Authors: Tomi Ruggles and Stephanie Sheahan.
Content Warning: This article contains reference to genitalia, sexual arousal (erections), fertility, and sexual health. When referring to specific parts of the body, we use anatomical/medical terms e.g., penis, testicles, nipples, sperm etc.
Note: Not all people want the same changes from using oestrogen, anti-androgens, and progesterone, and not all bodies will respond the same to hormone therapy. All the body changes described in this article are typical but not universal. You can watch some videos showing the diversity of individual experiences at the bottom of this post.
A trans woman with a hormone patch on her arm.
What is oestrogen?
Oestrogen, or estradiol, is a sex hormone that is produced naturally in our bodies, and in people who were born with ovaries it is the main sex hormone. Testosterone is produced by the testicles, so people born with testicles will tend to have a naturally higher level of testosterone, and it will be their main sex hormone.
Some, but not all, trans women and non-binary people presumed male at birth may choose to access hormone therapy to change the appearance and function of their body. When a trans woman or non-binary person speaks to their doctor about hormones, their doctor may prescribe them oestrogen hormones on their own, or with a testosterone blocking medication. When prescribed to affirm someone's gender, hormone therapy is referred to as gender-affirming hormone therapy or GAHT.
What are the options for oestrogen GAHT in Australia?
The most common type of oestrogen that is prescribed is pills (tablets), which are taken every day. Pills are favoured by many people as they are some of the easiest and cheapest hormones to access. However, pills need to be taken every day, and sometimes multiple pills in a day. Because of this, pills can be more disruptive of your day-to-day routine than other forms of GAHT. Oestrogen pills come under the brand names Zumenon, Progynova or Estrofem.
Gels and patches that are applied to the skin are another option. They might be safer for people who have liver problems or liver impairment, as the oestrogen passes through the skin into your body without being digested. Gel comes under the brand name Sandrena (sachets) or Estrogel (pump pack). Patches come under the brand names Climara or Estradot which are changed weekly or twice weekly. Some trans women and non-binary people prefer to use patches as they are applied less frequently, compared to gels which must be applied daily.
Implanted oestrogen is becoming an increasingly common option. Implants are a small stick or pellet of oestrogen that your doctor puts under your skin in a procedure with local anesthetic. Not all doctors have the equipment or skills to insert compounded implants. Trans women and non-binary people may choose implants as they only need an implant once or twice per year to maintain stable hormone levels. Implants are not on the Pharmaceutical Benefits Scheme (PBS) and must be sourced from compounding pharmacies at your expense. As they are made in compounding pharmacies, there is less quality control regarding the amount of oestrogen content, how it is metabolised or contamination and there may be risks.
Unlike in the USA and some other places overseas, injectable forms of oestrogen are rare in Australia and are not available on the PBS or listed in The Australian Informed Consent Standards of Care for Gender Affirming Hormone Therapy.
Oestrogen GAHT types and frequency of administration in Australia
Tablet Oestrogen:
Brand names: Zumenon, Progynova and Estrofem.
Frequency: Daily.
Percent of people: 62.9
Gel Oestrogen:
Brand names: Sandrena and Estrogel.
Frequency: Daily.
Percent of people: 10.0
Patch Oestrogen:
Brand names: Climara and Estradot.
Frequency: Weekly or twice weekly.
Percent of people: 17.1
Implant Oestrogen:
Made to order at compounding pharmacy.
Frequency: Every 6 – 24 months.
Percent of people: 15.9
The above information is sourced from the Australian Informed Consent Standards of Care for Gender Affirming Hormone Therapy and a recent survey of the Australian trans and gender-diverse community.
When you take hormone therapy, your doctor will monitor the levels of hormones in your body with blood tests. They will typically try to maintain your blood hormone levels in the same range as someone who was born with ovaries. On a blood test this will read as an oestrogen level between 250-1000 pmol/L and a testosterone level lower than 2 nmol/L but it does vary depending on the medications used. Some patients may prefer to have a testosterone level that remains higher.
While oestrogen dosages vary from person to person and should be discussed with your treating doctor, you can find recommended dosages on page 16 of The Australian Informed Consent Standards of Care for Gender Affirming Hormone Therapy.
What changes can I expect from oestrogen hormone therapy?
Taking oestrogen will change your body in many ways. It will make your skin softer, change where your fat is stored, and you will start to grow breasts. Hormone therapy may shrink your testicles and affect your erections. The list below explains in more detail what changes you can expect, but the main changes that happen are typically irreversible and cannot be undone. These permanent changes are testicle shrinkage, changes to your ability to make sperm, and the growth of your nipples and breasts.
These changes can affect how you feel about your body. Most people who choose to take oestrogen hormone therapy are happier, experience less depression related to their gender and body, and end up having a happier and more fulfilling life.
Oestrogen hormone therapy will not undo any lowering of the voice caused by a testosterone-driven puberty. If you are looking to change the sound of your voice you may consider personal voice training, assisted voice training, or vocal feminisation surgeries.
Common effects on the body when taking oestrogen GAHT and expected timelines for these changes
1-3 months:
Softening of skin.
Decrease in muscle mass and increase in body fat.
Redistribution of body fat to buttocks and hips.
Decreased sex drive.
Fewer spontaneous (random) or morning erections, decrease in erection firmness or ability to achieve erection.
Decreased ability to make sperm and semen (generally irreversible).
3 months - 2 years:
Growth of nipple and breast (irreversible).
Slowed growth of facial and body hair.
Slowed or ceased balding.
Decrease in testicular size (irreversible).
The above information is sourced from the Australian Informed Consent Standards of Care for Gender Affirming Hormone Therapy and Folx Health.
Will I also need to take an anti-androgen and progesterone?
