Resources ・ Hormone Therapy

A handbook to estrogen & androgen blockers

Foria's clinical team

by Foria Clinical Team

minute read

What are estrogen and androgen blockers? Learn about medication types, effects, timelines, things to keep in mind, and how to get started.

On this page

    Share article

    Share on FacebookShare on Twitter

    If you’re looking for information about estrogen, you’re in the right place. Maybe you’re deciding if hormones are right for you, or perhaps you’re already on treatment. Either way, we’re here to help! This article will run through how feminizing hormones work, the types available and changes you can expect from treatment.

    What are estrogen and androgen blockers?

    Estrogen is a hormone and androgen blockers suppress your body's natural testosterone. They are taken by people who were assigned male at birth, and can also be taken by intersex people. These medications have feminizing effects, and a treatment regimen usually consists of both. Androgen blockers suppress your body’s natural testosterone and estrogen is a hormone. If you’ve had bottom surgery then you won’t need to take androgen blockers. This is because testosterone is mostly produced in the testicles, which are removed during surgery.

    These medications produce changes to your body that can better reflect your gender identity and/or expression. Changes include breast growth, softer skin and changes to your body fat. They also have psychological effects - they can change your sex drive and mood.

    Medication types

    If you’re interested in starting hormones, you have some choices when it comes to medication. Androgen blockers come as pills you take every day, but there are multiple options for estrogen. The first is oral estrogen, which you take as daily pills. The second is topical estrogen, which you apply as a patch twice a week. The third is an injection which is taken once or twice a week, which you administer yourself. You can also have someone else do the injection for you.

    Androgen blockers

    Androgen blockers are medications that suppress your body’s natural testosterone. They’re sometimes just called “blockers” (although they aren’t the same as puberty blockers, which are prescribed to trans youth). If you’ve had bottom surgery you won’t need them.

    There are two medications that are commonly used as androgen blockers: spironolactone (sometimes called “spiro”) and cyproterone. Your clinician can talk you through the benefits and side effects of each one to help decide what’s best for you.

    Androgen blockers are covered by public drug programs in Ontario, if you qualify. They are also covered in Alberta (if you qualify), but you will need to submit paperwork for cyproterone.

    Oral estrogen

    Oral estrogen is available as pills you take every day. The benefit of this option is that it’s cheaper and covered by public drug programs in Ontario and Alberta, if you qualify. The drawbacks are that it can have more health side effects, because it gets processed by your liver. Your body also absorbs less of the drug this way.

    Topical estrogen (patches)

    Another option is topical estrogen, which is available as a patch you put on your skin. These stay on your skin for 3-4 days (you can use one or more patches at a time, depending on your dose). Topical estrogen can be more expensive than pills but it has a lower risk of health side effects. This is because it gets delivered directly into your bloodstream and skips your liver. It is covered by public drug plans in Alberta (if you qualify) but not in Ontario.

    Applying estrogen patches

    1. Choose your area. The best places to apply estrogen patches are where they won’t rub against your waistband and where your skin doesn’t bend or move much. Your stomach, back and buttock are best. Body parts like elbows, armpits or behind your knees won’t work. Do not apply patches to your breast or genital area.

    2. Clean and dry. Make sure your skin is clean and dry before applying. If you apply after a shower, you need to dry off completely. Don’t apply the patch to irritated, very hairy or freshly shaved skin.

    3. Apply! Tear open the pouch (don’t cut it with scissors), remove the patch and peel off the plastic backing. Place it on your skin, pressing firmly to make sure it sticks.

    4. Keep an eye on it. You can shower, swim and work out with patches, but sometimes they can come off. A long time underwater and in direct sunlight can make this more likely. If a patch comes off then try to re-stick it in a new area. If that doesn’t work, you can replace it.

    5. Rotate. Patches can sometimes irritate your skin, so try to rotate body parts to give your skin a break. Wait a week after removing a patch before applying it to that area again.

    Injectable estrogen

    Injectable estrogen is taken once or twice a week and you can administer it yourself. One benefit is that it’s cheaper than topical estrogen if you’re paying out of pocket. It’s also less demanding on your schedule than daily topical applications. A drawback is that you have less control over your dose, because you are taking larger amounts less frequently. Also, some people don’t like handling needles. You can get someone else, like a loved one or a healthcare professional, to do your injections if you’d prefer.

    Effects of estrogen and androgen blockers

    Feminizing hormone therapy produces multiple changes in your body that can change your gender presentation. Everyone responds to it differently – some of these changes can take longer to appear, and some may be more or less intense. Your genetics and lifestyle can also influence them. For example, diet and exercise will affect how much your body shape changes. 

    Breast growth

    Breast growth is one of the major changes from estrogen and can help a lot with feelings of dysphoria. However, the amount of growth you get can vary a lot. It will depend on your genetics and what age you started treatment (younger people can get more growth). It can start within a few weeks of treatment, but it might take a few months. It will begin as small “buds” beneath your nipples, and you might have some pain during this growth phase, but it should eventually go away.

