Benign breast conditions information provided by Breast Cancer Now
About this booklet

It’s normal to have questions if you have been diagnosed with, or think you have, gynaecomastia.

This booklet explains what gynaecomastia is, what causes it, and what treatments are available.

What is gynaecomastia?

Gynaecomastia is a common, benign (not cancer) condition where male breast tissue is enlarged or swollen. It mainly affects teenage boys and older men, but it can affect men at any age.

Gynaecomastia can often make teenage boys feel anxious, and they may worry about what it means for them. However, most teenage boys develop some degree of gynaecomastia. And in 9 out of 10 cases it will get better by itself over time.

Symptoms of gynaecomastia

Gynaecomastia can affect breast tissue in 1 or both sides. Symptoms include:

The breast area being tender to touch
The breast area being painful
A lump or swelling (more common behind the nipple but can occur anywhere in the breast area, upper chest or armpit)
A noticeably larger breast or breasts

True gynaecomastia is caused by an enlargement of breast tissue. This is different from pseudo-gynaecomastia, which is an increase in fatty tissue. However, gynaecomastia can be a

mixture of both true gynaecomastia and pseudo-gynaecomastia.

What causes gynaecomastia?

Puberty

Puberty in boys usually starts once you reach your teenage years, although you may notice changes when you’re as young as 10.

Until puberty, breast tissue in boys and girls develops in the same way. However, increased hormone levels during puberty affect how breast tissue continues to develop.

You may notice your breasts are tender or growing. This is because there will be times during puberty when there’s more of the hormone oestrogen than testosterone in your body. This causes breast tissue to change.

If oestrogen levels continue to be higher than testosterone levels, breast tissue will grow.

By around the age of 15, testosterone starts to settle at a constant, higher level than oestrogen. This stops the oestrogen from having any further effect on the breast tissue.

By around the age of 19, any breast tissue enlargement will usually have begun to shrink and flatten out. However, this can take some time.

Ageing

As people get older, they tend to have more body fat. This produces oestrogen.

As men get older, they also produce less testosterone. The combination of more oestrogen and less testosterone can cause the breasts to become larger.

Weight gain in later life may be particularly noticeable in the breast area, also resulting in larger breasts. You might hear this called pseudo-gynaecomastia.

Other causes

Medical conditions

Gynaecomastia can be a symptom of some medical conditions. However, in most cases gynaecomastia is unlikely to be the only symptom you have.

It’s important to see your GP, who will assess your symptoms. They may refer you to a breast clinic to have tests.

Drugs (prescribed and recreational)

Some drugs, both prescription and recreational, can cause gynaecomastia.

Several types of drugs can change the hormone balance in the body and cause gynaecomastia. These include drugs taken for:

High blood pressure
Heart conditions
Some psychiatric conditions
Stomach ulcers

Some cancer treatments (such as hormone therapies), antibiotics, recreational drugs such as cannabis and drugs taken to build up muscles (anabolic steroids) can also cause gynaecomastia.

Herbal products

Some herbal supplements and skincare products contain oestrogen. This may increase the level of oestrogen in your body or mimic the effect of oestrogen.

Once you stop using these supplements and products, the effects will stop. Eventually the swollen breast tissue will settle down.

Being overweight

Body fat produces oestrogen, and an increase in oestrogen can make breast tissue grow.

Exercise and a well-balanced diet are important for maintaining a healthy weight.

Alcohol

Drinking large amounts of alcohol causes breast tissue to grow. This is because alcohol can stimulate the liver, reducing the level of testosterone and increasing the level of oestrogen.

Sometimes it’s not possible to tell why you have developed gynaecomastia, but not knowing the cause won’t affect the treatment options.

How is gynaecomastia diagnosed?

Seeing your GP

If you’re finding having enlarged breast tissue embarrassing, or

you’re worried, see your GP.

Your GP will usually be able to confirm if you have

gynaecomastia.

Referral to a breast clinic

Occasionally your GP may refer you to a breast clinic where you’ll be seen by a specialist doctor or nurse.

At the clinic you’ll have a breast examination.

You may need to have other tests to make a definite diagnosis.

These tests can include:

A mammogram (breast x-ray)
An ultrasound scan – uses sound waves to produce an image
A fine needle aspiration (FNA) – uses a fine needle and syringe

to take a sample of cells to be looked at under a microscope

A core biopsy – uses a hollow needle to take a small sample of breast tissue to be looked at under a microscope

Because gynaecomastia can be a symptom of other conditions, your specialist may want to examine other parts of your body.

