Feminising Hormone Therapy (MTF): Steps, Medicines and Safe Monitoring

Many trans women who come to see me started hormones as teenagers with contraceptive pills a friend recommended. Some took several pills a day because they wanted their breasts to "come in faster"; some took high-dose anti-androgens for ten years or more. What I want you to know is that today we have far safer regimens, and beautiful changes don't have to cost you your health.

How do feminising hormones work?

Feminising hormone therapy has two goals at the same time:

1. Increase the female hormone estradiol, which causes breast growth, softer skin and a female pattern of fat distribution.
2. Reduce the effects of male hormones, both through estradiol itself, which suppresses testosterone production, and through an anti-androgen in some people, which helps reduce body hair, oily skin and spontaneous erections.

See the timeline of what changes when in when do changes happen on feminising hormones?

Raise estradiol

Main medicine

• Breast growth
• Softer skin
• Female fat distribution

Reduce male hormone effects

By estradiol itself, plus blockers in some

• Less body hair
• Less oily skin
• Fewer spontaneous erections

How to start

1. Consultation and assessment. Talk about your goals, expectations, physical and mental health, fertility (consider sperm banking before starting) and things that can't be reversed, such as breast growth.
2. Physical examination and blood tests. Blood pressure, weight, liver, kidneys, lipids, glucose, electrolytes and baseline hormones. See the list in blood tests before starting gender-affirming hormones.
3. Choose a regimen together, based on risks, convenience and budget.
4. Follow-up about every 3 months in the first year, adjusting the dose based on blood results and the actual changes you're seeing.

Commonly used medicines

Estradiol: the main medicine

• Tablets, such as estradiol valerate or estradiol hemihydrate, are easy to use and easy to find, but they pass through the liver first, so they affect blood clotting more than transdermal forms.
• Gel or patches don't pass directly through the liver, so they suit people who are older, smoke or have a risk of blood clots.
• Intramuscular injections are given in cycles, and hormone levels rise and fall with each dose.

For a detailed comparison of each form, see trans women's hormone regimens: tablets, gels and injections.

Anti-androgens

• Cyproterone acetate suppresses male hormones effectively and is widely used in Thailand. However, in 2020 the European Medicines Agency (EMA) warned that long-term use of doses of 10 mg/day or more increases the risk of meningioma (a usually benign brain-lining tumour), in proportion to the cumulative dose. Studies in trans women have found that a low dose of about 10 mg/day suppresses testosterone almost as well as higher doses when combined with estradiol. Current practice is therefore to use the lowest effective dose and to consider reducing or stopping it when no longer needed, for example after orchiectomy.
• Spironolactone is a diuretic with anti-androgen effects. Potassium and kidney function need monitoring, and it may cause frequent urination and low blood pressure.
• GnRH agonists, such as leuprorelin or triptorelin, switch off hormone production at its source. They work well with few side effects but cost more.

Cyproterone acetate

• Suppresses male hormone well; widely used in Thailand
• Cumulative high doses risk meningioma
• Use the lowest effective dose (EMA 2020)

Spironolactone

• A diuretic that blocks male hormone effects
• Needs potassium and kidney monitoring
• May cause frequent urination, low blood pressure

GnRH agonist

• Suppresses hormone production at the source
• Works well, few side effects
• Higher cost

Medicine and dose are as assessed by your doctor together with blood results.

Other medicines you may hear about

• Finasteride or dutasteride reduce the conversion of testosterone to DHT and may help with hair thinning in some people, but they are not core medicines (see finasteride in trans women).
• Progesterone. Some people believe it improves breast shape, but WPATH SOC-8 states that the evidence is insufficient. If you want to use it, discuss the benefits and risks with your doctor first.

Monitoring and blood targets

• Estradiol is generally targeted at around 100–200 pg/mL.
• Testosterone below 50 ng/dL.
• Liver values, lipids, glucose and potassium (if using spironolactone) are checked on schedule.
• Some guidelines recommend checking prolactin, especially in people using cyproterone acetate.
• In the long term, breast cancer screening should follow the usual schedule after long-term hormone use, and prostate health still needs attention with age.

Side effects and warning signs

Possible effects include breast tenderness, mood swings early on, reduced sex drive, fewer erections and weight gain. If this is affecting your relationship, read low sexual desire.

Go to hospital urgently (call 1669, Thailand's medical emergency number) if you have:

• Swelling and pain in one leg, chest pain or sudden breathlessness
• An unusually severe headache, blurred vision, or weakness in an arm or leg
• Yellowing of the skin or eyes
• A persistent headache with changes in vision or memory, if you have used cyproterone acetate long term

Starting safely with Dr. Kris Clinic

At Dr. Kris Clinic, I care for feminising hormone therapy from the first consultation and blood tests to an individually planned regimen and dose adjustments based on your real results, including for people who have used hormones on their own and want to switch to a safer regimen. All medicines are registered and are dispensed only after a doctor's assessment. Consultations are available in Surat Thani and online, in English if you prefer. For the full overview, read gender-affirming hormone therapy (GAHT).