Hormones are chemicals that all humans make to regulate how the body works. They have effects on all aspects of a person’s life and health, including physical, emotional, and social health. 

In gender healthcare, the two hormones we talk about most are testosterone and oestrogen. Everyone, no matter what gender they are, or if they have gone through a hormonal transition or not, make both testosterone and oestrogen.

Testosterone and oestrogen are sometimes referred to as ‘sex hormones’ or ‘sex steroids’. This is because their primary functions are related to the development of sexual characteristics such as body and facial hair growth, breast development, and genital changes.

Oestrogen and testosterone also have major effects on sex drive and sexual and reproductive function (that is, the ability to have sex and to have children). Changes in these hormones may affect the ability to have sex and the ability to have children.   

That depends on your gender affirming goals. Everyone has an individual point of view, and gender affirming goals vary significantly from person to person. Many trans people do not use hormones, because they are satisfied with how they affirm their gender personally or socially.

Some trans people use testosterone. Some trans people use oestrogen. Some trans people use testosterone or oestrogen with a medicine called a blocker.

A blocker is a medicine that suppresses the levels of testosterone or oestrogen in the body.  Some people use a blocker on it’s own for a while. While it is ok to be on blockers on their own for a while, it is not recommended to be on blockers on their own in the long-term, as this may have significant negative health effects.  

Some people start on one type of hormone treatment, and then change to another as time goes on. Some people start on hormone treatment and later decide to stop using hormones.

Given that there are many options, the best thing to do is to speak to your doctor about your options. We can talk about this during your initial assessment with us. We can continue this conversation for the duration of your time with us, and start, stop, and change hormone treatment as needed to meet your gender affirming goals.

In Ireland, there are three main forms of oestrogen available on prescription: patches, tablets and gels. Patches give good levels of oestrogen with a low risk of medical complications. Patches are placed on the skin and are worn continuously for three days before changing.

Tablets are taken once or twice daily, and give good levels of oestrogen. It should be noted that tablets have a higher risk of medical complications as compared to patches or gels. For more on complications, see complications question listed below.

Gels give good levels of oestrogen with a low risk of medical complications. Gels need to be applied daily on the skin. Injectable oestrogen is not available in Ireland. It is possible to change between gels, tablets and patches. If you would like to discuss changes in your oestrogen therapy then please discuss with your prescriber.

Changes vary from person to person. Some people want to take things slowly, and some people would rather see lots of changes happen very quickly.  How much change happens, and how quickly it happens, is down to a combination of a number of factors. It is important to remember that the extent of change, and rate at which the changes take place, is often largely dependent on genetic and physical factors.

Hormonal transition is like puberty. For some people, the changes of puberty happen over a very short time. For others, it takes years for the full effects to be seen.

This is like how in some families, the women have large breasts, and in other families, the women have small breasts. All of these women could have the same levels of oestrogen, but because of genetic differences, will have different physical changes.  

While it is possible to make adjustments in hormone doses to see if this will help achieve certain gender affirming goals, it can be that despite changes in doses, we do not achieve the desired effects.

In terms of changes in general, the following may occur (as outlined above, everyone will have a different experience of transition and therefore these effects may not occur in some people)

Physical changes may include:

Skin:

• Skin changes usually begin within three months of oestrogen use.
• Skin may become drier and thinner, with smaller pores and less oil production.
• Skin may feel softer.
• There may be a subtle change in sensation or body odour. 

Breast development:

• Breast development will usually begin within the first six months of oestrogen use, but can take up to two years or more before breast development is complete.
• Within a few weeks small “buds” or “bumps” may be felt under your nipples.
• These may be slightly tender or sore to the touch:- this is normal breast development and the tenderness should ease as the months go by.
• It is not unusual for breast growth to become more obvious on one side before the other – usually things balance out as time goes on. 

Muscle and fat changes:

• These changes can take years to become fully obvious.
• Your body fat will begin to redistribute, so that you might notice more fat on your belly or buttocks.
• Muscles will usually become smaller so you will potentially notice less muscle in your arms and legs.
• The extent to which you gain or lose fat and muscle on oestrogen will depend on your genetics, diet, lifestyle, and baseline muscle mass.

Body and facial hair:

• The effect of hormones on hair growth will usually start within three months but may take a year or two to become fully obvious.
• Body hair, including hair on the chest, back and arms, will decrease in thickness and grow at a slower rate, but it will likely not go away completely.
• Facial hair may thin a bit and grow slower but it will rarely go away entirely without electrolysis or laser treatments.
• Hair loss (balding) will usually stop on hormones, but hair that has been lost will not be expected to grow back.

Changes in mood:

• Low mood is common in the first few months following the start of your hormonal transition.
• If your mood becomes very low, or you are worried about it, then please talk to us or contact your GP for advice.

