What effects does it have?

What is it?

Hormone with many effects including fat redistribution, skin thinning and breast growth.

It's also known as Oestrogen, Estrogen, Estradiol, or 17β-estradiol.

How long does it 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.

More information


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.


Taking oestrogen causes development of breast tissue, and all people who have taken oestrogen should be aware that they 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.

Oestrogen is commonly available in oral (pill or tablet) form, transdermal patches (patches that are stuck to the skin), gels applied to the skin, and as depot injections or implants 1.

There are several different variants of oestrogen available. In the UK, oestrodiol valerate or oestrodiol hemihydrate are normally used, but cypionate or bezoate are also available and have a longer lasting effect. 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 2 and are not detectable in normal blood tests.

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. Oestrogen does not change the shape of the pelvis (hip bones) in adults.

Oestrogen may have positive effects on your mood. Many transgender women taking oestrogen reporting a calmer mood 1.

In combination with oestrogen therapy most people will also wish for testosterone to be reduced. Antiandrogens (in the UK, normally GnRH agonists) are the most common approach for testosterone suppression 4, though some endocrinologists may use high doses of oestrogen for testosterone suppression instead where possible 5. If this is performed, the side effects of testosterone reduction can include genital shrinkage and temporary or permanent infertility.

Costs and funding

If you have received a formal diagnosis, the NHS will normally provide oestrogen therapy and treatment with GnRH agonists.

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. If your GP agrees, the cost of your medication is funded by the NHS. If your GP does not, the private service can write you private prescriptions, which you will have to pay the full cost of.

For oestrogen therapy to begin, it is required that any other significant medical or mental health issues are “reasonably well controlled” 6. This means that a medical professional is currently helping or has helped you manage the condition.

Oestrogen therapy is not usually provided to under-18s, 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 7.


  1. 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.
  2. 2 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.
  3. 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.
  4. 4 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.
  5. 5 Devon Partnership NHS Trust (2017) “PG12 Pharmacological Treatment of Gender Dysphoria.”
  6. 6 Royal College of Psychiatrists (2013) “Good practice guidelines for the assessment and treatment of adults with gender dysphoria.” [online] Available from: www.rcpsych.ac.uk/usefulresources/publications/collegereports/cr/cr181.aspx
  7. 7 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.” [online] Available from: https://www.england.nhs.uk/commissioning/wp-content/uploads/sites/12/2016/08/clinical-com-pol-16046p.pdf

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Page last updated: September 2017