✍️ What Causes Gynecomastia

The Medical Definition: Gynecomastia is defined clinically as an enlargement of male breast tissue, characterized by the presence of a rubbery or firm mass extending in a diffuse and concentric fashion under the nipple and areola.

The Common Man’s Definition: Chest fat, Male Boobs, MOOBS, Male Breast, etc

It’s common in my practice to have a patient come in saying that he has a lot of chest fat and wants it sorted. Most of these people are usually quite fit and don’t even have a lot of fat anywhere in the body, to begin with. Many would have worked out endlessly only to notice that the chest bulge hasn’t reduced. If anything the ‘chest fat’ is now more prominent and protruding than it was when they were less fit. Many men who do not research or take a medical opinion to attribute this to ‘stubborn fat’. Only when a doctor examines and points out the differences in how the ‘chest fat’ feels as opposed to the fat elsewhere do they realize that it’s something else. Some people actually feel crestfallen when confronted by the diagnosis. But nonetheless, the treatment is not too different than what they would have imagined if it was indeed fat.

When a male breast is seen under a microscope it contains what we call ‘a benign proliferation of glandular male breast tissue’. It actually means that the tissue is very similar to female breast structurally, but of course, is different functionally. It means that it serves no function in males and is a vestigial and purposeless tissue. 

During puberty, changes in the breast bud occur due to the hormonal influence and lead to transient enlargement of the breasts and is a very common occurrence. It becomes an issue when this enlargement either becomes too excessive or fails to regress in time. The emotional impact that can result during these very important formative years can have long-lasting effects on the emotional and social development of the individual. 

Male breast development occurs in a similar fashion to female breast development. At puberty in the female, complex hormonal interplay occurs resulting in growth and maturation of the adult female breast.

Gynecomastia normally can occur during three phases of life. The first occurs shortly after birth in both males and females. This is caused by the high levels of predominantly feminine hormones; estradiol and progesterone produced by the mother during pregnancy, which stimulates newborn breast tissue. It can persist for several weeks after birth.

Puberty is the second situation in which gynecomastia can occur physiologically. This again is due o the imbalance of hormones. It may be due to either decreased production of androgens (male hormones)  or change in its ratio with respect to the female hormones.

The third age range in which gynecomastia is frequently seen is during older age (>60 years). Although the exact mechanisms by which this can occur have not been fully clear, it may result from reduced male hormone production associated with aging and other factors.

In early fetal (when the baby is still in the mother’s womb) life, epithelial cells (Cells on the skin surface) that are destined to become areola also form the ducts. The ducts form the supply pipelines from where the mother’s milk is produced in the alveolar structures (the milk-producing part of the breast) glands up to the nipple. As the influence of the mother’s hormones that are transferred to the baby while in the womb reduces, the breast development ceases. This process of multiplication and tissue replication restarts when the hormonal balance is altered like in puberty. But once the hormonal issues regress, the tissue also tends to reduce when it’s not large enough. But in many men, even after the hormonal influence ceases, the gland still persists and leads to all the issues at hand.

In puberty when the gland develops and gets noticeable, many complain of pain and tenderness which sometimes leads them to medical consultation. Evaluation under the guidance of a physician can be performed as needed to rule out other conditions that can result in hormonal imbalance having an effect on the breast. Although it is reasonable to simply observe patients who present with gynecomastia even until the age of 16 or 18, when social behaviors begin to become negatively affected by the condition, it is recommended to proceed with surgical correction nonetheless. 

But most patients, however, tide over the issues during puberty and come for consultation when they are independent and employed. Most Indians, come to a doctor when they are looking for alliances or during a relationship. 

The causes of gynecomastia can be broadly classified into two categories: primary and secondary. 

Primary or idiopathic or physiological is the commoner type. It is seen in up to 90% of newborns due to the transfer of hormones from the mother. Newborn gynecomastia usually resolves spontaneously within four weeks of birth. Children with symptoms that persist after their first birthday should be examined further; they may be at risk of persistent pubertal gynecomastia. It is, however, important to rule out other causes while confronted with adolescent gynecomastia.

Secondary or non-physiological gynecomastia occurs due to a plethora of etiologies and requires thorough clinical and laboratory assessment

Causes of secondary gynecomastia

1. Mediation or drug abuse

   Hormones: Androgens, anabolic steroids, estrogens, estrogen agonists, and hCG

   Antiandrogens/ Bicalutamide, flutamide, nilutamide, cyproterone, and GRH  agonists       (leuprolide and goserelin)

   Antibiotics: Metronidazole, ketoconazole,b minocycline, isoniazid

   Antiulcer medications: Cimetidine,b ranitidine, and omeprazole

   Chemotherapeutic: Methotrexate, alkylating agents, and vinca agents alkaloids

   Cardiovascular drugs: Digoxin,b ACEIs (eg, captopril and enalapril), calcium channel blockers (diltiazem, nifedipine, verapamil), amiodarone, methyldopa, spironolactone, reserpine, and    minoxidil

   Psychoactive agents: Anxiolytic agents (eg, diazepam), tricyclic antidepressants,    phenothiazines, haloperidol, and atypical antipsychotic agents


   Antiretroviral therapy for HIV, metoclopramide, penicillamine, phenytoin, sulindac, and


2. Liver disorders like Cirrhosis

3. Hormonal issues: 

 3a. Primary hypogonadism 

   5α-reductase deficiency 

   Androgen insensitivity syndrome 

   Congenital anorchia 


   Klinefelter syndrome 

   Testicular torsion 

   Testicular trauma 

   Viral orchitis

3b. Hormone producing Tumors 

   Adrenal tumors 

   Gastric carcinoma producing hCG 

   Large cell lung cancer-producing hCG 

   Pituitary tumors 

   Renal cell carcinoma producing hCG 

   Testicular tumors, particularly Leydig or Sertoli cell tumors 

3c. Secondary hypogonadism 

3d. Kallmann syndrome 

4. Thyroid gland disorders like Hyperthyroidism 

5. Kidney disorders like Chronic renal insufficiency 

6. Other rare causes 

   Familial gynecomastia 

   Human immunodeficiency virus 

   Malnutrition and disorders of impaired absorption (e.g., ulcerative colitis, cystic fibrosis)