Testosterone Blockers

Testosterone blockers, also called antiandrogens, are medications that reduce the effects of testosterone in the body. Depending on the substance, they may suppress testosterone production, block androgen receptors, or influence hormonal feedback systems. They can be used, among other indications, by transfeminine and AMAB non-binary people as part of a medical transition, often within feminizing hormone therapy.

They are commonly combined with estrogens so that the desired hormonal effects can be achieved without using unnecessarily high estrogen doses. Not everyone needs testosterone blockers; the type, dosage, and duration depend on a person’s health, goals, blood test results, and the specific medication used. Possible side effects vary by drug and may include fatigue, changes in blood pressure, changes in libido or mood, electrolyte disturbances, liver strain, or effects on fertility and sexual function.

Testosterone blockers should only be taken under medical supervision. Long-term, strong suppression of testosterone without sufficient other sex hormones, such as estrogen, can increase health risks such as loss of bone density and other hormone-related problems. Regular blood tests and qualified adjustment of treatment are therefore important; self-directed stopping, combining, or dosing is not recommended.