What Is Gynecomastia? Symptoms, Causes, and Treatment

Gynecomastia is abnormal enlargement of breast tissue in males. It is commonly known as “male breast enlargement.” The condition is usually benign, meaning noncancerous, but it can alter physical appearance and affect self-confidence. Although it can occur at any age, gynecomastia is particularly common in newborn babies, adolescents , and older men. Research suggests that nearly half of adolescent boys may experience temporary gynecomastia. Later in life, hormonal changes may cause noticeable breast enlargement in one in three men. This article answers questions about what gynecomastia is, its symptoms and causes, how it is treated, and whether gynecomastia causes cancer .

The illustration below explains the abnormal growth of male breast tissue known as gynecomastia. The drawing on the left compares a normal chest with one affected by gynecomastia, while the detailed cross-section in the middle shows the internal structure of enlarged breast tissue. The photograph on the right shows the physical appearance of a person with gynecomastia.

What Is Gynecomastia?

Gynecomastia is benign enlargement of the breast glands in boys or adult men. The term combines the Greek words “gyne” (woman) and “mastos” (breast) . It may give the male chest a feminine appearance. Gynecomastia can be unilateral, affecting one breast, or bilateral, affecting both.

Rather than being a disease in itself, gynecomastia can also be a sign of another condition . Gynecomastia during adolescence, in particular, is considered physiological —part of normal development—and resolves spontaneously within a few years in the vast majority of cases. Breast swelling in newborns caused by maternal hormones generally disappears within a few weeks. Changes in hormonal balance contribute to gynecomastia in older men.

In summary, gynecomastia is not life-threatening and usually poses no serious health risk. Rarely, however, it may signal an underlying illness or cause psychological difficulties such as lost confidence, embarrassment, or social avoidance. Understanding its cause and treating it when necessary are therefore important.

What Causes Gynecomastia?

Hormonal imbalance is the most important cause of gynecomastia. The male body also contains small amounts of estrogen (a female sex hormone) , and the female body also contains testosterone (a male sex hormone) . Normally, testosterone predominates in men, preventing prominent breast development. However, a relative increase in estrogen levels or increased sensitivity of breast tissue to estrogen can enlarge the breast glands.

The main contributing factors can be summarized as follows:

• Physiological Hormonal Changes: During the newborn period, estrogen transferred from the mother can cause temporary breast swelling in male babies. During adolescence, hormonal fluctuations may cause gynecomastia in 50-60% of boys; it usually resolves spontaneously within 6 months–2 years. In older age, declining testosterone and increased body fat strengthen estrogen's relative effect. Gynecomastia may be found in approximately 25-30% of men aged 50-69.

• Medicines and Chemical Substances: Gynecomastia may occur as a side effect of certain medicines. Examples include hormonal medicines (antiandrogen treatments for prostate cancer, anabolic steroids, and testosterone derivatives), some antidepressants, antipsychotics, heart medicines (such as digitalis glycosides), medicines for stomach ulcers , and chemotherapy agents. These can cause breast tissue enlargement. Other possible contributors include alcohol and recreational drugs such as cannabis, heroin, and amphetamines.

• Endocrine and Metabolic Diseases: Diseases affecting hormones can cause male breast enlargement. For example, hypogonadism (deficient male sex hormones), hyperthyroidism (excess thyroid hormones), pituitary tumors, adrenal tumors , or testicular tumors may cause hormonal imbalances that lead to gynecomastia. Chronic diseases such as liver cirrhosis and chronic kidney failure can also alter hormone metabolism and enlarge breast tissue. Malnutrition and prolonged starvation may disrupt hormone balance, with an increase in estrogen during refeeding.

• Obesity: Excess weight increases body fat in men, both depositing fat in the chest and accelerating the conversion of testosterone to estrogen within fatty tissue. Breast enlargement is therefore common in overweight men. If enlargement is caused solely by fat accumulation, it is called pseudogynecomastia . In pseudogynecomastia, glandular breast tissue is not increased; the breasts are soft and generally painless. Weight loss and regular exercise can markedly improve or completely resolve pseudogynecomastia. In true gynecomastia, however, enlarged glandular tissue means that losing weight alone may not solve the problem.

In addition to these causes, a substantial proportion of cases may have no identifiable cause . These are called idiopathic gynecomastia . Temporary adolescent gynecomastia and breast enlargement in young adults, in particular, may occur without any underlying disease being found.

Types of gynecomastia: Gynecomastia can be divided into three types according to the predominant tissue:

• Glandular type: Firm tissue enlargement caused by growth of the breast (milk) glands predominates.
• Fatty type: Increased fat in the breast area predominates; pseudogynecomastia belongs to this group.
• Mixed type: Both glandular and fatty tissue are increased. This is the most common type.

