Cyproterone

Key facts

• Cyproterone blocks the effect of male hormones (androgens) on skin and hair follicles. Combined with the estrogen ethinylestradiol in a single tablet, it treats severe acne, excess facial or body hair, and hormonal symptoms of polycystic ovary syndrome (PCOS) in women.
• It's taken as a daily tablet, usually in a cyclical pattern similar to a contraceptive pill; visible improvement in skin or hair growth can take three to six months.
• Combined with ethinylestradiol, cyproterone carries an increased risk of blood clots (venous thromboembolism) compared with some other hormonal combinations. It must not be used in pregnancy: as an antiandrogen it can affect the genital development of a male fetus.
• Seek urgent care for leg swelling or pain, sudden shortness of breath, chest pain, or a severe headache with vision changes.

What cyproterone treats

Cyproterone-ethinylestradiol treats androgen-driven skin and hair problems in women: persistent acne that has not responded to other treatment, hirsutism (excess coarse hair on the face, chest, or back), and the oily skin and irregular cycles seen in PCOS. Taken correctly, it also prevents pregnancy. At much higher doses, cyproterone alone is occasionally used in men as part of advanced prostate cancer therapy.

How cyproterone works

Cyproterone occupies the receptors that testosterone and related hormones normally bind to in the skin and hair follicles, blocking their effect on oil production and hair growth. It also has progestogen-like activity that, together with ethinylestradiol, suppresses the hormone signals that trigger ovulation, which is why the combination also works as a contraceptive.

Before you take it

• Do not take cyproterone-ethinylestradiol if you are or might be pregnant, or if you have a personal history of blood clots, certain migraines with aura, or liver tumours.
• Tell your prescriber if you smoke, are over 35, or have high blood pressure, diabetes, or a family history of blood clots; these raise clot risk further.
• Enzyme-inducing medicines, such as some anticonvulsants and rifampicin, can reduce its effectiveness, including its contraceptive effect.
• This is a hormonal medicine with cumulative effects; it is not a fast fix, and improvement in acne or hair growth builds over months.

Side effects

Common effects include nausea, breast tenderness, irregular bleeding between periods, headache, and mood changes.

Stop and seek urgent medical care for:

• Leg pain, swelling, warmth, or redness (possible clot).
• Sudden chest pain, breathlessness, or coughing blood.
• Yellowing of the skin or eyes, or severe upper abdominal pain (possible liver problem).
• A severe headache, sudden vision changes, or weakness on one side of the body.

Safety essentials

• The combination with ethinylestradiol raises the risk of venous blood clots; know the warning signs (leg swelling, sudden breathlessness, chest pain) and seek care immediately if they occur.
• Cyproterone must not be used in pregnancy: it can interfere with the genital development of a male fetus.
• Smoking, prolonged immobility (such as long flights or bed rest), and a personal or family history of clots all add to the risk; tell your prescriber about any of these before starting.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.