Causes of Gynecomastia in Men

Gynecomastia affects millions of men and can develop at almost any age. While enlarged male breast tissue is often seen as a cosmetic concern, it is frequently linked to hormonal changes, medical conditions, medications, or lifestyle factors. Understanding what causes gynecomastia in men is essential because treatment recommendations vary significantly depending on the underlying driver.

For some men, gynecomastia develops during puberty and resolves on its own. For others, it may point to low testosterone, elevated estrogen levels, thyroid disease, medication side effects, or other endocrine disorders. Dr. Kahinde Falawewo, MD, a double board-certified endocrinologist at Hilltop Internal Medicine and Endocrinology in Oxon Hill, Maryland, specializes in identifying the hormonal and metabolic root causes of male breast tissue growth. A thorough evaluation is the only reliable way to determine the cause and guide appropriate care.

 

What Is Gynecomastia?

Gynecomastia is the enlargement of glandular breast tissue in men. It differs from pseudogynecomastia, which is excess chest fat without actual glandular growth. The distinction matters clinically because true gynecomastia usually requires a medical evaluation to identify a hormonal or medical cause, while pseudogynecomastia may respond to diet and exercise alone.

Common gynecomastia symptoms include:

• Firm or rubbery tissue felt directly behind the nipple
• Swelling that may affect one or both breasts
• Tenderness or sensitivity in the breast area
• Noticeable enlargement that causes self-consciousness

The condition can develop at any age, though it is most common during adolescence and in men over 50. When it appears suddenly or progresses in adulthood, medical evaluation is necessary. According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), hormonal changes are the primary cause of gynecomastia across all age groups.

 

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Puberty and Adolescent Gynecomastia

Gynecomastia during puberty is very common, affecting between 25% and 60% of teenage boys. During adolescence, testosterone production increases rapidly, but so does aromatase activity, the enzyme responsible for converting testosterone into estrogen. This temporary mismatch can cause breast tissue growth even in otherwise healthy teens.

In most cases, adolescent gynecomastia resolves within two to three years as hormone levels stabilize. However, some teenagers experience persistent enlargement into adulthood.

A medical evaluation becomes appropriate if:

• Gynecomastia appears unusually early or late in puberty
• Enlargement is severe or causes pain
• Only one breast is affected
• The condition persists beyond ages 17 to 18
• Associated symptoms suggest a broader hormonal disorder

An endocrinologist can distinguish between normal pubertal gynecomastia and cases that require intervention.

 

The Role of Hormones in Gynecomastia

Hormonal imbalance is the primary driver behind most cases of gynecomastia. The condition develops when the ratio between testosterone and estrogen shifts in a way that allows breast tissue to grow. This estrogen and testosterone imbalance can occur from low testosterone, elevated estrogen, or both at the same time.

How Testosterone Works?

Testosterone, the primary male sex hormone, suppresses breast tissue growth. When testosterone levels fall or its effects are blocked, breast tissue can begin to enlarge.

How Estrogen Affects Male Breast Tissue?

Estrogen exists in all men at lower concentrations. When estrogen rises relative to testosterone, or when testosterone drops while estrogen stays stable, breast tissue becomes more responsive to hormonal signals and begins to grow.

The Testosterone-Estrogen Ratio

Male breast tissue growth typically results from one of four shifts in this ratio:

• Decreased testosterone production
• Increased estrogen production
• Increased conversion of testosterone into estrogen
• Reduced estrogen clearance by the liver

Identifying which of these applies to a given patient is essential because the treatment differs for each.

 

Low Testosterone (Hypogonadism) and Gynecomastia

Low testosterone, medically referred to as hypogonadism, is one of the most common endocrine causes of gynecomastia in adult men. When testosterone drops, the relative proportion of estrogen increases, which directly stimulates breast tissue growth. This is why low testosterone and gynecomastia frequently appear together.

Age-Related Testosterone Decline

Testosterone naturally decreases by approximately 1% per year after age 30. For some men, this decline accelerates, creating hormonal conditions that favor breast tissue growth.

