Side effects of hormone therapy in men

Many men find that the side effects are often worse at the start of treatment. They usually settle down after a few weeks or months.

The side effects you might have depend on the type of hormone therapy that you are having. 

Some side effects are common to all hormone therapies. Some vary from drug to drug. You might not have all of these side effects. 


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

Problems getting an erection (impotence)

Hormone therapy lowers the amount of testosterone in the body and this affects your ability to have and maintain an erection. This may get better within 3 to 12 months after the treatment ends.

For some men, erection problems are permanent. It depends on the drug you are having and how long you have been taking it.

Your doctor or clinical nurse specialist will be able to offer you advice.

Hot flushes and sweating

Hot flushes and sweating can be troublesome. They may last for 2 to 30 minutes and you may have a few a month or more often. They are the same as the hot flushes women have when going through menopause.

Lowered testosterone levels cause hot flushes.  They are most likely to happen when taking LHRH agonists, also called LH blockers Open a glossary item, because these drugs cut testosterone production off altogether.

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

They may gradually get better as you get used to the treatment. But, in some men the flushes keep on happening as long as you take the drug.

Talk to your doctor or clinical nurse specialist if you have problems coping with hot flushes and sweating. There are treatments that may help.

Breast tenderness (gynaecomastia)

Breast tenderness is a particular problem with high dose bicalutamide (Casodex). The breast tissue can become painful and swollen.

You might have a hormone therapy called tamoxifen to help with this. Or you might have a small dose of radiotherapy before treatment starts. 

Pain from tumour flare

Pain caused by a secondary prostate cancer can temporarily worsen when you start hormone treatment. This is called tumour flare.

Your doctor should always prescribe another hormone therapy when you start leuprorelin (Prostap) or goserelin (Zoladex) injections. This other hormone therapy helps to prevent tumour flare from causing bone pain. If the pain carries on, your doctor can prescribe drugs called bisphosphonates to treat it.

Weight gain

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

Memory problems

Some people feel that their memory gets worse when they have been having hormone treatment for a while. Your memory may not improve while you are taking the hormone treatment. But there are ways to make life easier, such as making lists so you don't forget things.

It is natural to feel cheated and upset if you have this particular side effect. Talk to your doctor or specialist nurse if you feel this is having a significant effect on your life.

Mood swings and depression

Some people have mood swings and even depression while having treatment such as Zoladex (goserelin). 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.

Bone changes

Men taking hormone therapy for prostate cancer are at risk of bone thinning (osteoporosis). There is evidence that the risk of problems such as bone fractures is slightly higher for men having long term treatment to block testosterone (for example, Zoladex). Your doctor may suggest taking vitamin D and calcium to help lower your risk of problems from osteoporosis.

It might help to:

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

Risk of heart problems

Hormone therapy for prostate cancer might increase the risk of heart problems if you have certain medical conditions.

This may be because some of the side effects of hormone therapy, such as weight gain, can make heart disease worse.

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 August 2019

  • British National Formulary 

    Accessed August 2019

  • Gynecomastia in Patients with Prostate Cancer: A Systematic Review

    A Fagerlund and others

    PLOS ONE, 2015

  • Treatment Of Osteoporosis in Men

    UpToDate, Accessed August 2019

  • Cardiovascular effects of hormone therapy for prostate cancer

    J Lester and D Mason,

    Drug, Healthcare and Patient Safety, 2015. Volume 7

  • Cognitive Effects of Androgen Deprivation Therapy in Men With Advanced Prostate Cancer

    B Gunlusoy and others

    Urology, 2017. Volume 103

Last reviewed: 
27 Jan 2021
Next review due: 
27 Jan 2024

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