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Hot flushes and sweats

This page tells you about hot flushes and sweats caused by a lowering of the amount of sex hormones in your body. Both men and women can have hot flushes because of cancer or cancer treatment. There is information about


Hot flushes

Hot flushes can be very troublesome. They are one of the most common symptoms women have when they go through the menopause. About 3 out of 4 women going through the menopause (75%) will have hot flushes. But hot flushes can also happen in women and men because of treatment for cancer. They can be very disruptive, affecting your day to day living and making it difficult to sleep. As a result, hot flushes can have a big impact on your quality of life.

Hot flushes are a sudden feeling of warmth that begins in the face and chest and then spreads in waves to the rest of the body. Flushes can happen at any time during the day or night. Their severity varies from person to person.

Hot flushes are often a combination of symptoms including

  • Reddening of the skin
  • Sweating, which can be light or heavy
  • Racing heart (palpitations)
  • Feeling anxious, irritable or panicky

Hot flushes can last between 2 to 30 minutes. Some people have a few each month, while others have them every hour. But for most people it is somewhere in between. The flushes usually carry on for a few months but for some people they can last for years.

Hot flushes and sweats in women

Women having a natural menopause usually find hot flushes become less frequent and less severe during the 5 years after their last period.

We know from research that around 7 out of 10 women (70%) who’ve had breast cancer treatment have hot flushes. They are likely to happen more often and be more severe than in women having a natural menopause. They happen because breast cancer treatments can lower sex hormone production.

woman talking

Research suggests that if you had hot flushes during your menopause you are more likely to have hot flushes as a side effect when you take tamoxifen as a breast cancer treatment. Tamoxifen is a type of hormone therapy. The number of hot flushes you have and their severity is about the same with tamoxifen when compared with women going through a natural menopause.

If you are close to the age that you would naturally start the menopause when you have chemotherapy, you are more likely to go into the menopause and have more severe symptoms.

Hot flushes and sweats in men

Men having treatment for prostate cancer may have hot flushes. Some men can have them for years. We know from research that more than 7 out of 10 men (70%) who have certain hormone therapy drugs, such as goserelin, will have hot flushes. Another type of hormone therapy called anti androgen therapy, such as bicalutamide, is less likely to cause hot flushes but can do so for some men. 

Some men have their testicles removed as a treatment for prostate cancer. This treatment is not used very often these days. About half the men who have this treatment (orchidectomy) have hot flushes.

For many people, hot flushes gradually get better over several months. For some people the flushes last as long as they are having treatment, although they do tend to happen less often over time.


Cause of hot flushes

In the past, doctors thought that hot flushes were caused only by lowering levels of oestrogen in women and testosterone in men. Researchers now suggest that this is part of the process but it may be more complicated than they first thought. They are looking into a number of possible causes.

One example is that the part of the brain called the hypothalamus controls the production of many hormones. This part of the brain also controls our body temperature. It may be that the chemical messengers (neurotransmitters) the hypothalamus produces cause the hot flushes. We need more research to find exactly what causes flushes so that we can develop treatments that work better at controlling them.


Tips on managing hot flushes and sweats

Hot flushes can be difficult to live with. But here are some suggestions that may help. Some may help to reduce the number of hot flushes and make them milder. Others can help you to cope with them.

  • Cut out coffee, tea and nicotine
  • Keep your room cool – use a fan if necessary
  • Spray your face with a cool water atomiser
  • Wear layers of light clothing so you can easily take clothes off if you overheat
  • Have layers of bedclothes to remove as you need to
  • Wear natural fibres such as silk or cotton instead of man made fabrics
  • Cut down on alcohol
  • Sip cold or iced drinks
  • Have a lukewarm shower or bath instead of a hot one
  • Put a towel on your bed if you sweat a lot at night
  • A chillow (cooling pad) can help to keep you cool

If you are taking tamoxifen, try taking half your dose in the morning and half in the evening. Always talk to your doctor before changing the dose of any prescription medicine.

If you are finding it difficult to manage your hot flushes, do talk to your doctor or specialist nurse. There are medicines that may help.


