Gynaecomastia affects men and boys.

The main symptom is getting bigger breasts than usual. Your nipples or breasts may also look swollen or feel sore.

1 or both breasts may be affected.

See a GP if you:

Causes of gynaecomastia can include:

• hormone changes in men aged over 50, or during puberty
• being overweight
• certain medicines
• conditions such as an overactive thyroid, kidney disease, or cirrhosis
• drug use, including anabolic steroids
• the effect of pregnancy hormones on some newborn babies

Gynaecomastia is often harmless and may not need treatment, but if it's a problem for you, your GP may recommend:

• medicines that reduce or increase certain hormones
• losing weight, if you're overweight

If your gynaecomastia is caused by a condition, getting treatment for the condition may help reduce the size of your breasts.

Surgery can reduce your breasts if other treatments have not worked, but it may not be available on the NHS.

When gynaecomastia happens in newborn babies, or when it's caused by puberty, it usually goes away by itself over time.