Male-to-female (MTF) hormone therapy, or estrogen hormone therapy, is a treatment that some people may receive in order to induce “feminine” physical traits and suppress “masculine” ones. This may involve taking estrogen in combination with anti-androgens.
People who undergo estrogen hormone therapy will receive medication to block the action of testosterone, a hormone responsible for traits that people may consider to be masculine.
They will also receive estrogen, which is the hormone responsible for what people may see as typically female characteristics.
There are several potential benefits and risks estrogen hormone therapy may have. The changes it causes may be temporary or permanent.
This article will replace the term MTF hormones with estrogen hormone therapy. This is because MTF terminology is binary and exclusionary. Not everyone who uses estrogen-based hormone therapy may identify as male or have the goal of becoming female.
In this article, we discuss estrogen hormone therapy, including what people can expect during and after treatment.
Estrogen hormone therapy is a treatment that
People undergoing estrogen hormone therapy usually receive the hormone estrogen, and other medication to reduce testosterone.
This can result in the development of typically feminine secondary sexual characteristics, such as fat distribution and development of breasts. It can also decrease the growth of facial and body hair.
Other names for estrogen hormone therapy may include feminizing hormone therapy, gender affirming hormone therapy, and cross-sex hormone therapy.
A person may undergo estrogen therapy if they have gender dysphoria. This is when a person experiences distress because their gender identity does not match their sex assigned at birth.
Estrogen treatment
Those who receive estrogen hormone therapy during adolescence (around the age of 16 years or older) may avoid the development of male secondary sexual characteristics, such as a deepening voice and the growth of body hair.
Not everyone who experiences gender dysphoria will undergo hormone therapy. While it may have benefits for some, the treatment is not without risk.
According to the National Transgender Discrimination Survey Report on Health and Health Care, at least
However, estrogen hormone therapy may not be suitable for everyone. Some people may experience potential complications or difficulties in receiving treatment. This may include those who:
- are under 16 years of age
- smoke
- have serious mental health issues that require treatment
- have or have had a hormone-sensitive cancer, such as breast cancer, prostate cancer, or pituitary cancer
- have a thromboembolic condition, such as deep vein thrombosis
The standard first-choice gender-affirming hormone treatment for those receiving estrogen hormone therapy involves estrogen in combination with anti-androgens.
A doctor may also monitor health to ensure the body is absorbing medication and to help identify potential health problems.
Estrogen hormone therapy may involve:
Estrogen
Estrogen is responsible for most feminine characteristics. The
Estrogen hormone therapy is available as an injection into a muscle (intramuscular) or a pill. It is also available in transdermal form, as a patch that a person wears on their skin.
Those aged
Anti-androgens
People can take anti-androgens as either injections under the skin (subcutaneous) or oral medication.
Anti-androgens block the action of testosterone to reduce masculine characteristics. The most common oral anti-androgens used in the United States are spironolactone and finasteride.
Progesterone
Some people undergoing estrogen hormone therapy may also receive progesterone.
However, using this hormone is controversial, and many guidelines do not recommend its use. As a result, many doctors do not prescribe it.
When can people take it?
The age at which people can access gender affirming hormone therapy varies globally.
For example, in Europe, many countries allow people aged 14–18 to access it. However, in some countries, such as the Netherlands, people can access it from the age of 12 years with parental consent.
In some other European countries, access depends on the maturity of the person who would like to receive the therapy.
In the U.S., most people can access estrogen hormone therapy at the age of 18 years, when they are capable of consent. At 17 years old, a person may have access, but they will require a parent or guardian to accompany them to appointments. At the age of 16 years or younger, additional paperwork is necessary to access such therapy.
Some people may consider estrogen hormone therapy a second puberty. While some changes may occur within weeks, it can take years for the full effect.
Changes may include:
Physical changes
People using estrogen and anti-androgens as part of their hormone treatment may notice:
- drier and thinner skin with smaller pores
- changes in the odors of sweat and urine
- a reduction in sweat production
- the development of breast buds beneath the nipples that will develop into breasts as treatment progresses
- a more feminine facial appearance
- an increase in fat around the hips and thighs
- a loss of muscle mass in the arms and legs
- a reduction in strength
- a reduction in body and facial hair
These changes could potentially affect a person’s verbal and spatial abilities and the way they interact with others.