Primary Hypogonadism

In primary hypogonadism, the testes fail to produce adequate testosterone. Common causes include:

• Testicular injury or disease
• Klinefelter syndrome
• Chemotherapy or radiation treatment
• Certain infections
• Undescended testicles

Secondary Hypogonadism

In secondary hypogonadism, the pituitary gland or hypothalamus fails to send the correct signals to the testes. This can result from:

• Pituitary tumors
• Brain injury or surgery
• Obesity
• Chronic illness
• Certain medications

Associated Symptoms

Men with hypogonadism frequently report symptoms beyond gynecomastia, including fatigue and low energy, reduced muscle mass and strength, low libido, erectile dysfunction, mood changes, and hair loss. When gynecomastia appears alongside these signs, low testosterone should be assessed through blood testing with an endocrinologist.

 

Elevated Estrogen Levels

While less commonly discussed than low testosterone, elevated estrogen is a significant hormonal cause of gynecomastia in men. Estrogen in men is produced mainly through a process called aromatization, where an enzyme called aromatase converts testosterone into estrogen.

Increased Estrogen Production

Certain conditions increase aromatase activity and estrogen production:

• Obesity (fat tissue contains high concentrations of aromatase)
• Liver disease
• Hyperthyroidism
• Certain hormone-producing tumors

Obesity-Related Hormonal Changes

Excess body fat creates a compounding problem. Fat tissue produces estrogen and increases aromatase activity at the same time. This means men with obesity often experience lower testosterone and higher estrogen simultaneously, directly promoting breast tissue growth.

Liver Dysfunction

The liver is responsible for clearing estrogen from the bloodstream. When liver function declines due to cirrhosis, hepatitis, or other liver disease, estrogen accumulates in the body and increases the risk of gynecomastia.

Hormone-Producing Conditions

Certain adrenal and testicular tumors produce hormones that elevate estrogen or suppress testosterone. These require specialized endocrine evaluation and imaging to identify.

 

What are the Medications That Can Cause Gynecomastia?

Numerous medications can trigger or worsen gynecomastia by altering hormone balance or directly affecting breast tissue. Medication review is a critical part of any gynecomastia evaluation. Common categories include:

• Blood pressure medications, including certain calcium channel blockers and spironolactone, which blocks androgen activity
• Anti-androgen medications such as finasteride and dutasteride, used for hair loss or enlarged prostate, and bicalutamide, used in prostate cancer treatment
• Some antidepressants, including tricyclic antidepressants, SSRIs, and certain antipsychotics such as risperidone
• Prostate and ulcer medications, including cimetidine
• Anabolic steroids, which cause the body to convert excess testosterone into estrogen, and when stopped, create a period where testosterone drops sharply while estrogen stays elevated
• Regular cannabis use, which may lower testosterone and increase estrogen sensitivity in some men

 

Thyroid Disorders and Gynecomastia

Thyroid disease is a commonly missed cause of gynecomastia. An overactive thyroid, or hyperthyroidism, increases aromatase activity and accelerates the conversion of testosterone into estrogen, shifting the hormone balance toward estrogen and triggering breast tissue growth. According to the National Library of Medicine (MedlinePlus), hyperthyroidism affects multiple organ systems, including the endocrine pathways that regulate sex hormones.

While hypothyroidism does not directly cause gynecomastia, it slows metabolism and contributes to weight gain, which in turn increases estrogen production through greater fat tissue and aromatase activity.

Thyroid function testing is a standard part of the gynecomastia evaluation at Hilltop Internal Medicine and Endocrinology. Treating underlying thyroid disease often improves hormonal balance and can reduce breast tissue enlargement.

 

Obesity and Weight Gain

Obesity is a major risk factor for gynecomastia because excess fat tissue fundamentally alters hormone metabolism. Fat cells produce aromatase, the enzyme that converts testosterone to estrogen. The more fat tissue present, the more aromatase activity occurs and the more testosterone gets converted.

This creates a compounding hormonal problem. Obesity raises estrogen production while simultaneously accelerating testosterone-to-estrogen conversion, producing a hormonal environment that promotes breast tissue growth.

