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What is Gynecomastia

What is gynecomastia? Gynecomastia is defined as the atypical accumulation of breast tissue in a man, often referred to as “female-like breasts on a male.” Gynecomastia is a common male medical breast disorder and represents 65% of all male breast disorders. Gynecomastia is considered a physical disease for men. It can also affect them psychologically and socially.

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Medical Author: Miguel Delgado, M.D.

Dr. Delgado is a highly skilled surgeon specializing in gynecomastia surgery. Dr. Delgado has committed a significant amount of his practice to the care and education of men and boys with gynecomastia. Dr. Delgado’s practice philosophy is to provide the highest quality of patient care to the people who seek out his professional services. Dr. Delgado and his staff are committed to understanding their patients concerns, educating them on their options, and executing the best surgical outcome for each patient. Dr. Delgado is the new owner of Gynecomastia.org since 2010. He has dedicated a significant part of his life and practice to improving the Gynecomastia.org community.


by Miguel Delgado, M.D.

What is Gynecomastia?

What is Gynecomastia?  It comes from the Greek word for “women-like breast.” There are many terms for gynecomastia in the public domain. Although gynecomastia is the most common, the second most common is “man-boobs” or “moobs.” The muscle-building industry has a culture of using anabolic steroids, and the results are often termed “bitch tits.” The internet revolution has dramatically improved the decimation of information regarding gynecomastia. This recognition has resulted in an increased understanding of the condition, but most importantly, men now realize there is a successful treatment: male breast reduction surgery.

True Gynecomastia vs Pseudogynecomastia

Gynecomastia has a wide range of causes. In many cases, the etiology is unknown, and it can affect one side or both. True gynecomastia needs to be distinguished from pseudogynecomastia.

True Gynecomastia

In gynecomastia, breast enlargement is due to the development of breast tissue similar to that found in female breasts. It is often firm and, at times, can be tender. On occasions, the breast gland can even secrete a fluid that is similar to breast milk. The only treatment for this condition is male breast reduction surgery.




Pseudogynecomastia is due to the accumulation of fat. It is sometimes referred to as “fake gynecomastia,” and is often seen in males who are overweight. The chest size is usually proportional to the rest of the body and will fluctuate with weight gain and loss. This condition can carry the same social stigma as true gynecomastia and should not be dismissed. In obese men, a large belly with excess body weight can be socially acceptable, but for many overweight men, pseudogynecomastia presents a more significant, embarrassing problem. Weight loss can help the situation. However, liposuction can also produce a considerable improvement.

Mixed Gynecomastia

Mixed gynecomastia is a combination of both breast glands and fat. Mixed gynecomastia is a prevalent type of gynecomastia, if not the most common. However, some males who are in good shape with low body fat can still present with a mass of glandular tissue. For the most part, this is an exception rather than the rule. The proper treatment for this condition is male breast reduction surgery.

Gynecomastia Classifications

The cause of gynecomastia can be classified as either physiological or pathological. However, in many cases, the cause is unknown. The term physiological refers to the hormone changes in the body. Estrogen (a female hormone) and testosterone (the male hormone) work together in combination. There is a delicate balance between the two, and an imbalance can cause breast development in men. Pathological gynecomastia refers to the relationship between testosterone deficiency and higher levels of estrogen. Both conditions can be related to diseases associated with hormone abnormalities, various tumors, chronic diseases, chromosomal abnormalities, and familial disorders.

Physiologic Causes

Physiologic gynecomastia results from male hormone changes, resulting in an imbalance between estrogen and testosterone in the breast tissue, or an increase in the sensitivity to normal estrogen levels. The most common type is adolescent gynecomastia, sometimes referred to as pubertal gynecomastia. This condition occurs in males aged 10-16 years. The incidence is 38% in males 10-16 years old, increasing to 65% at age 14, and reducing to 14% at 16 years old. Adolescent gynecomastia often resolves itself in six months. Seventy-five percent of cases resolve in two years, and 90% resolve within three years of onset.

Pathological/Medical Causes

Some of the causes of pathological gynecomastia are medical conditions that lead to breast tissue enlargement. Some of the more common medical causes of gynecomastia are listed below:

  • Hypogonadism is a health condition in which the body does not produce an adequate amount of testosterone, the hormone responsible for male traits such as body hair and muscle mass. Some men are born with hypogonadism, while others develop it later in life due to infection or injury. Some types of male hypogonadism can be treated with testosterone replacement therapy. More information on hypogonadism can be found in the Mayo Clinic article.
  • Klinefelter syndrome. This genetic condition is found in men who have XXY sex chromosomes, and not the usual XY. This chromosomal abnormality occurs in one of every 500 males born. The characteristics of Klinefelter syndrome include small testicles, low production of testosterone, and infertility. If you are looking for information and advice about this condition, the Klinefelter Support Forum is an excellent resource.
  • Pituitary Insufficiency. Hypopituitarism is a decrease in the secretion of one or more of the eight hormones produced by the pituitary gland. The signs and symptoms of pituitary insufficiency vary depending on which of the hormones are under-secreted. The resulting low production of testosterone can cause gynecomastia. Additional valuable information can be found at Hormone.org.
  • Pituitary tumors – Prolactin-producing tumors. The most common pituitary tumor is a prolactinoma. This tumor causes the overproduction of the hormone prolactin, a hormone that helps control sexual function. In men, prolactin-producing tumors may cause gynecomastia, erectile issues or impotence, infertility, a reduction in body hair, and a low sex drive.
  • Other tumors. Tumors of the testicles or adrenal glands can secrete hormones that alter the male-female hormone balance, resulting in male breast enlargement.
  • Hyperthyroidism. The increased production of thyroxine in the thyroid gland can result in male breast enlargement.
  • Kidney failure. Nearly half the patients being treated with ongoing hemodialysis experience gynecomastia due to hormonal changes.
  • Liver failure and cirrhosis. Liver disease and related medications taken for cirrhosis are associated with gynecomastia.
  • Malnutrition and starvation. Malnutrition causes testosterone levels to decrease, yet estrogen levels remain the same, resulting in a hormone imbalance and male breast development. Gynecomastia can occur even after a nutritionally adequate diet is restored.
  • Male menopause. This a condition that affects older men usually over 60 years old. It has a set of symptoms that are tied to reduced testosterone levels and aging. It is also called andropause a form of late-onset hypogonadism and low testosterone.


If you are concerned about gynecomastia and want answers, start by speaking with a surgeon who specializes in male breast reduction surgery. This qualified expert will evaluate your medical history and conduct a proper physical exam. Often, this process can establish a cause. If it does not, then an endocrine or hormone workup will be the next step. Men with gynecomastia are sometimes concerned about breast cancer. We are always worried about a mass, but breast cancer only accounts for .02% of all cancers in men. It is uncommon and primarily seen in men over 60 years old.



Gynecomastia: Pathophysiology, Evaluation, and Management

Ruth Johnson, M. Hassan Murad

Mayo Clin 2009 Nov; 84(11): 1010–1015.

Anatomy of the Gynecomastia Tissue and Its Clinical Significance

Mordecai Blau, Ron Hazani, Daniel Hekmat

Plast Reconstr Surg Glob Open. 2016 Aug; 4(8): e854. Published online 2016 Aug 30. doi: 10.1097/GOX.0000000000000844


Frank Q. Nuttall

Mayo Clin Proc. 2010 Oct; 85(10): 961–962. doi: 10.4065/mcp.2010.0093

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The content on Gynecomastia.org is for educational purposes only. It is not intended as medical advice. It does not replace the need to meet with a physician who will accurately diagnose your condition and suggest treatment options.

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