Side effects of hormone therapy

Like all treatments, hormone therapy can cause side effects. Make sure you discuss these with your doctor or nurse before you start treatment. Or you can call our Specialist Nurses or speak to a nurse online if you have any concerns.

We describe here the most common side effects. It may seem like there are a lot, but you may not get all of them, and there are ways to manage them. Hormone therapy affects men in different ways.  Some men have few side effects or may not have any at all.

Side effects usually last for as long as you are on hormone therapy. If you stop treatment, some of the side effects will reduce. This may take several months - your side effects won't stop as soon as you finish your hormone therapy.

Possible side effects of hormone therapy include:

Watch Bruce's story: How hormone therapy affected him.

Hot flushes

Hot flushes are a common side effect of hormone therapy. They can be similar to the hot flushes women get when they're going through the menopause. They may happen suddenly without warning or they may be triggered by stress, a hot drink or a change in the temperature around you.

Hot flushes can vary from a few seconds of feeling overheated to a few hours of sweating that can stop you from sleeping or cause discomfort. Some men may not be worried by them, but others find them very disruptive and difficult to deal with. If your hot flushes are affecting your everyday life, speak to your doctor or nurse.

There are a number of things you can do to help manage hot flushes. These include lifestyle changes, drug treatments and complementary therapies. You can read more about hot flushes in our online fact sheet, or in our booklet Living with hormone therapy: a guide for men with prostate cancer.

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Changes to your sex life

Hormone therapy can affect your sex life in different ways.

  • It can change your desire for sex (libido) and may mean you have much less interest in sex.
  • It can cause problems getting and keeping an erection (erectile dysfunction).
  • You may produce less semen, and orgasms may feel different. Although you will still have feeling in your penis and you should still be able to have an orgasm.
  • Hormone therapy may make your penis shorter. And it can also make your testicles smaller.

Read more about these changes and ways to treat them.

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Extreme tiredness (fatigue)

Hormone therapy for prostate cancer can cause extreme tiredness (fatigue). Fatigue can affect your energy levels, your motivation and your emotions. Tiredness may be due to your treatment but it can also have other causes such as the cancer itself or other conditions.

Talk to your doctor or nurse about how tiredness is affecting you. There are ways to help manage it. There is our Get back on track service, a telephone support programme designed to help you manage your fatigue so you can do more things you want to do. You might find that your tiredness improves over time.

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Weight gain

Hormone therapy may cause you to put on weight, particularly around the waist. You may find that you start to put on weight soon after starting hormone therapy.  Some men find this physical change difficult to cope with, particularly if they have never had any problems with their weight in the past.

Physical activity and a healthy diet can help you stay a healthy weight. But it can take some time to lose the weight you put on during hormone therapy. If you are finding it difficult to lose weight, ask to be referred to a weight loss programme.

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Strength and muscle loss

Testosterone plays an important role in the physical make up of men's bodies. Compared with women, men usually have less body fat and more muscle strength. Hormone therapy can cause a decrease in muscle tissue and an increase in the amount of body fat.  This can change the way your body looks and how physically strong you feel.

Regular resistance exercise may help to reduce muscle loss and keep your muscles strong.

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Breast swelling and tenderness

Hormone therapy may cause swelling (gynaecomastia) and tenderness in the chest area. The amount of swelling can vary from a small amount of swelling to a more noticeably enlarged breast. Tenderness can affect one or both sides of the chest and can range from mild sensitivity to ongoing pain.

Breast swelling and tenderness are more common if you take anti-androgen tablets such as bicalutamide on their own. If you take oestrogen tablets, you may also get breast swelling.

Breast swelling and tenderness can make some men feel uncomfortable or embarrassed about their bodies. But there are treatments available which can help prevent or reduce these side effects. These include:

  • treating the breast area with a single dose of radiotherapy
  • tablets called tamoxifen
  • surgery to remove some of the breast tissue.

You can read more about breast swelling and tenderness in our online fact sheet.

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Loss of body hair

Some men find that they lose their body hair while they are on hormone therapy. This is because body hair is linked to the production of testosterone, so when testosterone is reduced, you might lose some of it. The hair should grow back if you stop hormone therapy.

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Bone thinning

Testosterone helps to keep bones strong. Because some types of hormone therapy reduce the amount of testosterone in your body, long-term treatment may cause your bones to gradually lose their bulk. This can happen within 6 to 12 months of beginning treatment and the amount of bone loss may increase the longer you are on treatment.

If bone thinning is severe, it can lead to a condition called osteoporosis, which can increase your risk of bone fractures. If you already have osteoporosis, have a family history of osteoporosis or have had fractures in the past, talk to your doctor before you start treatment with LHRH agonists or have an orchidectomy.

There are a number of ways to reduce your risk of bone thinning, including lifestyle changes such as exercise and changes to your diet, and treatments. Read more in our online fact sheet.

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Risk of heart disease and diabetes

Hormone therapy may increase your risk of heart disease and diabetes.

You may be able to help reduce your risk by:

  • eating a healthy diet
  • being physically active
  • limiting the amount of salt you eat
  • avoiding smoking
  • cutting down on alcohol.

Talk to your GP about how often you should have regular health checks.

Read more about healthy eating and physical activity.

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Memory and Concentration

Testosterone may be linked to men's memory and concentration. Some studies have suggested that hormone therapy could affect this. But we don't know for sure whether any changes are caused by the hormone therapy or by something else. For example, feeling tired, stressed or anxious can all affect your memory or ability to concentrate. And these problems can happen as you get older.

Whatever the cause, you may find problems with memory or concentration very frustrating. There are things you can do which might help.

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Changes to your mood

Hormone therapy itself can affect your mood. You may find that you feel more emotional than usual or just 'different' to how you felt before. Some men find that they cry a lot. You may also find that you get mood swings, such as getting tearful and then angry.

Some of the other side effects of hormone therapy are hard to come to terms with. Physical changes, such as putting on weight, or changes to your sex life, might make you feel very different about yourself. Sometimes men describe feeling less masculine as a result of their diagnosis and treatment. Some men experience low moods, anxiety or depression, which could be a result of the hormone therapy or your cancer.

There is support available if you want it.

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You can find a full list of references used to produce this page in our online fact sheet.