Gynecomastia is the enlargement of breast tissue in men and boys. Both men and women have breast tissue, and it is found underneath the nipple on the chest wall. In most children and in adult males, the breast tissue is so small that it cannot be felt.

Breast tissue responds to hormones; oestrogen (the ‘female hormone’) causes the tissue to grow and enlarge. So, in girls going through puberty and in women (where oestrogen levels are higher) the breast tissue grows normally.

In men where levels of testosterone (the ‘male hormone’) are usually much higher than levels of oestrogen, the breast tissue does not grow, although it is still there. Enlargement of breast tissue in males is therefore unexpected, and it is called gynecomastia – or sometimes referred to as ‘gyno’.

Causes of gynecomastia

There are several causes of breast tissue enlargement in males, and it is most commonly found in babies, adolescents and in older men. Some breast enlargement in boys during puberty is extremely common, and occurs in around two thirds of teenagers.

Gynecomastia in teens is usually caused by the surge in hormones during puberty.

All people produce both oestrogen (female hormone) and androgen (male hormone). A slight imbalance in the levels of these during puberty is the most common cause of gynecomastia. It will go away on its own when the hormone levels settle down to normal.

Gynecomastia in puberty is much more common in boys who are overweight. This is because hormones are altered by fat tissue, resulting in higher levels of oestrogen – the hormone which encourages breast tissue growth.

In a very few cases, there can be other reasons for breast enlargement in teenage boys, so doctors will ask a range of questions and perform a full examination of the boy to make sure nothing is missed.

Unusual causes of gynecomastia in teenagers include:

  • Medications (including some heart medicines, those used for gastro-oesophageal reflux and some herbal skincare products);
  • Growths or tumours which secrete hormones;
  • Genetic conditions leading to low androgen levels;
  • Liver or thyroid disease.

normal breast and gynecomastia

When does gynecomastia need investigating?

As some enlargement of breast tissue occurs in up to two thirds of teenage boys, in most cases it does not need investigating.  However, there are some cases which do need checking out to make sure there is no worrying reason for the gynecomastia. These include:

  • Breast enlargement in a younger boy before other signs of puberty are seen;
  • One-sided or unilateral swelling;
  • Excessive enlargement that may be causing psychological distress;
  • Painful swelling;
  • An obvious lump within the swollen tissue, or discharge from the nipple;
  • If there are any other problems or symptoms in addition to the enlarged breast tissue.

If the boy or their family are worried about the gynecomastia, they should visit their physician for advice. The doctor will ask about the boy’s medical history and if any medications are being taken. They will then examine the boy.

This will include an examination of the breasts and armpits, as well as a general examination including the abdomen and testes. This is to ensure that there are no signs of any worrying cause for the gynecomastia. In some cases some blood tests may be recommended, or possibly an ultrasound scan of the breast tissue. Again, these are to check that there are no causes for concern.

In many boys where the cause is known – such as simple gynecomastia of puberty – no further investigation will be needed.

Natural history of gynecomastia in puberty

Gynecomastia is commonly first seen around two years after the start of puberty. In most boys it stays for one to two years before spontaneously resolving. In some boys – around 15% – gynecomastia can persist after the age of 16 years, and possibly into adulthood.

Although gynecomastia does not usually cause any symptoms, if the swelling is significant it may be tender to the touch, or uncomfortable if the area is bumped. Any other physical symptoms such as more severe pain, separate lumps within the swelling, lumps in other areas such as the armpits or testes, or fluid discharge from the nipple should be discussed with a doctor.

Having swollen breast tissue may be distressing for the teenager. Although it is very common, many boys do not realise this and may become embarrassed. It is important to reassure the teenager that it is likely to go away on its own and is unlikely to need any treatment to get rid of it.

Despite this reassurance, in some boys the distress can lead to them avoiding activities such as sports where the swelling may be noticed by others. In some cases, the distress and anxiety are so great that treatment is suggested to get rid of the swelling.

Possible treatments

In most teenagers gynecomastia does not need treatment as it will go away on its own. The boy and their family are simply advised to keep an eye on the swelling and wait for it to go away. However, where the swelling is especially large and is causing embarrassment or psychological distress, treatment may be recommended to try and get rid of the problem.

In addition, swelling which does not go away on its own after two years may need treating.

Medications may be tried, but they tend not to work as well if the swelling has lasted for longer than two years. The medicines work by altering hormone levels to encourage the body to get rid of the swollen breast tissue. In puberty, altering hormone levels may have undesirable side-effects, so this treatment may not be recommended.

Teenager gynecomastia surgery

The most common treatment to get rid of gynecomastia in puberty is surgery.

Surgery may not be suggested until the teenager is coming towards the end of puberty. If an operation is carried out any earlier, any breast tissue that is left may simply regrow following the procedure, leading to a poor outcome.

Surgery involves removing the breast tissue. This is carried out through a small incision made just underneath the nipple. It is important during surgery to remove as much of the breast tissue as possible, so that what remains does not simply grow again.

However, the surgery must also try and leave some of the normal fat tissue on the chest wall. If too much fat tissue is taken away the nipple will ‘stick’ to the chest wall, leading to a poor final appearance.

Outcomes of surgery

Surgery is carried out under general anaesthetic, which means the patient will be asleep during the surgery. What exactly needs to be done and how long the recovery time will be depends on how much tissue needs to be removed.

This should be discussed with the surgeon before the procedure. In most cases, the boy should be free to go home soon after surgery, and will recover well. If the gynecomastia was very significant, a small plastic tube may be left in the wound for a few days to drain away any fluid after the surgery.

The teenager is likely to need some painkillers for several days, and there may be stitches which need to be taken out.

The long term results of teenager gynecomastia surgery are usually good. There will be a small scar under the nipple, but usually this follows the curved line of the nipple edge and once it is healed it becomes very difficult to see.

No surgery is ever risk-free and problems or complications are always possible, although uncommon. For teenager gynecomastia surgery these include infection of the wound, pain after the procedure, regrowth of the gynecomastia and a poor cosmetic result (for example if the nipple ‘sticks’ to the chest wall and causes the skin to be pulled in).

All of these are unusual, and most teenagers have a straightforward procedure and recovery. The expected outcomes and possible problems should all be discussed with the surgeon before the procedure.


Gynecomastia in puberty is a very common occurrence, affecting around two thirds of teenagers. In most boys it will last for up to two years before going away on its own. In some boys, investigations will be needed to make sure that there are no rare causes for the breast tissue swelling.

Although the boy may be keen to find out how to get rid of the swelling, as it goes away on its own, most boys do not need treatment. Where the swelling is very problematic or long-lasting, treatment such as surgery may be suggested.

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