Quick Answer: Gynecomastia develops when estrogen activity becomes greater relative to testosterone activity in male breast tissue. Common causes include natural hormonal changes during puberty and aging, certain medications, anabolic steroid use, low testosterone, thyroid disease, liver or kidney disease, and, less commonly, hormone-producing tumors. In some cases, no specific cause can be identified.
Gynecomastia, the enlargement of male breast tissue, can affect males of all ages. Although it is often harmless, breast enlargement can sometimes be related to medications, hormonal changes, or an underlying medical condition. Understanding the possible cause is an important first step in determining whether evaluation or treatment may be appropriate. Below, we explain the most common causes of gynecomastia and factors that can contribute to male breast enlargement.
Causes of Male Breast Enlargement
1. Natural Hormone Changes
Men can develop gynecomastia when the balance between estrogen and testosterone activity changes. These hormonal shifts commonly occur during infancy, puberty, and older age.
According to Mayo Clinic, gynecomastia caused by hormonal changes during puberty usually resolves without treatment within six months to two years, although it can persist into adulthood. It also becomes more common later in life as testosterone levels decline and other age-related factors affect hormone balance.
2. Obesity and Pseudogynecomastia
Excess body fat can cause male breast enlargement, but this is not always the same as true gynecomastia. Pseudogynecomastia occurs when excess fatty tissue accumulates in the chest without an increase in glandular breast tissue.
Obesity can also be associated with hormonal changes that may increase the likelihood of developing true gynecomastia. As a result, some men may have both excess chest fat and enlarged glandular tissue at the same time.
Weight loss may reduce the fatty component of breast enlargement, but it may not eliminate established glandular tissue. A medical evaluation can help determine whether breast enlargement is primarily caused by fat, glandular tissue, or a combination of both. Dr. Erella emphasizes an individualized approach to gynecomastia treatment, since the appropriate plan depends on each patient’s anatomy and the type of tissue involved.
3. Hypogonadism
Hypogonadism refers to conditions where the testes (male reproductive organs) produce insufficient testosterone, disrupting the body’s estrogen-to-testosterone ratio. The Endocrine Society identifies low testosterone conditions as a recognized contributor to gynecomastia, which may also be accompanied by decreased body hair, reduced muscle mass, and sexual dysfunction. Primary hypogonadism stems from testicular dysfunction, while secondary hypogonadism results from problems affecting hormonal signaling elsewhere in the body
4. Tumors
Certain tumors can produce hormones that trigger breast enlargement in men. Testicular tumors may lead to excess estrogen, directly affecting breast tissue growth. Tumors in the pituitary gland can disrupt the body’s hormonal signaling, indirectly causing gynecomastia. Additionally, treatments for hormone-sensitive cancers may induce breast enlargement, particularly in prostate cancer patients receiving androgen deprivation therapy.
5. Hyperthyroidism
Hyperthyroidism, or an overactive thyroid, can contribute to gynecomastia by altering the balance and availability of sex hormones in the body. Gynecomastia can occur in men with hyperthyroidism, including those with Graves’ disease, the most common cause of an overactive thyroid. Treating the underlying thyroid condition may improve breast enlargement over time.
6. Kidney Failure
Advanced chronic kidney disease can disrupt normal sex hormone regulation, including reduced testosterone activity and other hormonal abnormalities that may contribute to gynecomastia. Men with kidney failure may also take medications or experience nutritional changes that affect hormone balance. These factors can make breast enlargement more likely, particularly in patients with advanced renal disease.
7. Liver Failure and Cirrhosis
Liver disease, particularly cirrhosis, can contribute to gynecomastia because the liver plays an important role in the metabolism and regulation of sex hormones. When liver function becomes impaired, the balance between estrogen and androgen activity may change, promoting the development of breast tissue. Medications commonly used in people with advanced liver disease, including spironolactone, may also contribute to gynecomastia.
8. Malnutrition
Severe malnutrition can paradoxically cause breast enlargement in men due to complex hormonal disruptions. During starvation, the body’s testosterone production decreases while estrogen-to-testosterone ratios increase. When refeeding begins, temporary hormonal fluctuations can trigger breast tissue growth. Similar patterns occur in patients recovering from anorexia nervosa or those with severe weight loss and muscle wasting from chronic diseases. This form of gynecomastia typically resolves gradually with nutritional rehabilitation and the restoration of normal weight.