Pseudogynecomastia vs. True Gynecomastia

It is important to distinguish between the two:

• Pseudogynecomastia: excess chest fat without glandular tissue growth
• True gynecomastia: actual glandular breast tissue development driven by hormonal changes

Many men with obesity have pseudogynecomastia, but some develop true gynecomastia from the hormonal changes obesity creates. A physical examination and, in some cases, imaging are used to differentiate the two. Weight loss can improve both conditions, but true gynecomastia may require additional hormonal evaluation and treatment.

 

Other Medical Conditions Associated With Gynecomastia

Beyond hormonal imbalances, several medical conditions raise gynecomastia risk. Proper endocrine evaluation is essential for identifying which condition is involved.

• Pituitary disorders: pituitary adenomas, particularly prolactinomas, can suppress testosterone and cause gynecomastia
• Testicular conditions: testicular cancer, injury, or disease reduces testosterone production; Klinefelter syndrome commonly causes gynecomastia
• Liver disease: cirrhosis and hepatitis impair estrogen clearance and alter hormone metabolism
• Kidney disease: chronic kidney disease affects hormone metabolism and raises estrogen while reducing testosterone
• Adrenal disorders: adrenal tumors or hyperplasia can produce excess hormones that shift the testosterone-estrogen ratio

 

When Gynecomastia May Signal an Underlying Health Issue?

While some cases are benign, certain presentations warrant prompt medical attention.

Sudden Onset in Adulthood

Gynecomastia that develops suddenly in an adult, particularly after age 50, is not normal pubertal development. It points to an underlying endocrine or medical problem that needs investigation.

Rapid Growth

Breast tissue that enlarges quickly over weeks or months may indicate a hormone-secreting tumor or an acute hormonal disorder.

Breast Pain or Tenderness

Mild discomfort can accompany gynecomastia, but severe or persistent pain warrants evaluation to rule out infection, inflammation, or malignancy.

Hormonal Symptoms

Gynecomastia accompanied by fatigue, sexual dysfunction, hair loss, mood changes, or muscle weakness suggests a systemic hormonal disorder rather than isolated breast tissue growth.

Changes in Testicular Function

Testicular shrinkage, pain, or firmness alongside gynecomastia indicates possible testicular disease and requires urgent evaluation.

 

How an Endocrinologist Diagnoses the Cause of Gynecomastia?

Accurate diagnosis requires a structured evaluation to identify the root cause rather than treating the symptom. A gynecomastia endocrinologist works through several layers of assessment.

Medical History

The evaluation explores when gynecomastia began, whether it is progressing, associated symptoms, full medication history, family history of hormonal or endocrine disease, and lifestyle factors including substance use and body weight changes.

Physical Examination

The examination confirms true gynecomastia versus pseudogynecomastia, assesses testicular size and consistency, evaluates general endocrine signs such as hair distribution and skin changes, and documents weight and body composition.

Hormone Testing

Blood tests typically measure total and free testosterone, estradiol, luteinizing hormone (LH), follicle-stimulating hormone (FSH), prolactin, and human chorionic gonadotropin (hCG).

Thyroid Testing

TSH and free T4 levels assess thyroid function, since thyroid disease frequently contributes to hormonal imbalances that drive gynecomastia.

Additional Diagnostic Evaluation

Depending on initial findings, further testing may include liver and kidney function tests, imaging studies such as ultrasound, CT, or MRI if a tumor is suspected, and testicular ultrasound if testicular disease is indicated.

This layered approach identifies the specific cause, allowing targeted treatment rather than guesswork.

 

When Should Men Seek a Medical Evaluation?

Not every case of gynecomastia requires immediate intervention, but these situations call for prompt evaluation:

• Persistent breast enlargement that has not resolved after two to three years or continues past age 18
• Gynecomastia accompanied by hormonal symptoms such as low energy, sexual dysfunction, or muscle loss
• Adult-onset gynecomastia appearing for the first time in adulthood
• Rapid progression over weeks or months
• Breast pain or tenderness that is severe or worsening
• Concerns about whether an underlying condition is present

A full endocrine evaluation either confirms that no serious condition is present or identifies a treatable cause. Either outcome gives men the information they need.

