Feminizing Hormone Therapy

Feminizing hormone therapy includes medications that will reduce the level of testosterone and increase estrogen (or estradiol) to allow feminizing changes to occur. It is important to let your provider know if you take any other prescribed medications or over-the-counter supplements as these may interfere with feminizing medications.

Testosterone blockers

Testosterone blockers may be started before estradiol, or at the same time. In the United States, the most common testosterone blocker is spironolactone. This oral medication may block the effects of testosterone and also reduce the levels in the blood stream. With these changes in testosterone, you may notice breast tenderness. The most common side effects include drop in blood pressure, increased urination and high potassium. Your provider will monitor your potassium levels. If this medication is not tolerated well, speak to your provider about alternatives.


Estradiol is a hormone that promotes feminine physical changes. Estradiol can be given in many ways, most commonly, oral, transdermal or injectable. Your provider should review the pros and cons of each of these. It is important to review your medical history with your provider particularly if you have a history of cancer (particularly breast or prostate), heart disease, stroke, blood clots, liver disease or you smoke, as your risks associated with hormone therapy may be increased if you have any of these. Risks related to estradiol therapy may include increased risk of blood clots, high triglycerides, high blood pressure and possibly heart disease/stroke, particularly if you are older than age 50 years.

Physical Changes

Physical changes may take some time to occur. Below we have provided a general expected timeline. It is important to know that everyone is different. Your height, voice and Adams apple will not change with hormone therapy.

In 1 to 3 months:
  • Decrease in sexual desire and function (including erections)
  • Baldness slows
In 3 to 6 months:
  • Softer skin
  • Decrease in testicular size
  • Breast development and tenderness
  • Change in body fat distribution
In 6 to 12 months:
  • Hair may become softer and finer

Fertility and Hormone Therapy

Feminizing hormones will decrease sperm production; however it is still possible to get your partner pregnant if you engage in vaginal sex. You may need to use additional birth control measures. If you wish to have children in the future, consider banking sperm before starting hormone therapy.

Follow-up Care

Your provider will recommend that you regularly come for follow up care after these hormones have started. Follow up visits may include physical examinations, measurement of hormone levels and sometime other testing depending on your age and medical problems. Other tests may include a bone density, mammogram, prostate assessment, sexually transmitted infection (STI) screen and follow up of blood sugar and cholesterol. If you are older than 50 years of age, your doctor may want to evaluate your risk of heart disease a little closer.

Used with permission of Mayo Foundation for Medical Education and Research
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