Decrease in sex drive:

• This is more obvious for people on blockers.
• A decrease in the ability to achieve or maintain an erection will be noticed within three months of starting blockers.
• Changes in the ability to experience orgasm are expected: it may become very difficult to orgasm at all.
• A reduced ability to ejaculate, or noticeably smaller volume of ejaculate is expected.
• Significant reduction in fertility is expected (see below).

Gradual reduction in size of testicles:

• This effect may or may not be noticeable, and if it does become noticeable then it can take several years to become apparent.
• The amount of scrotal skin will not change, but the scrotal skin may become more loose as time goes on.

Changes will not be expected to include:

• Changes to the bone structure of the face.
• Changes to the size of hands or feet.
• Changes to voice pitch or character.

Not everyone wants or needs to use blockers.

The main effect of blockers is to reduce levels of testosterone. Therefore, most people who use blockers use them to reduce the amount of testosterone in their bloodstream. 

Sometimes blockers are used to reduce oestrogen levels as well. This might be needed in people who continue to have vaginal bleeding or certain gynaecological symptoms after starting testosterone. 

 The types of blockers include:

• Goserelin (injection)
• Triptorelin (injection)
• Leuprorelin (injection)
• Spironolactone (tablet)
• Finasteride (tablet)
• Cyproterone (tablet)
• Bicalutamide (tablet)

At the National Gender Service, the most commonly prescribed blocker is Goserelin (Zoladex). However, all of the options listed above are available.

The choice of blocker depends on gender affirming goals, preference for tablets or injections, and a person’s medical history.  

Some people want to try progesterone to see if it gives them any additional benefits. Prescriptions for progesterone can be issued, but only with the understanding that there are no proven benefits of progesterone therapy, and there is a significantly increased risk of medical complications and harm.

A common reason for seeking a trial of progesterone is enhancement of breast growth. It is recommended that you allow your natural breast growth to finish before considering a trial of progesterone. Additionally, there is no evidence that progesterone prevents or reverses baldness in those prone to it. 

There are two main forms of testosterone available on prescription in Ireland: gels and injections.

Gels give good levels of testosterone and allow day by day control of dosing. This is most useful at the start of transition when the risk of side-effects or adverse events is higher. Therefore, the preferred approach in the National Gender Service is to use gels when starting a testosterone transition, so that the person has the ability to change doses, or hold off on doses, on a day by day basis. Gels need to be applied daily on the skin.

Injections give good levels of testosterone and are given as injections into the muscle every few weeks or months, depending on the type you use. The two types available in Ireland are testosterone undecanoate (e.g. Nebido) and testosterone esters (e.g. Sustanon). Other injectable forms of testosterone are not currently available in Ireland.

Both gels and injectable testosterones give you the same effects and have the same risks of complications. When doses and blood test results are within recommended limits, physical health complications like heart attack, stroke and liver disease are very uncommon.

It is possible to change from gels to injections, and from injections to gels. If you would like to discuss changes in your testosterone therapy then please discuss with your prescriber.

Changes vary from person to person. Some people want to take things slowly, and some people would rather see lots of changes happen very quickly.  How much change happens, and how quickly it happens, is down to a combination of a number of factors. It is important to remember that the extent of change, and rate at which the changes take place, is often largely dependent on genetic and physical factors. 

Hormonal transition is like puberty. For some people, the changes of puberty happen over a very short time. For others, it takes years for the full effects to be seen.

This is like how in some families, the men all have beards or become bald, and in other families, none of the men can grow a beard but they all have full heads of hair. All of these men could have the same levels of testosterone, but because of genetic differences, they will have different physical changes.  

While it is possible to make adjustments in hormone doses to see if this will help achieve certain gender affirming goals, it can be that despite changes in doses, we do not achieve the desired effects.

In terms of changes in general, the following may occur (but also may not)

The first physical changes you will probably notice are:

• Skin will become more oily and pores will become larger.
• Body odour may change and you may notice that you sweat more easily than before.
• You may develop acne, which in some cases can be severe, but usually improves with time and standard acne treatments.
• Body muscle and fat changes are gradual, and usually take a number of years to stabilise.
• Your muscle mass and strength will increase, although this process will take years to complete. The extent of muscle development will depend on a variety of factors including genetics, diet and exercise.
• Thickening of the vocal chords, which will result in a more male-sounding voice.
• The hair on your body, including your chest, back and arms will increase in thickness and will grow at a faster rate.
• Hair loss may occur depending on your genetic potential for hair loss. You may expect to develop hair loss in a similar pattern, and at a similar age, to other men in your family.
• Facial hair development varies from person to person, and similar to hair loss, can be expected to occur in a similar pattern to other men in your family.
• Changes in mood: mood may be lower for the first few months of your hormonal transition. You may also experience an increase in anxiety, and you may feel more prone to anger or become more irritable for the first few months of your transition. These effects usually lessen as time goes on.
• Periods will stop and should be expected to stop completely between 6 and 12 months of testosterone therapy.
• Testosterone will result in enlargement of the clitoris, and in increased sensitivity of the clitoris.

