What is Gynecomastia? 
December 1, 2020

Gynecomastia (pronounced “guy-nuh-koh-MAS-tee-uh”) is enlargement of the breast tissue in males. It is noncancerous and a result of hormonal imbalance. 

When does it occur?

Gynecomastia can occur in both boys and men from infancy to old age.

Infant gynecomastia: Male babies may have enlarged breasts at birth, and in the months following, due to exposure to their mother’s hormones during gestation. More than half of male babies have gynecomastia. 

Adolescent gynecomastia: Hormone changes during puberty can cause gynecomastia. Adolescent gynecomastia typically affects both breasts and resolves on its own within six months to two years. 

Adult gynecomastia: One-quarter of men ages 50 to 69 have gynecomastia. In adults, it typically affects both breasts, but may first begin in one. 


Common symptoms include: 

  • Swollen breast tissue
  • Breast tenderness
  • Enlarged, rubbery, or tender areola 

Symptoms may include one or both breasts and affect breasts differently.  

Causes of Gynecomastia

Enlargement is caused by hormonal imbalance. This imbalance may be due to normal hormonal fluctuations, disease or medication. Causes outside of typical hormonal fluctuations include: 

  • Chronic liver disease, cirrhosis of the liver, or liver tumor
  • Thyroid disease
  • Infectious hepatitis 
  • Pituitary tumor
  • Chronic lung disease
  • Klinefelter’s syndrome 
  • Starvation 
  • Some medications to treat prostate, stomach and heart conditions; depression; anxiety; cancer
  • Street drugs including amphetamines, marijuana and heroin
  • Plant oils, such as tea tree or lavender 

When to see a doctor

See your doctor if the breast has a hard, distinct lump, there is nipple discharge or retraction, or one breast is enlarged. You may also want to see your doctor if you have ongoing pain, tenderness and swelling. 


Because this diagnosis comes with few complications, treatment is typically not needed. However, if symptoms persist and cause emotional stress, your doctor may look for underlying causes, including medical conditions or medications, for a resolution. In some cases, a doctor may recommend surgical removal of glandular breast tissue. 

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