What is Gynecomastia?

Gynecomastia is a condition of overdevelopment or enlargement of the breast tissue in men or boys. The breasts become larger. They may grow unevenly.

Gynecomastia often happens when a preteen or teenage boy is going through the hormonal changes of puberty. But it can also happen to newborn babies and to men as they age.

Continue reading to learn more about Gynecomastia and its causes, or contact our Sydney clinic to make an appointment.

What causes gynecomastia?

Gynecomastia is usually a benign (non-cancerous) condition which may be linked to a number of different causes of hormone changes. In many cases, the cause isn’t known.

Gynecomastia is often caused by changes in levels of the female hormone (estrogen) and the male hormone (testosterone), but can be caused by other factors.

Gynecomastia can be a side effect of certain medicines, such as antidepressants, antibiotics, chemotherapy, prostate cancer medicines, ulcer or cardiovascular medicines. Illegal drugs, such as anabolic steroids, heroin, or marijuana can also cause gynecomastia.

Diseases and Conditions

Some diseases and medical conditions may also cause gynecomastia. These include:

  • Thyroid disorders
  • Injury or trauma
  • Obesity
  • Liver diseases
  • Kidney disease
  • Some conditions that a baby is born with (congenital disorders)
  • Tumors of the adrenal glands or pituitary gland
  • Cancer (although this is extremely rare to trigger gynecomastia)

What Causes Gynecomastia in Puberty?

Gynecomastia in puberty occurs when there’s an imbalance between the male hormones (known as androgens) and female hormones (estrogens) that naturally occur in the body. As a result of surging hormones during puberty, up to half of all teenage boys can be affected. Fortunately, Pubertal Gynecomastia is only temporary, with breast tissue usually flattening out within a few months or years.

Which Drugs Can Cause Gynecomastia?

Gynecomastia can be a side effect of certain medicines, such as antidepressants, antibiotics, chemotherapy, prostate cancer medicines, and ulcer or cardiovascular medicines. Illegal drugs such as anabolic steroids, heroin, or marijuana can also cause Gynecomastia.

Is Gynecomastia Permanent?

No, Gynecomastia is usually not permanent. In many cases, excess breast tissue can reduce over time as hormones change and fluctuate, particularly in cases brought on by puberty. For cases that occur later in life, surgery is available to reduce breast tissue.

How Long Does Gynecomastia Last For?

In puberty, Gynecomastia can last until the late teens or early 20s. For other cases, Gynecomastia may be reduced by identifying and remedying the cause (e.g. stopping a medication), however sometimes the condition does not go away on its own and surgery is required.

Is Gynecomastia Painful?

Yes, Gynecomastia can be a painful condition for some sufferers, with the swelling and growth of breast tissue often causing pain and tenderness.

The good news?

Gynecomastia is not linked to breast cancer. It is rare that men get breast cancer.

Less than one percent of all breast cancer cases develop in men, and only one in a thousand men will ever be diagnosed with breast cancer. Breast cancer in men is usually detected as a hard lump underneath the nipple and areola.[1] 

3 stages of Gynecomastia

In a published Paper ‘Gynecomastia in Adolescent Men’ (Lemain, Cayci, Simmons and Petty 2013) the following 3 stages of the condition were noted which generally correspond to hormonal change:


The first peak is found during the neonatal period, when an estimated 60 to 90% of infants develop transient palpable breast tissue because of the transplacental passage of estrogens.

This condition almost always resolves without intervention within the first year of life.


The second peak occurs during puberty, when an incidence range of anywhere between 4 to 69% of palpable breast tissue and an increase in breast size has been reported.

Often evident from the age of 10 and with a peak at age of 13-14  Gynecomastia may, followed by a decline of incidence in late teenage years.

By age 17, only 10% of boys are found to have persistent gynecomastia. In the largest cross-sectional study performed to date on gynecomastia in adolescents, the prevalence was found to be 4% in males aged 10 to 19 years. 

At this point, if the condition persist and is a concern to the patient, a surgical solution can be considered. If this applies to you or someone close to you, a consultation is the first step.


The third and last peak of occurrence is found later in life, with the highest prevalence among adults between the ages of 50 and 80 years. 

[1] REF: www.nationalbreastcancer.org/male-breast-cancer

Learn More Today

For more information about Gynecomastia, its causes and its available treatments, contact Macquarie Cosmetic Medicine today. Our Sydney clinic offers multiple options for male breast reduction.

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