Reproductive changes
According to UCSF Transgender Care, the impact of estrogen hormone therapy on fertility is unclear.
Individuals who are sexually active with a person who can get pregnant should use condoms or another form of birth control to prevent unplanned pregnancy.
However, those who may wish to be a parent at some point in the future should consider whether they want to preserve their sperm. While fertility may return after stopping hormone treatment, this does not always happen.
Emotional changes
During estrogen hormone therapy, a person’s emotional state may or may not change. A person is likely to experience a rollercoaster of emotions, but this will usually settle down after a while.
People may experience a wider range of emotions, have different interests, or behave slightly differently.
When a person receives treatment for gender dysphoria, they may also begin to feel more like themselves and more comfortable in their own body.
Sexual changes
Estrogen hormone therapy will typically change a person’s libido and their genitals. Individuals may experience:
- a reduction in the number, duration, and firmness of erections
- shrinking of the testicles to less than half their original size
- changes in orgasms
- changes in arousal
- changes in sexual interests and attractions
For some, the primary benefit of estrogen hormone therapy is a
It may also enable a person to experience gender congruence, which can feel empowering and liberating.
Moreover, a
Estrogen hormone therapy can also involve a number of risks, including:
- Fertility changes: This type of hormone therapy can reduce fertility. Before undergoing treatment, people should consider whether they wish to preserve their sperm in order to conceive a child in the future.
- Libido changes: Estrogen can reduce a person’s libido, erectile function, and ejaculation. Medications such as sildenafil (Viagra) and tadalafil (Cialis) may improve a person’s ability to have an erection.
Other complications of estrogen hormone therapy include:
- blood clots, which can result in stroke or be fatal
- cardiovascular disease
- worsening of anxiety, depression, or other mental health conditions
- worsening of migraines
- gallbladder or liver disease
- high cholesterol and triglycerides
- high blood pressure
- type 2 diabetes
- weight gain
While some results are reversible after a person stops treatment, others are not. Some of the irreversible effects include breast growth and changes in fertility.
Before a person begins estrogen hormone therapy, a doctor will evaluate their health. They may:
- take a complete medical and family history
- perform a physical examination
- order blood tests
- request relevant age- and sex-related screenings
Doctors will also inform the person about the potential risks of the treatment and discuss contraception and future fertility, including the freezing of sperm.
Some people may also undergo a mental health evaluation that explores their mental health, gender dysphoria, and use of alcohol and drugs.
People under 18 years of age may also need to see doctors with expertise in pediatric transgender health.
Some individuals may wish to further prepare by seeing a mental health professional before beginning treatment to explore their goals and expectations of hormone therapy, as well as its side effects and challenges and ways to deal with them.
People may also want to discuss the available social supports.
During the visits, in addition to taking estrogen, a person will take an anti-androgen to block testosterone and its effects. Some people may also take other medications, including progesterone.
A few weeks after starting the medication, a person may begin to notice physical effects, such as a decreased libido. Other changes — including altered facial appearance, fat distribution, and genitals — may not occur for several months or years.
People will have regular checkups with a doctor during hormone therapy in order to monitor the progress of the treatment and check for adverse effects.
Doctors will also recommend screenings, such as bone mineral density and breast cancer and prostate cancer screenings, based on age-appropriate recommendations.
The results of hormone therapy can vary and will depend on factors such as genetics, overall health, and the age of the person undergoing treatment.
People who begin treatment in their 40s or 50s can expect less dramatic changes than adolescents or young adults undergoing estrogen hormone therapy.
Breast development in people who begin treatment after puberty, for example, will be modest. Some individuals may wish to undergo a breast augmentation surgery once they have been on hormone therapy for 1 year or more.
Once a person is within the normal range of estrogen and testosterone levels, taking higher doses does not tend to bring about more dramatic results. However, higher doses may lead to complications.
Estrogen hormone therapy is a treatment option for people with gender dysphoria. It causes the development of typically feminine traits, such as breast tissue, decreased muscle mass, and a reduction in facial and body hair.
People with gender dysphoria who undergo this treatment may experience an improvement in mood and quality of life. However, the treatment carries a number of risks, including a loss of fertility and increased likelihood of blood clots and high blood pressure.
Results will vary depending on several factors, including when a person begins treatment. People who would like to know more about estrogen hormone therapy can consult a doctor.