This may include your:

Neck
Abdomen (belly)
Testicles

They may also ask you to have further tests, such as a blood test.

You can read more about what to expect at a breast clinic appointment in our booklet Your breast clinic appointment.

Treatment and follow-up

Gynaecomastia does not usually need any treatment

In most cases you will not need any treatment or follow-up if you have gynaecomastia. However, it’s important to go back to your GP if your breast tissue grows larger or becomes painful, or if you have any new symptoms.

Gynaecomastia in teenage boys usually gets better by itself over time.

For some people, removing the cause of the gynaecomastia

is all that’s needed to shrink the enlarged breast tissue. This may mean changing medicines, reducing excess body weight or reducing alcohol intake.

Occasionally people may need to have drug treatments or, very rarely, surgery.

Drug treatments

Your specialist may prescribe you drugs to treat gynaecomastia. These are:

Tamoxifen
Aromatase inhibitors (although these are prescribed very occasionally)

Not all these treatments are licensed for use in gynaecomastia. However, they have been shown to be useful in treating it. Your specialist will want you to have regular follow-up appointments if you’re prescribed any of these.

There are no guidelines on which treatment should be considered first. You may experience side effects when taking any of the drugs listed.

Your gynaecomastia may return once you stop taking these drugs. If this happens, you may want to go back to your specialist.

Tamoxifen

Tamoxifen is usually given as a treatment for breast cancer. However, studies have shown that it’s also effective in treating painful gynaecomastia.

Tamoxifen works by lowering the amount of oestrogen in the body. In men, this reduces the size of the breast tissue.

You can take tamoxifen as a tablet. Your specialist will advise you what dose to take and for how long.

Tamoxifen can have several side effects, including hot flushes and loss of sex drive (libido). You may find it useful to read our Tamoxifen booklet for more general information about its

side effects.

Aromatase inhibitors

Aromatase inhibitors are drugs used as a treatment for breast cancer. Some research suggests they may be effective in treating gynaecomastia, but more research is needed.

You can take aromatase inhibitors as a tablet. Your specialist will tell you what dose to take and for how long.

Aromatase inhibitors can have side effects such as joint pain and reduced bone strength. However, these side effects may depend on how long you take aromatase inhibitors for.

You may find it useful to read our individual aromatase inhibitors (anastrozole, exemestane and letrozole) booklets for more general information about the drugs and their side effects.

Surgery

Surgery for gynaecomastia may be recommended in exceptional circumstances. It’s not available on the NHS and will most likely need an Individual Funding Request (IFR), which is an application your specialist or GP can make for you.

Surgery for gynaecomastia is not straightforward. The type of operation will depend on the extent of your gynaecomastia and the amount of excess skin you have.

The aim of surgery is to remove excess breast tissue. Sometimes this may involve more than 1 operation.

Your breast surgeon will assess you before deciding on the most appropriate operation for you.

Liposuction (a surgical procedure where fat is removed from the affected area) is one of the most common procedures.

It can be a treatment by itself or used at the same time as a breast reduction operation, sometimes known as a reduction mammoplasty. A breast reduction operation can also be done without liposuction.

Because these procedures leave some breast tissue, your gynaecomastia could still return.

How you may feel

If you are going through puberty and coping with other physical

changes, you may find it particularly hard to discuss growing or painful breasts with anyone. This means teenage boys often don’t realise how common gynaecomastia is.

Older men may worry that the changes to their breast tissue is a sign of cancer. Having gynaecomastia does not increase your risk of developing breast cancer, but it’s still important to be breast aware. Go back to your GP if you notice any other changes, regardless of how soon these occur after your diagnosis of gynaecomastia.

You can find out more about being breast aware in our booklet Know your breasts: a guide to breast awareness and screening. Although this booklet is mainly aimed at women, the signs and symptoms to look out for are very similar.

Further support

If you have any questions about gynaecomastia or just want to talk things through, you can call our helpline on 0808 800 6000 and speak with one of our team.

AbOuT ThIS bOOklET

Gynaecomastia was wriGen by Breast Cancer Now’s clinical specialists, and reviewed by healthcare professionals and people affected by breast conditions.

For a full list of the sources we used to research it: Email health-info@breastcancernow.org

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information and support from professionals in your healthcare team. So far as is permiGed by law, Breast Cancer Now doesn’t accept liability in relation to the use of any information contained in this publication, or third-party information included or referred to in it.

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