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Hormone replacement therapy (HRT) - explained

Hormone replacement therapy (HRT) is the most common medical treatment of menopause. There's a lot of confusion about the risks and benefits of HRT - and it can be hard to understand whether it might help you. This article explains what HRT is, the different forms and it's pros and cons.

What is hormone replacement therapy (HRT)?

HRT is a type of medication which you can take to help ease symptoms of menopause. It comes in many different forms, but it will always have a form of the hormone oestrogen in. If you've had a hysterectomy in the past, you'll be given oestrogens alone. If you haven't had a hysterectomy, oestrogen will be combined with a form of progesterone. HRT with both oestrogen and progesterone in is sometimes called 'combined HRT'. The type of HRT recommended for you will depend on your medical history, symptoms, preferences and whether you have periods or not.

More about estrogens (replacements for our hormone oestrogen)...

There are synthetic (man made) and natural estrogens available. Synthetic estrogens are not commonly used as HRT, unless you are experiencing menopause under 40 and have been diagnosed with premature ovarian insufficiency (POI).

Natural estrogens are from plants or animals - but always found in natural living things rather than from chemicals. Natural estrogens used in HRT include estradiol, estrone and estriol - from soybeans or yams mostly. Premarin, a well known form of HRT, uses estrogen from horses. If you are curious about oestrogen therapy alone, have a read of our Oestrogen hormone therapy article.

More about Progestogens (replacements for our hormone progesterone)....

Using oestrogen only HRT in women with uteruses increases the risk of some diseases - so combined HRT is now recommended. This means taking a form of progesterone in addition to oestrogen if you still have a womb. The progestogens used for HRT are mostly synthetic. They are taken as tablets, though there are different ways to take HRT.

The progestogen will often be used cyclically in perimenopausal women - this means taken for two weeks and then taking a break from the progesterone part of the HRT. When on a break there will be a withdrawal bleed. Check out our progesterone hormone therapy article to learn more about this.

For post menopausal women continuous progestogens use is recommended.

Tablet/orally taken HRT

Taking tablets is the most common way to take HRT. This doesn't necessarily mean it's the best way to take it though. There have been continuous developments with patches and gels, making them a viable alternative.

The main reason not to take HRT as tablets is to avoid the impact they may have on your gut and liver. When you take pills they are digested through our normal systems, meaning that they'll pass through your gut and the liver. Estrogens taken through the mouth will also leave the chemical estrone circulating in the body. Estrogens taken non-orally leave the hormone estradiol in the body. These two hormones have slightly different effects.

To get the best effects women may need to take different forms and doses of HRT - mixing tablets, patches and/or gels in many cases.

Patches and gels

Both estrogens and some progestogens (specifically norethisterone and LNG) can be absorbed through the skin. There are two main ways to do this - via patches and gels. This means that these forms of HRT can be applied directly to your skin - hormones are then absorbed into your body.

Patches can be cut into different sizes, to control dosing. They usually need to be replaced twice a week. The specific advice will depend on the brand of HRT you are taking, and the instructions on the packet. Patches can be applied cyclically or continuously - meaning that they are suitable for peri and post menopausal women.

Gel is only available for estrogen HRT. This means for women who still have a womb, they would need a tablet form of progesterone to accompany the gel.


Implants are inserted under the skin and release the hormones estradiol gradually into the body. They need to be inserted and replaced every 6 months. Implants give a higher dose of estradiol than other forms of HRT - which some women find helpful. They also become very useful if you struggle to remember to take daily tablets.

Something to consider with implants, however, is that it's harder to control the dose of estrogen you are recieving. This is because upon insertion they start releasing hormones at a set level. Unfortunately, for some women, the dose of hormones from an implant will not be enough to cause their symptoms to stop. Implants are also likely to leave a small amount of estradiol circulating after they have run out. The risks attached to this residual hormone are not yet well understood.

When to start HRT?

You don't have to wait until your periods stop to start HRT - You can safely take HRT whilst still on your periods. If your having symptoms which are causing you trouble and you are open to hormonal therapy you should speak to your GP.

If you choose to start HRT you may have to try out different forms and doses over a few months to get those pesky symptoms under control. There may also be some additional side effects before you find the right dose for you. Stick with the advice from a doctor until you work out the right treatment for you.

What are some of the common side effects of HRT?

Estrogens can cause:

  • bloating/water retention
  • breast tenderness
  • nausea
  • headaches
  • leg cramps.

Progestogens can cause:

  • bloating/water retention
  • breast tenderness
  • mood swings
  • Depression
  • Back pain
  • headaches.

For vaginal symptoms only...

There are different types of HRT if you are looking for relief from vaginal symptoms only e.g. dryness, pain during sex, or recurring infections. You can take low dose creams or tablets which are directly applied to the vagina. For these symptoms you take estradiol only - the low dose is considered safe for all women. If you're only taking vaginal oestrogen there is no need for any progesterone.

And finally, a little note on testosterone...

It's normal for testosterone levels to drop with age - but for some women (especially those who have their ovaries removed) they can lose a huge amount. Symptoms of low testosterone include loss of libido, mood issues, fatigue and headaches. Testosterone replacement therapy may help women, but currently there are not any testosterone products licensed for women in the UK. This is something we're hopeful will change quickly.

For women with low testosterone some doctors will recommend testosterone gels, produced for men. Women can use these in small amounts to help get relief from symptoms. Often, this would be with a estrogen based therapy.

Overall some of the pros of HRT are:

  • It can help women with horrible symptoms. It is the most effective way to reduce many menopausal symptoms at the moment, but therapy based approaches (CBT) can also be very effective.
  • The highest quality research (Cochrane Systematic reviews) show that HRT started within 10 years of menopause can reduce the risk of CHD and all cause mortaility [1].
  • Treating vaginal symptoms with low dose HRT directly applied to the area is an effective way to help with vaginal dryness and low sex drive (both very common symptoms).

Some considerations are:

  • There may be a slight increase some cancers when estrogen and proestogen combined are used. It's a small but significant increase in risk - but each person should weight these up against the benefits of HRT.
  • There's no one size fit all approach to HRT. It can be quite labour intensive to get the right combination of HRT for you. You'll want to track and monitor your symptoms over the first few months to ensure you're on the correct dose.
  • Treatment always needs to be specific to the indivdual, and once the right HRT is found a doctor should still review it annually.


  1. Main, C., Sanchez, G., Knight, B., Sanchez-Gomez, L., Roqué M Figuls, M. and Cosp, B., 2013. Hormone Therapy for preventing cardiovascular disease in post-menopausal women. Cochrane Library, [online] (2).
    Available at: https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD002229.pub3/full.

  2. Hillard, T., Abernathy, K., Hamoda, H., Shaw, I., Everett, M., Ayres, J. and Currie, H., 2017. Management Of The Menopause. 6th ed. British Menopause Society.

  3. nhs.uk. n.d. Menopause. [online]
    Available at: https://www.nhs.uk/conditions/menopause/ [Accessed 16 October 2019].