Why Choose Hilltop Internal Medicine and Endocrinology for Gynecomastia Evaluation

Gynecomastia is often treated as a cosmetic issue, but it is a medical condition that requires endocrine expertise. Dr. Kahinde Falawewo, MD, is double board-certified in Internal Medicine and Endocrinology, with fellowship training in Endocrinology, Diabetes and Metabolism from Howard University Hospital. At Hilltop Internal Medicine and Endocrinology in Oxon Hill, Maryland, the evaluation process is built around identifying the specific hormonal or medical driver before any treatment is recommended.

Thorough Endocrine Testing

Rather than assuming a cause, the practice measures testosterone, estrogen, thyroid function, and other relevant hormone markers through full blood panel evaluation. Decisions are based on data, not assumptions.

Targeted Treatment Recommendations

Once the root cause is identified, treatment is tailored to that cause. Whether gynecomastia stems from low testosterone, medication side effects, thyroid disease, or obesity-related hormonal changes, the clinical approach is different for each. A hormone specialist in Oxon Hill who understands this distinction delivers better outcomes.

Accessible, Patient-Centered Care

Hilltop Endocrinology offers both in-person and telemedicine appointments, giving men in Oxon Hill and surrounding communities access to specialized endocrine care on a schedule that works for them. The practice is open Monday through Saturday from 9:00 AM to 5:00 PM.

Schedule a Gynecomastia Evaluation at Hilltop Endocrinology

Men experiencing male breast enlargement, hormone-related symptoms, or questions about gynecomastia can get clear answers through a thorough endocrine evaluation. Rather than waiting or guessing, a structured assessment with a board-certified endocrinologist identifies the cause and outlines the most appropriate path forward.

Contact Hilltop Internal Medicine and Endocrinology in Oxon Hill, Maryland, to schedule a consultation. Call 240-752-0307 or book an appointment online. The practice is located at 6130 Oxon Hill Road, Suite 204, with dedicated parking and convenient highway access.

 

Frequently Asked Questions

What is the most common cause of gynecomastia?

Hormonal imbalance is the most common cause. In younger men, this typically involves a temporary estrogen-testosterone imbalance during puberty. In older men, age-related testosterone decline combined with increased aromatase activity, often linked to weight gain, is the most frequent driver.

Can low testosterone cause gynecomastia?

Yes. Low testosterone is a major cause of adult-onset gynecomastia. When testosterone drops, the relative amount of estrogen increases, which stimulates breast tissue growth. This is why testosterone replacement therapy sometimes improves gynecomastia in men with confirmed low testosterone.

Does gynecomastia mean estrogen is high?

Not necessarily. Gynecomastia results from an imbalance between testosterone and estrogen. This can occur from high estrogen, low testosterone, or both together. Blood testing determines which applies in any individual case.

Can thyroid problems cause gynecomastia?

Yes. Hyperthyroidism increases aromatase activity and estrogen production. Thyroid function should always be evaluated in men with gynecomastia, particularly when other thyroid symptoms such as weight loss, rapid heartbeat, or heat sensitivity are present.

Can medications cause gynecomastia?

Yes. Numerous medications alter hormone balance or directly stimulate breast tissue. Blood pressure medications, antidepressants, prostate treatments, and anti-androgen drugs are among the common categories. Any man who develops gynecomastia after starting a new medication should discuss alternatives with the prescribing physician.

Is gynecomastia always related to hormones?

Most cases are hormonal in nature, but not all. Gynecomastia can also result from direct breast tissue inflammation or, rarely, malignancy. This is why a proper medical evaluation is important rather than assuming the cause.

When should a man see a gynecomastia endocrinologist?

Men should see an endocrinologist if gynecomastia is persistent, progressing, accompanied by hormonal symptoms, or if there is any concern about an underlying medical condition. An endocrinologist specializes in diagnosing and treating the hormonal and metabolic conditions that drive gynecomastia.