    Sometimes breast growth can be uneven, just like people who develop them in puberty. If you’re planning a breast augmentation surgery, you should wait until you’ve been on estrogen for at least one year.


    Within a few months of starting treatment, your skin can change texture. It might become softer and, if you have acne, this could improve. This is because estrogen will make your skin less oily and help it produce more collagen. In some people, your skin may become dry – you can treat this with over-the-counter products. As your skin changes, you might also notice that you sweat less and your sweat smells different.


    Estrogen and blockers can affect the hair on your head, face and body. If you were losing hair on your head before starting hormones, this should stop within the first few months of treatment. You can’t re-grow hair that’s already been lost, but hair transplants are an option if this is distressing for you. There are also prescription and over-the-counter treatments available to restore hair that’s thinning. 

    After a few months your facial and body hair may also get thinner and growth can slow, but it won’t disappear. To remove facial and body hair permanently you can use electrolysis and/or laser treatments.

    Body composition

    Estrogen can change where fat is stored on your body. You might notice more fat in your hips and thighs, and your face might change shape as more fat is stored there. This should start within a few months of treatment. 

    Over time, you’ll also lose muscle mass and strength. Your arms and legs might look less defined than before. It’s a good idea to keep up with exercise after you start treatment, as it helps maintain your general health. If you’d like to reduce your muscle mass then diet and exercise changes can help, but talk to your clinician first.

    Genital changes

    Estrogen and androgen blockers can cause changes to your genitals. In the first few months you might notice that you start having fewer spontaneous erections (e.g. erections when you wake up in the morning). Over time, your testicle size will also decrease. This can cause some discomfort, but it should resolve. Also, some people can have trouble getting and maintaining an erection.

    If erectile dysfunction is bothering you, then prescription medications like Viagra and Cialis can help. You can also reduce your dose of androgen blockers. Talk to your clinician and they can find what’s best for you.

    Mood and sex drive

    Along with physical changes, estrogen can affect how you think and feel. Gender-affirming care as a whole can improve depression, anxiety and self-esteem as you become more comfortable. However, estrogen specifically can cause mood changes. For example, you might find that you feel more sensitive or cry more. If you have any pre-existing mental health conditions it can affect these too. Before starting treatment, talk to your clinician about your mental health history and they can help you monitor any changes in mood.

    One common effect of hormone therapy is that your sex drive changes. It can reduce your libido and, along with changing your body, can change the kind of sex you’re into. You might also notice a change in who you’re attracted to. Communicating openly with any partners you may have can help you figure out what works best for you.

    Timeline of changes

    If you have friends on hormones or read transition diaries online, they might tell you when certain changes will happen. It can feel frustrating if your progress doesn’t match someone else’s timeline, but don’t worry! There’s a fairly wide range in when changes can start and when they reach their maximum effect. Based on information from Rainbow Health Ontario, this is when these can happen for most people:

    ChangesOnsetMaximum effect
    Scalp hair loss stops1-3 monthsVariable
    Lower libido1-3 months3-6 months
    Less spontaneous erections1-3 months3-6 months
    Softening/less oily skin3-6 monthsUnknown
    Body fat redistribution3-6 months2-3 years
    Decreased muscle mass/strength3-6 months1-2 years
    Breast growth3-6 months1-2 years
    Decreased testicular volume3-6 months2-3 years
    Thinned/slowed growth of facial and body hair6-12 months3+ years
    Decreased sperm productionUnknown3+ years
    Erectile dysfunctionVariableVariable

    Verified answerPermanent vs temporary changes

    Some changes from hormones, like your mood or sex drive, are temporary. This means that if you stop treatment they will eventually reverse.

    Other changes like breast growth are permanent. This means you can stop treatment and they will remain.

    Some people choose to stop hormones after reaching permanent changes that they’re happy with, while others will continue for the rest of their lives. You can decide whatever works best for you and your body – and remember, you can adjust your treatment at any time.


    Everyone’s gender is unique. Just like there’s no one way to be trans, there’s no one dose for estrogen. You can work with your clinician to figure out what works best for you, based on the physical effects you’d like to see from treatment. 

    Starting dose

    When you start estrogen and/or androgen blockers, your clinician may prescribe a low dose and increase this over time. If your goal is a higher dose, you’ll work your way up to this. The speed depends on how you respond to treatment and any side effects you’re having. The maximum dose will put your estrogen levels in the normal range for someone assigned female at birth. 

    In your first year of treatment you’ll be monitored at 1, 3, 6 and 12 months. You will have your blood taken to check your hormone levels and monitor other things like kidney function. After your first year of treatment, if everything is stable, you’ll only need your hormone levels checked once a year.