Medicines for hot flushes

The only way to completely stop hormonal symptoms is to take hormones to replace the ones your body is no longer producing. But if you are having cancer treatment that stops you producing hormones, you can’t have hormone replacement therapy (HRT). Doctors recommend that you don’t take HRT if you have had a hormone dependent cancer such as breast or prostate cancer. Even if you have finished treatment they are concerned that HRT may increase the risk of the cancer coming back.

There are a number of different medicines that your doctor may prescribe to help to reduce and control hot flushes. But before taking any of these, there is something important to bear in mind. When researchers want to find out how well a treatment works in a trial, they sometimes test it against a dummy treatment, or placebo. The people taking part in the trial don’t know whether they are taking the new treatment or the placebo. Many of us feel better when taking something that we think will help.

In nearly all trials looking at treatment for hot flushes, people taking the placebo said that their flushes were reduced by about a fifth (20%). It is important to bear this in mind when we are looking at other treatments. If a treatment reduces hot flushes by 20% or less, it may not be better than a placebo. 

You can read about the placebo effect.

Treatments your doctor may suggest include

Vitamin E

A trial of 120 women who had had breast cancer compared vitamin E with a placebo. They found that vitamin E reduced the number of flushes by one a day. The researchers asked the women which they preferred, vitamin E or placebo. Women did not prefer the vitamin E over the placebo. Vitamin E did not cause many side effects, so the researchers suggest it is worth trying as a first treatment.

We need more research to find out how well vitamin E really works and more about side effects.

Anti depressants

Some anti depressant medicines such as venlafaxine can help to reduce the number and severity of hot flushes. In women who have had breast cancer, anti depressants can reduce hot flushes by just over half. But doctors don’t recommend some types of anti depressant, such as paroxetine or fluoxetine, for women taking tamoxifen. These types may interfere with how well tamoxifen works.

For men with prostate cancer, researchers have recently found that venlafaxine can reduce hot flushes by about half. A small trial looking at paroxetine found that it can reduce hot flushes by about a third.

Remember that all drugs have some side effects. Anti depressants can cause a dry mouth, headaches, feeling sick, and loss of appetite.


Gabapentin is a type of anti epileptic drug. It controls fits (seizures) but it can also help to reduce hot flushes. In trials for women with breast cancer, it reduced their hot flushes by about half (50%). It also helped with reducing the severity of hot flushes and how long they lasted. Pregabalin is very similar to gabapentin and this may also reduce hot flushes.

There is less information about how well gabapentin works for hot flushes in men. Trials have shown that it reduces the number of flushes but not as much as in women.

Side effects of gabapentin include dizziness and drowsiness. Some women also develop a rash and fluid retention. We need more research to confirm how well these drugs work and find out more about side effects.


Clonidine is a drug used for a variety of conditions, including high blood pressure. It can reduce the number of hot flushes women have but it doesn’t reduce their severity or how long they last. Unfortunately, we know from research that clonidine has not been proven to reduce hot flushes in men.

You can have clonidine as a tablet or wear a patch on your skin. Side effects include dizziness, a dry mouth, constipation, drowsiness, and difficulty sleeping.


Progestagens such as megestrol acetate (Megace) are hormones. Doctors only consider prescribing progestagens to women and men who have had a hormone dependent cancer if they have severe hot flushes and no other treatment is working. There is no long term research to show whether they are safe to take for people who have had hormone sensitive breast or prostate cancer.

Progestagens can reduce hot flushes by more than 80% and seem to work equally well in women and men. Side effects can include skin rashes, fluid retention, dizziness, a dry mouth, an increased risk of blood clots, and headaches. They can also cause vaginal discharge and vaginal bleeding (withdrawal bleeding) in women.

Hormone replacement therapy

HRT contains oestrogen. It stops hot flushes in 9 out of 10 women in the general population (90%). We know from research that in women who have had breast cancer, HRT increases the risk of the cancer coming back. So doctors don’t recommend HRT for women who have had breast cancer.

