Side effects of hormone therapy in women

Different hormone therapy drugs cause different side effects. 

This page tells you about some of the side effects that hormone therapy may cause. Your healthcare team will tell you about specific side effects of your own treatment. 

It’s important to remember that you probably won't get every side effect listed, everyone is different. 


You may feel more tired when you are taking hormone therapy.

Vaginal bleeding

Some hormone therapies can cause vaginal bleeding. It is most common when you first start hormone therapy, or if you switch from one treatment to another. 

You might have:

  • a change to your usual periods
  • bleeding between your periods
  • bleeding after you periods have stopped

Tell your healthcare team if you have any of these.

Hot flushes

Hot flushes and sweating can be troublesome. How often you have them and how long they last will vary from person to person.

Getting overheated, drinking tea or coffee, and smoking can all make flushes worse.

Talk to your healthcare team if you have problems coping with hot flushes and sweating. There are treatments that may help.

Menopausal symptoms

You may start your menopause when you begin hormone therapy. This could be temporary or permanent.

Your periods will stop if you are taking a luteinising hormone (LH) blocker. Open a glossary item Your periods may stop or become lighter if you are taking tamoxifen.

You might also get other menopausal symptoms, even if you’ve already had your menopause. For example, you may have vaginal dryness, changes to your mood, sweating and a lowered sex drive.

Some women who experience these symptoms can still get pregnant. Check with your healthcare team about using contraception.

Hair thinning

Some hormone therapies can cause hair thinning. This is usually not noticeable by other people. 

If you are worried about hair thinning and would like tips on ways to cover your hair, you can learn more about hair thinning and cancer drugs.

Muscle and bone changes

You might develop pains in your joints. This often settles down after a few weeks. You can take a mild painkiller to help control aches and pains.

Some hormone therapies such as aromatase inhibitors can cause thinning of your bones.

Tamoxifen can cause bone thinning in pre menopausal women. It doesn’t cause bone thinning in post menopausal women, and it can help to maintain the strength of your bones.

Bone thinning can lead to osteoporosis and bone fractures if it continues for a few years. So, your doctor may treat you with a drug (a bisphosphonate) to strengthen your bones.

It might also help to:

  • stop smoking
  • only drink alcohol within recommended limits
  • take regular weight bearing exercise, such as walking

Digestive system problems

Hormone therapy can cause a few problems with your digestive system. You might:

  • feel or be sick
  • feel constipated
  • have diarrhoea
  • lose your appetite
  • have an increased appetite
  • have indigestion

Talk to your healthcare team if you have any of these side effects. There are often things they can give you to help.

Weight gain

You might put on weight. You should be able to control this with diet and exercise. But it is often difficult to keep your weight down when you are having hormone treatment. Ask to see a dietitian for advice about managing your weight.


Let your doctor or nurse know if you have headaches. They can give you painkillers such as paracetamol to help.

Memory problems

Some people feel that their memory gets worse when they are having hormone therapy and for a while afterwards. There are ways to make life easier, such as making lists so you don't forget things.

Talk to your healthcare team if you feel memory problems are having a significant effect on your life.

Mood changes and depression

Some people have mood changes or feel depressed while having hormone therapy. Talking with someone close to you may help. If you don't feel comfortable sharing your feelings with people you know, seeing a counsellor may help.

Blood clots

Your risk of blood clots (thrombosis) can slightly increase when you take some types of hormone therapy. Tell your doctor if you or a close relative have had a blood clot in the past.

Tell your doctor or call 111 if you have pain, redness or swelling in your legs. Also tell them if you have sudden breathlessness, chest pain, or if you cough up blood.

Remember that the side effects we have listed above are general ones. Tell your doctor or nurse if you have any side effects. They may be able to help reduce them.

  • Electronic Medicines Compendium 

    Accessed February 2024

  • British National Formulary 

    Accessed February 2024

  • Early and locally advanced breast cancer: diagnosis and management
    National Institute for Health and Care Excellence (NICE), 2018 (updated January 2024)

  • Early breast cancer: ESMO clinical practice guideline for diagnosis, treatment and follow-up
    S Loibl and others
    Annals of Oncology, 2023

  • Managing the side effects of tamoxifen and aromatase inhibitors
    Accessed February 2024

  • The information on this page is based on literature searches and specialist checking. We used many references and there are too many to list here. If you need additional references for this information please contact with details of the particular issue you are interested in.

Last reviewed: 
07 Feb 2024
Next review due: 
08 Feb 2027

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