    Increasing or lowering dose

    You and your clinician can adjust your dose at any time. Increasing your dose can intensify the changes estrogen makes to your body. Reducing your dose can help if you’re having undesirable side effects. It’s important to remember, though, that adjusting your dose won’t reverse permanent changes like breast growth.


    Some people will stay at lower doses for more gradual physical effects (often known as “microdosing”). This is generally easier with topical estrogen, because you have more control over your dose. Microdosing can slow down the pace of changes but it won’t change which ones are temporary or permanent. If you’d like to microdose your hormones, you can discuss this with your clinician at your planning appointments.

    Stopping hormones

    Not all trans, non-binary and gender-diverse people stay on hormone therapy, and there’s many reasons you might stop treatment. Maybe you’re having side effects, or maybe you want to have a biological child or bank sperm. Some people also stop because they’re happy with the permanent changes they’ve had. 

    Some people might feel guilt or shame about stopping treatment. It’s important to know that hormone therapy doesn’t define you – whatever your treatment journey is, your gender and your experience are valid. At Foria, we’ll support whatever treatment path you decide to take. It can be scary to talk to your clinician about stopping hormones, but it’s essential to make sure you’re doing it safely. For example, you may need to start other medications if you’ve had bottom surgery. 

    If you’ve stopped hormones for non-medical reasons, you can start again at any time. Your treatment plan when you restart will depend on your previous experience with hormones.

    Verified answerDetransitioning

    A small number of people choose to stop treatment permanently, and this is sometimes known as "detransition" or "retransition". This can happen even if someone’s had positive outcomes from treatment. There can be many reasons for detransitioning, like mental health challenges, discrimination, or a change in how someone experiences their gender. Detransition doesn’t always include feelings of regret. In fact, researchers who study gender-affirming care have found that many people who detransition don’t regret their experiences of treatment. 

    Things to look out for

    There are a few health risks that come with estrogen and androgen blockers. Your clinician will go over these before you start treatment and monitor you closely throughout to keep an eye on them. Regular blood work can be annoying, but it’s important!


    If you’re thinking about having a biological child in the future, it’s a good idea to talk to your clinician before you start hormone therapy. This is because hormones can reduce your sperm count, making it harder to conceive. Freezing sperm before starting treatment can give you more options when it comes to family planning.

    If you’ve already started hormones and would like to have a child, then you can pause your treatment. Your sperm count can improve after going off hormones for a few months, which allows you to preserve sperm or embryos. However, this can be hard to predict and there’s a lack of research on if or when sperm count will improve after pausing hormones. This can also be affected by how long you were on these medications (a urologist or fertility specialist can give you advice on this).

    Although estrogen and blockers can reduce fertility, they’re not a contraceptive. This means it’s possible to get someone pregnant while you’re on hormones. If you haven’t had bottom surgery and your sex partner has a uterus, talk to your clinician about what contraceptives are best for you.

    Health issues

    Estrogen can raise your risk of blood clots, which can very rarely cause heart attacks and strokes. Estrogen in any form raises this risk – whether it’s taken for menopause symptoms or as birth control. People who make their own estrogen also have higher risk when their body is producing more, like in pregnancy. Older age can increase this risk, along with smoking and high cholesterol or blood pressure. The good news is that simple things like quitting smoking or getting more exercise can lower this risk.

    Estrogen and blockers could raise your risk of certain cancers. If you’re taking estrogen, you should be screened for breast cancer in the same way as people who develop breasts in puberty. A family history of breast cancer or certain gene mutations can put you at higher risk. You can monitor this by following breast screening guidelines.

    The blocker cyproterone has also been linked to rare cases of brain cancer but this was seen at much higher doses than what is now prescribed. Higher doses of cyproterone are also linked with liver inflammation and depression, but it’s unlikely with the doses used today. When cyproterone is taken with estrogen it can increase a hormone called prolactin – a certain kind of benign brain tumor can also produce this hormone, so if this happens you’ll need some tests to rule that out.

    Getting started with estrogen

    Interested in starting estrogen? Foria’s clinicians can guide you through your options when it comes to gender-affirming care. If hormone therapy is right for you, they can work with you to build a treatment plan that reflects your goals. If you’re re-starting hormones we can also guide you through this, and we can transfer your care if you’re already on treatment but would like to use Foria.

    If you'd like to learn more about Foria's hormone therapy program, visit our estrogen service page.

    This content has been reviewed by Foria’s Medical Director, Dr. Kate Greenaway and our community advisory team. Medical sources include Rainbow Health Ontario’s Guidelines for Gender-Affirming Primary Care with Trans and Non-Binary Patients, Fenway Health, Mayo Clinic and the UCSF Transgender Health Guide.

    Foria's clinical team

    by Foria Clinical Team

    minute read

    Share article

    Share on FacebookShare on Twitter