9. Certain Medications
Numerous medications can contribute to male breast enlargement by affecting hormone production or activity. Anti-androgens and other hormonal treatments used for prostate cancer are well-established causes, as is spironolactone, a medication commonly used for heart and blood pressure conditions. Some other medications may also be associated with gynecomastia, although the strength of evidence varies. Anabolic steroid use can also trigger breast tissue growth by disrupting the normal balance of androgens and estrogens. If you suspect a medication is contributing to gynecomastia, do not stop taking a prescription medication without first speaking with your healthcare provider.
10. Substance Use
Alcohol and some recreational drugs may contribute to gynecomastia by affecting hormone regulation or organ function. Chronic heavy alcohol use can reduce testosterone activity and may contribute indirectly through liver damage. Marijuana has historically been associated with gynecomastia, although current evidence does not establish a clear direct causal relationship. Opioids such as heroin and methadone can suppress testosterone production and may also contribute to breast enlargement.
11. Herbal Products and Oils
Some plant-derived products have been investigated for possible hormonal effects. A small number of reports have linked lavender and tea tree oils with breast development, particularly in prepubertal boys, but evidence of a direct causal relationship remains limited. Evidence linking other herbal supplements to gynecomastia is also limited, so they should not be considered established causes.
12. Idiopathic Gynecomastia
In some cases, no specific cause of gynecomastia can be identified even after an appropriate medical evaluation. This is known as idiopathic gynecomastia. Some clinical reviews estimate that roughly one-quarter of cases may fall into this category, although estimates vary between studies and patient populations.
Conditions That Can Resemble Gynecomastia
Male breast cancer does not cause gynecomastia, but some of its symptoms can resemble male breast enlargement. Gynecomastia typically causes a firm or rubbery area of tissue beneath the nipple, while male breast cancer is more likely to present as a hard or irregular lump. The American Cancer Society also identifies nipple retraction, skin dimpling, and nipple discharge as possible signs of male breast cancer.
When to See a Doctor
Evaluate breast enlargement if it develops suddenly, keeps increasing, or is accompanied by a hard or fixed lump, nipple discharge or bleeding, nipple retraction, skin changes, significant pain, or pronounced asymmetry. Men should also seek medical attention if breast enlargement occurs along with a testicular lump, swelling, or other new testicular symptoms.
Most cases of gynecomastia are benign, but a medical evaluation can help determine the cause and rule out other conditions that may require treatment.
Can Gynecomastia Be Prevented?
Not all cases of gynecomastia can be prevented. Hormonal changes during puberty and aging, certain medical conditions, and some necessary medications may cause breast enlargement regardless of lifestyle. However, reducing certain avoidable risk factors may lower the likelihood of developing gynecomastia in some cases.
Maintain a Healthy Weight
Maintaining a healthy weight can reduce excess chest fat and may help limit hormonal changes associated with obesity. However, weight management cannot prevent all forms of true gynecomastia, particularly those caused by puberty, medications, or underlying medical conditions.
Regular Exercise
Regular cardiovascular exercise and strength training can help reduce body fat, maintain a healthy weight, and improve chest appearance. However, exercise cannot reliably eliminate the glandular breast tissue associated with true gynecomastia once it has developed.
Avoid Preventable Risk Factors
Some risk factors for gynecomastia can be reduced. Avoid anabolic steroids and recreational drugs, limit excessive alcohol consumption, and maintain a healthy weight. If you take a medication associated with gynecomastia, discuss any concerns with your healthcare provider rather than stopping the medication on your own.
How Is Gynecomastia Treated?
Treatment for gynecomastia depends on the underlying cause, how long it has been present, its severity, and whether the enlargement consists mainly of glandular tissue, fat, or both. Some cases improve after an underlying medical condition or medication is addressed, while persistent glandular gynecomastia may require additional treatment, including surgery.
The Bottom Line
Gynecomastia can result from natural hormonal changes, medications, excess body fat, and underlying medical conditions. In some cases, no specific cause can be identified. Determining whether breast enlargement involves glandular tissue, excess fat, or another condition can help guide the appropriate next steps.
If you’re concerned about persistent gynecomastia, Venkata Erella, MD, FACS, can evaluate your condition and discuss whether surgical treatment may be appropriate. Contact Aspira Plastic Surgery to schedule a consultation.