Changes will not be expected to include:

• Reduction in the size of the breasts.
• Changes to the size of hands or feet.
• Changes to the bone structure of the face. 

Soon after beginning testosterone, you will likely notice a change in your sex drive, and your genitals, especially your clitoris, will begin to change. 

The clitoris will enlarge and will become larger when you are aroused. You may find that your orgasms will feel different, with perhaps more intensity. At the onset of your transition, the sensitivity in your clitoris may feel like pain. If this happens, then it usually becomes less painful over time. However, if you are worried about any of these changes then let us know and we can talk to you about it. 

As your sex drive changes, you may find that sexual interests, attractions, or orientation may appear to change. It is good to explore these new feelings, but it is important to do that safely. If you have a regular sexual partner or partners, then it is advisable to have a conversation with them prior to starting hormones, to make them aware of potential changes in your shared sexual lives.

Do remember that testosterone is not a contraceptive, and so if you are having sex that could result in pregnancy, and you do not want to become pregnant, then you should ensure that you are using an effective contraceptive. 

Trans men and people using testosterone may use any form of contraception apart from those containing oestrogen. There are numerous options available that do not contain estrogen, including daily tablets and long-acting options (implants that go under the skin, and coils that are inserted via the vagina).  Trans men and people using testosterone may also use emergency contraception, also known as the “morning after pill”. Ask your healthcare provider for more information on the contraceptive and family planning options available to you.

If you suspect you may have become pregnant, or have a positive pregnancy test while taking testosterone, speak with your prescriber or healthcare provider as soon as possible, as testosterone can cause serious fetal malformations.

Periods will become lighter and/or more irregular in the first few months, before stopping altogether. There may be heavier or longer lasting periods for a few cycles before they stop altogether. Sometimes, ongoing bleeding is a sign of too much or too little testosterone.  If you continue to have bleeding after six months of continuous testosterone therapy, then please talk to your prescriber, as a dose adjustment may be needed.

It’s also important to know that, depending on how long you’ve been on testosterone therapy your fertility may be affected. 

If future fertility might be important to you, then discuss your options with your hormone prescriber. Egg freezing is not a guaranteed method of preserving your fertility. Frozen eggs do not last as well as frozen sperm, and so may not last for a long time. If you have a partner who can produce sperm, and you would both like to freeze embryos, then this might be a possibility. Frozen embryos will last for a longer period of time than eggs. If you would like to consider your fertility preservation options then let us know and we can talk about them.

When you are on hormones, either testosterone or oestrogen, you should have regular blood tests.

For advice on getting your bloods checked when taking testosterone click here.

For advice on getting your bloods checked when taking oestrogen click here.

In the first couple of years after starting hormones, these should be checked every three or six months. After that, the blood tests should be checked at least once a year.

 The blood tests needed are:

• Full blood count
• Liver function tests
• Renal function
• Lipid profiles
• Testosterone
• Oestrogen
• Gonadotrophins (FSH, LH)
• Prolactin (only needed in people using oestrogen)

If you are attending the National Gender Service, and would like to have your blood tests done with us, then let us know and we can send out the required blood forms. Blood tests at the National Gender Service are free of charge but you do need to attend St Columcille’s Hospital to have the blood tests taken. 

If you do not want to, or cannot, attend the National Gender Service for your blood tests then please talk to your GP about having these blood tests done locally. 

The rate and risk of complications depends on your medical history, and an individual risk assessment is part of your Endocrine Clinic appointment with us at the National Gender Service. 

While there are a wide range of potential physical health complications associated with hormones, the most important ones to know about are:

Clots: If you are on oestrogen or testosterone, then there is an increased risk of clots. This can result in:

• Clots in the legs (this is called DVT). 
• Stroke.
• Clots in the lungs (this is called Pulmonary Embolism). 
• Heart attack.

Liver damage: hormone therapy can damage the liver, especially if you already have liver disease, or if your hormone doses are higher than usual.

Most people are at low risk of these complications, but this can change over time. Your risk of complications should be monitored by your prescriber, and therapy reviewed as needed to reduce the risk of complications to a safe level. If you are worried about your risk of complications, then please talk to your prescriber. 

There are also some expected effects of hormones that are not complications as such, but which can be uncomfortable. These include:

Hair loss:

• Some people on testosterone will develop irreversible hair loss. This is not a complication of therapy but is simply a normal biological effect of testosterone in people who have a genetic tendency to hair loss.
• Changes in testosterone dose or use of treatments like minoxidil or finasteride might be helpful.
• If you are worried about this then talk to your prescriber.