Cyproterone acetate

Cyproterone acetate reduces the amount of testosterone that the adrenal glands make in men. It can also help to reduce hot flushes. A recent French trial compared it with medroxyprogesterone and venflaxine. They found that all the drugs reduced hot flushes in men. But cyproterone and medroxyprogesterone reduced the number of hot flushes more than venflaxine.

As cyproterone is a treatment for prostate cancer it may interfere with other treatments you are having and so it is not suitable for all men.

Folic acid

Researchers are looking into folic acid as a possible treatment for post menopausal symptoms. The FOAM trial is looking at this for women who have had breast cancer or womb cancer, or women who have not had cancer. The researchers want to find out if folic acid helps to control hot flushes. They will also collect blood and urine samples to see what happens to folic acid in the body.


Cognitive behavioural therapy (CBT)

Cognitive describes the mental process that we use to remember, reason, understand, solve problems and make judgements. Behaviour describes our actions or reactions to something. Cognitive behavioural therapy (CBT) aims to help us change how we respond to certain situations or emotions. It helps us understand how our thought patterns may affect our feelings or the way our body works. The therapy teaches us how to calm our body and mind. This helps us to control our feelings, think more clearly and generally have a more positive outlook. It can also have helpful physical effects.

Researchers have tried CBT to see if it can help women who have hot flushes and sweats. One Cancer Research UK funded study found that group CBT can reduce the effect of hot flushes and night sweats for women who have had breast cancer treatment. The reductions in sweats and flushes continued after the treatment ended. It helped women to feel better, sleep better, and have a better quality of life. You can read about this study (the MENOS1 study) on our clinical trials database. 

You can ask your doctor or breast care nurse whether CBT is available in your area.


Complementary therapies for hot flushes

Researchers have looked at a number of complementary therapies as treatments for hot flushes in menopausal women. There is some information about using them after breast cancer but less for men who have prostate cancer.

Acupuncture has been researched as a treatment for hot flushes in both women and men. A small study compared acupuncture with the anti depressant venlafaxine. The treatments worked equally well at reducing hot flushes in women with breast cancer. This was only a small study and we need further research to confirm how well both treatments work.

A study looked at using auricular acupuncture in men having hormone therapy for prostate cancer. In auricular acupuncture, the practitioner puts needles or small beads (called acupressure beads) onto the outer part of the ear. They may leave them in place for a few days. 60 men took part in the study and had the acupuncture weekly for 10 weeks. In 2009, the study reported that more than 9 out of 10 men (95%) said that the flushes had reduced in severity.

Soy has been tried for hot flushes because women in Asia have fewer hot flushes than women in western countries. People in Asia tend to eat more soy than people in the West. There are mixed results from research, with some trials showing that it reduced hot flushes and others showing no difference. There is also some concern about the safety of soy for women with hormone dependent cancers because soy contains plant oestrogens. At the moment there is not enough evidence to suggest that women who have had breast cancer should take it.

Black cohosh is a native plant of North America. In Germany it is used to treat menopausal symptoms. It is thought to have oestrogen like effects on the body. Evidence from research is mixed. Some trials found that it helped to reduce hot flushes in women and others did not. But an overview of all the trial results found that it did not reduce hot flushes in women. It has not been tested in men.

Red clover is a plant that contains plant oestrogens. Some trials have found that it reduces hot flushes but others have not. There is also some concern that it could increase the risk of cancer coming back in people with hormone dependent cancers because it contains oestrogens.

Ginseng, Angelica sinensis (Dong quai) and Evening primrose oil have been looked at as treatments for hot flushes. There is currently no evidence to show that they work. 

Read more about complementary therapies and cancer.


Coping with hot flushes and sweats

It is not easy to cope with hot flushes and sweats. Understanding more about them and what you can do to help is a good starting point. If they are making it hard to sleep, try to rest during the day if you can. Tiredness can make it more difficult to cope.

Talk to your doctor or nurse if you are having problems so they can suggest treatments that you can try. You can also contact the Cancer Research UK information nurses on 0808 800 4040, from 9am to 5pm, Monday to Friday. They would be happy to help.

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Updated: 25 June 2015