What is gynecomastia?

Gynecomastia (guy-na-co-mas-tee-ah) (often socially referred to as ‘man boobs’) is when male breast tissue grows larger than usual. It’s benign, which means that it’s not cancer.

It starts as a rubbery, firm mass under the nipple, which then spreads outwards over the breast area. It usually affects both sides of the chest, but often grows in different amounts. Sometimes it only affects one side. The growing tissue can be painful or tender, and can cause men to feel anxious and embarrassed.  

You can develop gynecomastia at any age or weight, but it often arises around puberty when your hormones are changing.

Sometimes you can accumulate extra fat, not breast tissue, if you’re overweight. This isn’t the same thing as gynecomastia, and is sometimes called pseudogynecomastia.

Gynecomastia is very common. During puberty, more than half of boys will develop gynecomastia, which usually reduces in size as you get older. In later years, about one-third of men will develop gynecomastia.

Although gynecomastia is a common and normal part of puberty and ageing, it can cause emotional distress and social problems. Some people feel embarrassed or anxious about their chest, and avoid activities that involve taking their shirt off, or avoid wearing certain clothes. It can help to talk to family, friends and partners, or to a psychologist or counsellor if you’re feeling upset.

You can also talk to your doctor, who can check for underlying reasons for the gynecomastia, and if they can be treated.

What causes gynecomastia?

There are many possible causes of gynecomastia.

Sometimes, it’s just a part of the body’s normal functioning — it’s common for hormones to change throughout different stages of life. It could also be related to medication or drugs. Sometimes it’s the symptom of another condition.

During puberty, the testicles produce more oestrogen than testosterone, which can lead to gynecomastia. Usually, this type of gynecomastia goes away by itself, but sometimes it can continue for a longer time.

Later in life, your body starts to make less testosterone, which can also encourage the growth of breast tissue.

Some medications or drugs can affect the amount of oestrogen and testosterone in your body. These medications include anabolic steroids, heart medications, marijuana and alcohol, as well as medications for depression, heart problems, high blood pressure, stomach ulcers, antibiotics, chemotherapy drugs, and prostate cancer drugs.

If you stop using the drug, this will often make the gynecomastia go away. You should always talk to your doctor before stopping any medicines.

There are many different diseases or conditions that can affect the ratio of oestrogen to testosterone in your body, causing gynecomastia. These conditions are quite rare, but include genetic problems, chronic diseases such as kidney and liver disease, and tumours in the testicles or adrenal gland.

What genetic problems cause gynecomastia?

Genetic causes of gynecomastia are rare. However, the most common genetic cause is a condition known as Klinefelter syndrome.

If you have Klinefelter syndrome, you have an extra X chromosome. This means that your testicles are not producing the usual amount of testosterone.

Taking testosterone will prevent gynecomastia from happening. If you already have gynecomastia, then testosterone treatment might reduce it. Sometimes, cosmetic surgery is needed to remove any extra breast tissue that remains.

Is there a link between gynecomastia and breast cancer?

Breast cancer is very uncommon in men, with around 100 Australian men diagnosed each year (less than 1% of all breast cancers).

Breast cancer presents differently to gynecomastia. It’s usually hard and irregular, rather than soft, and usually in one side of the chest but not the other. Other symptoms might include nipple deformity or discharge, or lumps in the armpit.

Men with gynecomastia have around twice the chance of getting breast cancer, although it’s still very uncommon.

How is gynecomastia treated?

Gynecomastia can be treated with medication or surgery. Which treatment is right for you depends on the underlying cause of your gynecomastia and what your cosmetic concerns are. For many people, it’s likely that gynecomastia will go away with time.

Your doctor’s appointment

Questions to ask your doctor

  • What treatment options are available for gynecomastia?

  • Will treatment reduce the breast tissue size and soreness?

Things to think about before your appointment

  • When did you first notice a change in your breast tissue? Were the changes on one or both sides?

  • Does your chest/breast tissue feel tender or sore?

  • Have you recently had any other health problems or started any new medication?

Email these questions to yourself to take into your doctor's appointment.

Resources

Gynecomastia Fact Sheet Image Tile

Fact sheet

Gynecomastia fact sheet