Acne:

• For people at the start of their hormonal transition, and for many people on testosterone, acne develops.
• This will usually resolve without specific treatment, but if you are worried then please talk to your prescriber.

Changes in sex drive and sexual function:

• Hormone treatment will affect your sex drive and sexual function.
• If any of these effects are uncomfortable or unwanted then please talk to your prescriber.

It should be noted that the overall risk of complications or adverse events for people using hormones is low once a comprehensive assessment has been completed prior to initiation of hormone therapy. If you are worried about any complications or effects of hormones, or about the need for extra monitoring of your health and well-being, then please talk to your prescriber.

This depends on what other medications you are taking. Please let your prescriber know if you are on any medication, or if your medication changes.

Almost all medication is safe to take with hormone therapy, but in some specific cases, there can be dangerous interactions between medicines and hormones. If in doubt, then please talk to your prescriber.

Changes vary from person to person. It is completely normal for you to have a different experience on hormones than other people. This is the case even if you are on the same hormones as other people. 

Sometimes, physical changes do not happen because your hormone dose is too low or too high. Therefore, if you are worried about your experience on hormones then the first thing to do is talk to us. As a first step, we will likely recommend blood tests to ensure that your hormones are at the appropriate levels.

If your hormones are at the right levels, then it may be that your body has changed as much as it will on hormones. Much of the change that people get on hormones is due to genetics (for example the way that you and other people in your family are made: some families have more facial hair or bigger breasts than others). Some of the change is due to nutrition and physical health. It is important to have a healthy balanced diet, and to have any co-existing health conditions managed appropriately.

Not seeing the physical changes that you were expecting can be very disappointing. If your mood is affected by this, then please talk to us and we can talk about this.

Everyone has a different experience of their hormonal transition. Many people notice that mood and general well-being improve after starting hormones. However, low mood and negative symptoms are also common in the first year after starting your transition. This can be due to the changes in hormone levels in the bloodstream. Changes in hormone levels –  especially rapid changes in levels, can adversely affect mood.

Many people report feeling more sad or more anxious within that first year of transition, and for most people these mood symptoms improve as time goes on. However, if you are suffering from uncomfortable mood symptoms or anxiety then do please talk to us, or your GP, about support or treatment options.  

Some people want to use very small amounts of hormones. This is sometimes called micro-dosing. This is perfectly safe to do for most people, but if you are on blockers or if you have had a hysterectomy or genital surgery, then micro-dosing might not be safe. If you would like to micro-dose then let us know and we can talk through your options. 

After starting hormones, many people stay on them for life. Some people stay on them for a while and then stop them. Some people stop and start hormones over the course of their life.

Taking a break from hormones is ok. It is recommended that you talk to your prescriber before stopping hormones just in case there could be any negative health effects.

It is essential to speak to your prescriber about taking a break from hormones if you have had bottom surgery or hysterectomy, or if you are continuing to take a blocker. In these scenarios, there could be serious health problems as a result of stopping hormones.

It is important to know that if you are taking blockers without oestrogen or testosterone for a long time this could cause serious health problems. Stopping blockers is usually easy to do, as long as you are informed about the effects. As with hormones, please talk to your prescriber before stopping your blocker.

If you would like to take a break from hormones, the please talk to your prescriber before making any changes.

The first step is to ask your GP to refer you to us. Once we receive the referral then we can take the next steps. We can accept referrals from any doctor registered with the Irish Medical Council, so if you are seeing a doctor who is not your GP then they can also refer to us. However, we recommend that your usual GP is copied into that referral as ultimately you will be discharged back to your GP for ongoing care. See our Referral section for advice for you GP or referrer.

You can ask your current prescriber to refer you to us. See our Referral section for advice for your referrer.

The first step is to ask your GP to refer you to us. Once we receive the referral then we can take the next steps. See our Referral section for advice for your GP or referrer.

As we can only accept referrals for people resident in Ireland and from doctors registered with the Irish Medical Council (the regulatory body for doctors in Ireland), we cannot accept a referral for your care yet.

For now, we recommend the following:

• Source any documents from any healthcare professional involved in your transition to date, and bring a copy of these documents with you to Ireland.
• When you arrive, register with a local GP or with your Student Health Service.
• Ask your GP or Student Health Doctor to refer you to our Service.
• Ensure that they have a copy of the documents from your previous healthcare providers, and that they send us a copy for review with your referral.
• Bring as much HRT with you as you can (or other medications you may be on) and discuss ongoing treatment options with your current provider to see if they can offer bridging prescriptions for you while you are waiting for an appointment with us.