Your doctor may prescribe you a testosterone-blocking drug (anti-androgen) to take with your oestrogen. This is to stop your body from making testosterone, and to stop the effects of the testosterone on your body. These medications come in pill form and are usually taken every day or every couple of days. two main types of testosterone blockers are Cyproterone and Spironolactone. Cyproterone is sold under the brand name Androcur, and Spironolactone under the brand names Spiractin and Aldactone.
About one in five trans people also take progesterone. This is another sex hormone, and it is found in higher levels in the blood of people born with ovaries predominantly to protect the uterus lining. There is not much scientific evidence for the use of progesterone with trans people yet, but studies are being done right now to investigate the effect of progesterone on breast growth, anxiety and even sleep. Progesterone is prescribed as a pill under the brand name Prometrium.
While anti-androgen and progesterone dosages vary from person to person and should be discussed with your treating doctor, you can find recommended dosages on page 16 of the Australian Informed Consent Standards of Care for Gender Affirming Hormone Therapy.
Do I need to take anti-androgens, or can I just take oestrogen?
Some people will not be prescribed testosterone blockers. This can be because they do not wish to stop the effect of testosterone on their body, they can't take them without feeling sick, or they simply do not need them. Some peoples' bodies will naturally stop making testosterone when they take oestrogen, and they will not need to take a testosterone blocker to achieve low testosterone levels. Some may only take testosterone blockers for a time, then find that less or none are needed. Others find that when they take testosterone blockers, their sex drive and sex life are impacted in a negative way.
Taking oestrogen without an anti-androgen is often referred to as ‘monotherapy’. Our research shows that one in four people taking oestrogen do not take an anti-androgen as well.
You can speak to your doctor about your body and what you want from hormone therapy when deciding what medications you will take.
What are the effects of anti-androgens?
The effect of anti-androgens on the body are primarily focused on the testicles, and facial and body hair. Anti-androgens will slow the production of testosterone in your body, shrinking your testicles. Within 3 months of starting anti-androgens, you will have lower levels of testosterone in your body, and you may have a decreased sex drive, or your sex drive may feel different. ‘Morning wood’ and random erections will stop happening, and you may have trouble getting or maintaining an erection.
Longer term, anti-androgens also change your hair. Baldness will stop progressing, however any baldness that you currently have cannot be reversed. Facial hair will grow slower, but as with baldness, any facial hair development that you already have cannot be reversed.
Are there any risks or adverse effects of GAHT?
Every medication comes with risks and effects that may or may not be unwanted. Oestrogen hormone therapy is no different.
Oestrogen therapy results in the reduction of testicle size as well as a reduction in the amount of sperm in semen and the ability of sperm to fertilize an egg. In general, taking oestrogen and anti-androgens reduces your fertility. This effect can be irreversible, continuing in some people even if hormones are no longer taken. Some people choose to store their sperm before starting hormone therapy, this is called fertility preservation. This involves giving a sperm sample, having your sample processed and then stored in a freezer until you want to use it. You can use stored sperm for artificial insemination or IVF. Sperm storage will come with additional costs to hormone therapy, as you will need to pay a storage facility to keep your sperm safe.
Taking oestrogen increases the body fat percentage and changes where fat is deposited. When taking oestrogen, less fat goes to your stomach and more to your hips, buttocks, and upper arms. This usually causes an overall weight gain, combined with a loss of muscle. This may be a concern to some people who have other weight or cardiovascular concerns. Your doctor can discuss your personal risk, and some trans people taking oestrogen may choose to change their diet and exercise in response.
Oestrogen can make the blood ‘stickier’, and because of this it raises the chance of developing a blood clot (also called or Deep Vein Thrombosis). Some people have a higher risk of developing blood clots, such as people over 45 years of age and those who have had clots previously. If you are at higher risk of blood clots, you will typically be prescribed patches, gels, or creams, as these forms of oestrogen are less likely to cause clots than pills.
Development of breasts in those on oestrogen also increases risk of breast cancer when compared to people assigned male at birth not taking these medications. You may need to get mammograms (breast cancer tests). These are usually done every two years between the ages of 50-74. Those with a family history of breast cancer may start testing earlier, after consultation with their doctor.
Testosterone blocking drugs have their own effects. Spironolactone is a diuretic, or ‘water pill’. It can make you need to pee more, and some people can find they get dizzy when standing up. It does this by changing the salt levels in your blood, which are called electrolytes. When taking Spironolactone your doctor will typically monitor your salt levels for any increases (called hyperkalemia) when you have blood tests.
It is important if you are taking anti androgens to also be taking enough oestrogen, as a lack of both oestrogen and testosterone in the body can cause a loss in bone density. Especially when beginning hormone medications, you should have regular blood tests to make sure that your medication provides a sufficient amount of hormones for bone health.
More information on the possible risks and side effects of oestrogen and anti-androgen hormone therapy, see page 254 of the World Professional Association of Transgender Health (WPATH) Standards of Care.
Oestrogen GAHT and wellbeing
The main thing to remember when taking oestrogen hormone therapy is to always follow your doctors' advice and talk to your doctor about your goals and how you are feeling about the changes caused by oestrogen. When GAHT is taken safely, most people experience a better quality of life. They are more satisfied with how they look, they feel happier, and this change in mood can improve all aspects of their life. It is common for people to make more friends, have better sex (if sexually active), feel more confident and just generally be more content with their lives after taking oestrogen hormone therapy.
Where can I find more Australia-specific information?
Transhub provides more Australia-specific information about oestrogen, by and for trans people. The Position Statement on the Hormonal Management of Trans and Gender Diverse Individuals published in the Medical Journal of Australia (2019) and the AusPATH Australian Informed Consent Standards of Care for Gender-Affirming Hormone Therapy (2022) may also be of interest.