple

Countries & Cities · Published 2 October 2026 Swipe more like this →

In short: Discovered in 1961 as a progestin, cyproterone acetate became the world's first marketed antiandrogen in 1973. It works by blocking testosterone receptors and suppressing production, making it a cornerstone for treating everything from severe acne to prostate cancer across most of the globe.

Cyproterone acetate (CPA) functions through a dual mechanism: it acts as a progestin by activating progesterone receptors and as an antiandrogen by preventing testosterone from interacting with its biological targets. It also reduces the overall production of androgens by the gonads. Because of these properties, it is used in diverse contexts, including combined birth control pills (available since 1978), feminizing hormone therapy for transgender individuals, and the treatment of androgen-dependent conditions like seborrhea and hirsutism.

The drug's clinical utility varies significantly by dosage and population. In women, low doses in combination with estrogen can improve acne symptoms in 75% to 90% of patients. For severe hirsutism, higher dosages (25 to 100 mg/day) are often used, showing efficacy similar to other antiandrogens like spironolactone or finasteride. In transgender hormone therapy, CPA is a primary choice in Europe and globally because it consistently suppresses testosterone into the normal female range, unlike spironolactone.

Despite its widespread use, CPA carries notable risks and geographical restrictions. It is not approved for use in the United States, where alternatives like GnRH modulators or nonsteroidal antiandrogens are preferred. Furthermore, a 2020 European Medicine Agency warning highlighted that high doses (25mg daily or more) may contribute to meningioma risk. While it remains a palliative option for prostate cancer—the only steroidal antiandrogen still used for the condition—it has largely been superseded by newer treatments due to its safety profile and inferior effectiveness compared to combined androgen blockade.

For transgender individuals, medical guidelines have shifted toward caution; the World Professional Association for Transgender Health (WPATH) now recommends a maximum dose of 10 mg/day to minimize risks like blood clots, liver damage, and benign brain tumors while still achieving full testosterone suppression.

General information, not professional advice. Spotted an error? Flag the card or see corrections and complaints.

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