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Reviewed by: Mary L. Gavin, MD
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What Is Gynecomastia?

Sometimes, guys develop breasts during puberty. This is called gynecomastia (pronounced: guy-nuh-ko-MAS-tee-uh). It's usually due to normal hormone changes during puberty, and almost always goes away on its own within a few months to a couple of years.

What Are the Signs & Symptoms of Gynecomastia?

Gynecomastia causes breast enlargement. It can happen in one or both breasts. Sometimes a small, rubbery lump can be felt under the nipple. The breast area might feel sore, especially in the months after gynecomastia begins.

What Causes Gynecomastia?

Puberty is the main cause of gynecomastia in adolescent boys. Hormones are chemical messengers. The ones involved in puberty can get out of balance and lead to gynecomastia.

Some medicines, drugs (including alcohol, marijuana, amphetamines, and heroin), anabolic steroids (taken to build muscle and improve strength), and other medicines also can cause gynecomastia. The herbal supplements tea tree oil and lavender oil may also lead to gynecomastia. Rarely, gynecomastia can be a sign of other medical conditions.

There's also something called pseudogynecomastia (or false gynecomastia). This has nothing to do with puberty or hormones. It's when some guys have extra fat in the chest area that makes it look like they have breasts. A health care provider's exam can tell whether a guy has gynecomastia or pseudogynecomastia.

Who Gets Gynecomastia?

About half of all guys going through puberty get gynecomastia in one or both breasts.

How Is Gynecomastia Diagnosed?

Health care providers diagnose gynecomastia by asking questions and doing an exam. Usually no other testing is needed, but sometimes blood tests are done.

How Is Gynecomastia Treated?

Gynecomastia usually goes away without medical treatment. The breasts flatten out within a few months to a couple of years.

If gynecomastia is very severe, there is medicine that can help. And if gynecomastia lasts past puberty, surgery can reduce the size of the breasts.

What Can I Do?

Even though it's just a temporary change for most teens, some guys with gynecomastia might feel embarrassed or self-conscious about their appearance. Many guys find that wearing loose-fitting shirts helps make it less noticeable until the breasts shrink.

If you have gynecomastia and it really bothers you, or has lasted more than about 2 years, talk to your health care provider about possible treatments.

Reviewed by: Mary L. Gavin, MD
Date reviewed: May 2020