Side effects of hormone therapy

Side effects can happen with any type of treatment for cancer, but everyone’s experience is different. Some people have many side effects. Other people have few or none at all.

If you develop side effects, they can happen any time during, immediately after or a few days or weeks after hormone therapy. Sometimes late side effects develop months or years after hormone therapy. Most side effects go away on their own or can be treated, but some side effects may last a long time or become permanent.

Side effects of hormone therapy will depend mainly on the type of hormone therapy, the dose of a drug or combination of drugs and your overall health.

It is important to report side effects and your concerns about side effects to the healthcare team. Doctors may measure how severe certain side effects are. Sometimes hormone drug therapy may need to be adjusted if side effects are severe.

The following are the most common side effects that people tend to experience with hormone therapy.


Fatigue is a general tiredness and lack of energy that can occur with hormone therapy. It makes a person feel more tired than usual and can interfere with daily activities and sleep. It tends to be worse when you are having other treatments, such as chemotherapy or radiation therapy. Fatigue may get better as time goes by, but it can sometimes last for a long time after hormone treatment.

Nausea and vomiting

Nausea and vomiting can occur with some hormone therapy drugs. These side effects usually get better as the body gets used to the drug. Taking hormone therapy drugs with food or at bedtime may help relieve these side effects.

Nausea and vomiting can also occur a few hours after radiation therapy to the abdomen.

Weight gain

Weight gain often occurs with hormone therapy. It is caused by increased appetite, less activity and fluid retention. It is often difficult to control weight when you are having hormone therapy but changes in diet and exercise may help. You can ask to see a dietitian about managing your weight.

Less or loss of interest in sex

Less or loss of interest in sex can occur with some hormone therapies. It may continue as long as hormone drug therapy is taken, but sometimes can be a long-term side effect. It can be a permanent side effect if surgery or radiation therapy is done to stop hormone production.

Find out more about sexuality and cancer.

Treatment-induced menopause

Treatment-induced menopause can be permanent in women who have their ovaries surgically removed or have radiation therapy to the ovaries. Treatment-induced menopause in women who have had hormone drug therapy may be temporary. For some women, it can be permanent, especially if they are near natural menopause when hormone drug therapy starts.

Symptoms of treatment-induced menopause are the same as symptoms of natural menopause, but they may be more severe because treatment-induced menopause happens quickly.

Hot flashes

Some hormone therapies can cause hot flashes and sweating in both men and women. These side effects usually get better as the body gets used to the treatment or when the hormone drug therapy is stopped.

There are ways to manage hot flashes. Taking hormone therapy drugs at night may help some people cope with hot flashes. If hot flashes are worse at night, take the drugs in the morning.

Check with your doctor or healthcare team before taking herbal products to treat hot flashes because some may have hormone properties that can affect a hormone-related cancer.

Breast swelling or tenderness

Some hormone drug therapies can cause breast swelling or tenderness in men and women.

Erectile dysfunction

Erectile dysfunction (ED) is also called impotence. ED is when a man cannot keep an erection sufficient for sexual intercourse. This may be a long-term side effect of hormone therapy. Some men may experience ED as a result of certain hormone treatments for prostate cancer.

  • ED can be temporary with hormone drug therapy. It can take 3 to 12 months after hormone drug therapy stops to regain erectile function. If erectile function does not come back on its own, several treatments are available, including prosthetic penile implants, vacuum devices and medicines.
  • ED is usually permanent if both testicles are removed.

Fertility problems

Fertility problems can be temporary or permanent. A permanent loss of fertility (infertility) can be caused by surgical removal of the testicles or ovaries. Hormone drug therapy and radiation therapy can also cause a temporary or permanent loss of fertility.

Tumour flare reaction

A tumour flare reaction or a tumour flare response, such as bone pain, may worsen when certain hormone drug therapies are first used. A tumour flare reaction is a temporary side effect and usually goes away after a few weeks. Sometimes anti-androgens are given before or along with LHRH agonists for several weeks to reduce the chance of tumour flare reaction.


Diarrhea is an increase in the number and looseness of stools. It occurs because some hormone therapy drugs affect the cells that line the gastrointestinal (GI) tract. Factors that increase the risk of diarrhea include the type and dose of hormone drug therapy used.

Muscle or joint pain

Muscle or joint pain may occur a few days after hormone drug treatment begins. Taking medicines such as acetaminophen (Tylenol, Atasol) can help reduce this side effect.

Blood clots

A blood clot may develop in your leg or lung during hormone therapy. Symptoms include calf tenderness, a hardened vein, pain or swelling in the legs, trouble breathing and chest pain. If you have any of these symptoms, see your doctor or go to the nearest emergency department immediately. A blood clot is treated with a blood-thinning medicine.


Osteoporosis is a loss of bone density. It is a long-term side effect that may occur with some hormone drug therapies. You may have a bone mineral density test before starting hormone drug therapy. This test gives a baseline for comparison with follow-up tests. Bone loss can be prevented and managed with calcium and vitamin D supplements, physical activity and other drug therapy.

Information about specific cancer drugs

Other side effects may occur with hormone drug therapy. Find out more about sources of drug information and where to get details on specific drugs.

Expert review and references

Medical disclaimer

The information that the Canadian Cancer Society provides does not replace your relationship with your doctor. The information is for your general use, so be sure to talk to a qualified healthcare professional before making medical decisions or if you have questions about your health.

We do our best to make sure that the information we provide is accurate and reliable but cannot guarantee that it is error-free or complete.

The Canadian Cancer Society is not responsible for the quality of the information or services provided by other organizations and mentioned on, nor do we endorse any service, product, treatment or therapy.

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