What is oestrogen?
Hormone with many effects including fat redistribution, skin thinning and breast growth.
It's also known as Oestrogen, Estrogen, Estradiol, or 17β-estradiol.
Oestrogen is a component in many hormone-based contraceptives; see contraceptive pill.
What does oestrogen do?
The extent of the effects vary between people. Most people experience these effects:
- Upper body
Makes breasts grow
- Lower body
More hips and buttock fat, reduces erections
Often calms or improves mood
Changes body odour
Occasionally, people experience these effects:
- Facial hair
Who can have oestrogen?
You need to have had persistent dysphoria, but there is no specific time frame
You must have capacity to consent for this treatment
If you have significant medical conditions, these need to be “reasonably well-controlled”
You usually need to be at least 16
How long does oestrogen last?
Some of the effects of oestrogen (including breast growth) are permanent and start within 2-3 months. Changes may take several years to reach their full effect.
How do I stay safe?
There are a number of health risks associated with hormone therapies. It’s important to get regular blood tests, both to spot problems before they arise and to make sure your dosage is correct.
Taking oestrogen causes development of breast tissue. If you have taken oestrogen, you are at risk of breast cancer.
There is no recommended method for breast self-examination in the UK, but you should learn how your breast tissue feels and looks and see a doctor if you experience any unexpected changes.
Re-using needles puts you at risk of infection.
If you’re taking this as an injection, it’s important to use sterile needles that are disposed of properly. If you are injecting yourself, you can find lots of safety information on our self-injection page.
If your injections are being done by a doctor or nurse, they should make sure the needles are sterile and dispose of them properly.
What should I be aware of?
Taking oestrogen may increase the risk of thromboembolic disease (problems caused by blood clotting like deep vein thrombosis), prolactinoma, gallstones, and liver problems. These risks can be reduced by regular blood testing, stopping smoking, and maintaining a healthy lifestyle 1.
While oestrogen does reduce production of sperm, it does not provide adequate contraception 2 and does not effectively prevent pregnancy.
Why might I want oestrogen?
Effects of oestrogen include:
The amount of breast development varies significantly from person to person, can take months to begin, and may not be complete for many years 3.
Changes in fat distribution
Oestrogen can cause an increase in size of hips and buttocks by enlarging skin fat deposits around these areas 1, but this may take up to five years 3, and does not change the shape of the pelvis (hip bones) in adults. Changes in fat distribution may also cause subtle changes to the appearance of your face.
Oestrogen may have positive effects on your mood. Many transgender women taking oestrogen reporting a calmer mood 1. The exact effects vary from person to person.
Oestrogen therapy can also have a number of other effects including changes in skin softness and appearance and body odour. Oestrogen has no effects on the voice, and patients who wish to make changes to their voice should instead consider speech therapy).
In combination with oestrogen therapy, most people will also wish for testosterone to be reduced. Some endocrinologists may use high doses of oestrogen for testosterone suppression 4, p.12, although this is often unsuccessful and commonly a lower dose of oestrogen in combination with antiandrogens (in the UK, normally GnRH agonists) is the most common approach for testosterone suppression 5, p.170.
Why might I not want oestrogen?
When used in combination with an antiandrogen such as GnRH agonists, effects of oestrogen therapy that you might find undesirable are:
Changes in arousal
Oestrogen and antiandrogen therapy can cause changes to sexual arousal, reducing frequency of spontaneous erections 3, and sometimes making it difficult to maintain erections, and can significantly reduce the amount of ejaculate over time down to little or none 6, p.138.
Changes in libido
Oestrogen and antiandrogen therapy can cause changes in interest in sex, often decreased libido 3.
Loss of strength
Oestrogen and antiandrogen therapy often causes a significant reduction in strength and muscle mass 3.
Oestrogen and antiandrogen therapy can reduce sperm quality 6, p.138 and may eventually cause infertility.
What kinds are there?
Oestrogen is commonly available in oral (pill or tablet) form, transdermal patches (patches that are stuck to the skin), and gels applied to the skin1, p.237. It is very rarely available as an implant, although these are not commonly used. Oestrogen injections are not available in the UK.
There are several different variants of oestrogen available. The two main variants used in the UK are oestradiol valerate (as pills) and oestradiol hemihydrate (as pills, patches, and gel). In the past, ethinylestradiol and conjugated equine oestrogens were used, but these are now avoided because they have a much higher risk of blood clots 7 and are not detectable in normal blood tests.
How much will it cost?
If you have received a formal diagnosis, the NHS will normally provide funding for oestrogen therapy and treatment with GnRH agonists. Oestrogen therapy is not usually provided to under-18s on the NHS, with the effects of hormones during puberty being stopped by GnRH agonists until the age of 18 when oestrogen therapy can be commenced. Some services may additionally provide oestrogen to selected 16 and 17 year old people 8.
Under some circumstances, it may be possible to get hormone therapy from the NHS without a diagnosis.
You do not have to pay the full cost of medication you are prescribed on the NHS. You are not asked to pay anything at all in Northern Ireland, Scotland and Wales. In England, people are asked to pay a small charge for each item on their prescriptions. There are ways you can reduce or avoid this cost, which you can read about on the NHS website.
If you are using private gender services, the service will normally ask your GP to write you NHS prescriptions. Your GP may or may not agree to do this - it is up to them. NHS England have published guidance for GPs to help them make this decision, which you may wish to give to your GP. If your GP agrees to prescribe, the cost of your medication is the same as any other NHS prescription. If your GP does not, the private service can write you private prescriptions, which you will have to pay the full cost of.
- 1.Seal, Leighton J (2017) “Hormone Treatment for Transgender Adults,” in Bouman, W. P. and Arcelus, J. (eds.), The Transgender Handbook: A Guide for Transgender People, Their Families and Professionals, Nova Science Publishers Inc, pp. 227–249. Link
- 2.FSRH Clinical Effectiveness Unit (2017) “Contraceptive Choices and Sexual Health for Transgender and Non-binary People.” Link
- 3.Hembree, Wylie C, Cohen-Kettenis, Peggy, Delemarre-Van De Waal, Henriette A, Gooren, Louis J, et al. (2009) “Endocrine treatment of transsexual persons: an Endocrine Society clinical practice guideline.” The Journal of Clinical Endocrinology & Metabolism, 94(9), pp. 3132–3154. Link
- 4.Devon Partnership NHS Trust (2017) “PG12 Pharmacological Treatment of Gender Dysphoria.” Link
- 5.Seal, Leighton J (2007) “The practical management of hormonal treatment in adults with gender dysphoria,” in Barrett, J. (ed.), Transsexual and other disorders of gender identity: A practical guide to management, Radcliffe Publishing, pp. 157–190. Link
- 6.Adeleye, Amanda J, Reid, Garrett, Kao, Chia-Ning, Mok-Lin, Evelyn and Smith, James F (2019) “Semen parameters among transgender women with a history of hormonal treatment.” Urology, 124, pp. 136–141. Link
- 7.Toorians, AWFT, Thomassen, MCLGD, Zweegman, S, Magdeleyns, EJP, et al. (2003) “Venous thrombosis and changes of hemostatic variables during cross-sex hormone treatment in transsexual people.” The Journal of Clinical Endocrinology & Metabolism, 88(12), pp. 5723–5729. Link
- 8.NHS England Specialised Commissioning Team (2016) “Clinical Commissioning Policy: Prescribing of Cross-Sex Hormones as part of the Gender Identity Development Service for Children and Adolescents.” Link
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