Cyproterone Acetate in Gender-Affirming Care

Cyproterone acetate (brand name Androcur) is the most commonly prescribed anti-androgen for trans women in the Netherlands. It is a synthetic steroid with both anti-androgenic and progestogenic effects.

How it works

Cyproterone acetate blocks the androgen receptor and also suppresses the release of LH (luteinizing hormone) by the pituitary gland. This reduces testosterone production in the testes. The medication also has progestogenic activity and is prescribed at lower doses in women to treat severe acne and hirsutism.

Use in Dutch gender-affirming care

The Dutch Society for Endocrinology and the protocols of Amsterdam UMC list cyproterone acetate as the standard anti-androgen in feminizing hormone therapy, combined with estrogen. Internationally, it is also included in the Endocrine Society guideline (2017) and the WPATH Standards of Care version 8 (2022).

Side effects

Known side effects include fatigue, weight gain, mood problems, reduced libido and, in rare cases, liver damage. Mood problems and depressive symptoms are regularly reported in research and clinical practice.

EMA warning about meningioma (2020)

In 2020, the European Medicines Agency (EMA) introduced restrictions on the use of cyproterone-containing medicines because of an increased risk of meningioma, a benign tumor of the membranes surrounding the brain. The risk is dose-dependent and increases with long-term use at higher doses. The EMA advises treatment with the lowest effective dose and discontinuation if meningioma is diagnosed. The relationship between dose and risk is explained in detail on genderrisico.nl.

Alternatives

Internationally, alternatives include spironolactone (particularly in the US) and GnRH agonists. The choice between medications is partly determined by the side-effect profile, availability and patient preference. After an orchiectomy, an anti-androgen is generally no longer necessary.