Identifying the cause matters for treatment planning. Particularly when enlargement develops after middle age as a unilateral, hard, irregular mass, the doctor will perform tests to rule out a serious underlying condition. These may include blood tests to measure hormone levels, imaging such as ultrasound or mammography , and, in suspicious cases, a biopsy if needed. In most cases, a physical examination and medical history are sufficient for diagnosis.

How Common Is Gynecomastia?

Gynecomastia is more common than many people realize. The table below summarizes its frequency in males of different ages:

Table: Gynecomastia is common across different age groups. Enlargement in newborns and adolescents usually resolves after a short time. In older age, hormonal changes may increase its frequency again. Although its exact prevalence in adults is unknown, around 10-20% of men may experience some breast enlargement.

What Are the Symptoms of Gynecomastia?

Symptoms of male breast enlargement usually begin with changes in appearance. The most common include:

• Increased breast size and volume: One or both breasts become larger than usual. Enlargement may be symmetrical or more pronounced on one side.
• Palpable breast tissue: A rubbery, round-edged mass may be felt beneath the nipple. This is generally characteristic of gynecomastia and lies beneath the areola (the area around the nipple) .
• Breast tenderness or pain: Enlarged breast tissue may be tender to touch, and some patients report mild pain or fullness. Tenderness is especially common in rapidly growing tissue during adolescence.
• Nipple sensitivity: Contact with clothing may be uncomfortable, and nipple sensitivity may increase.
• Nipple discharge: Rarely, a milky or clear fluid may discharge from the nipple in gynecomastia. This occurs more often when hormonal imbalance is pronounced.
• Swollen underarm lymph nodes: Although uncommon, enlarged underarm lymph nodes may accompany changes in the breast.

Symptom severity varies. Some men have only mild fullness, whereas others have marked enlargement resembling female breasts. Choosing clothes may become difficult, and a person may avoid tight T-shirts or undressing at the beach or pool. Embarrassment and anxiety related to these physical changes are important aspects of the psychological impact of gynecomastia.

When Should You See a Doctor?

If you notice any hard lump, unilateral irregular swelling, skin dimpling, or bloody nipple discharge in the breast area, you should see a doctor. Gynecomastia usually produces soft, well-defined enlargement, whereas male breast cancer , although very rare, can cause a hard, unilateral mass with irregular edges and nipple distortion or retraction. Breast self-examination and seeking medical care for unusual findings are therefore important for early diagnosis.

If you have symptoms of gynecomastia, you may initially consult a general surgeon or plastic surgeon . The doctor assesses the nature of the enlargement by physical examination and may order tests to determine whether it is straightforward gynecomastia or related to another problem.

Treating Gynecomastia: How Does It Resolve?

Most cases of gynecomastia have the potential to resolve spontaneously or improve when the underlying cause is treated. Treatment is therefore individualized according to the cause, duration, and degree of discomfort.

1. Monitoring and Spontaneous Resolution: Adolescent gynecomastia generally does not require immediate treatment. The doctor may arrange regular visits to monitor breast tissue growth. In most young patients, it resolves spontaneously within 1-2 years. Similarly, breast swelling in newborns disappears within a few weeks. If gynecomastia is not severe and the patient can tolerate it, particularly during the first 6-12 months, observation may be recommended.

2. Treating the Underlying Cause: If a specific cause is identified, treatment first targets that cause. For example:

• If a hormonal disorder such as low testosterone or excess thyroid hormone is found, the relevant hormone treatment is adjusted.
• If the patient is taking a medicine that may cause gynecomastia , stopping it or switching to an alternative may be considered under medical supervision.
• If liver or kidney disease is present, breast enlargement may regress as the disease is treated.
• If a tumor or mass is identified as the cause, appropriate cancer treatments, such as surgery or chemotherapy, are planned.

Once the underlying cause is corrected, breast tissue generally begins to shrink over time. However, in longstanding gynecomastia, glandular tissue may become fibrotic and fail to regress completely.

3. Medication (Medical Treatment): Medication may be tried in certain cases, particularly when gynecomastia has developed within the first 1-2 years and is very distressing. The aim is to reduce breast tissue's response to estrogen or restore hormonal balance. The main medicines used include:

• Tamoxifen and raloxifene , which are SERMs (selective estrogen receptor modulators). Although primarily used to treat breast cancer in women, they may also shrink gynecomastia by reducing estrogen's effect on breast tissue. They may be used particularly for painful gynecomastia.
• Clonifen Citrate: It aims to restore balance by stimulating testosterone production.
• Aromatase Inhibitors (such as Anastrozole): These work by preventing the conversion of testosterone to estrogen.

Although medical treatments offer partial benefit to some patients, they may not provide a definitive solution in every case. They can also cause side effects, such as an increased clotting risk and hot flashes with tamoxifen. The doctor should therefore decide whether medication is needed according to severity and the patient's circumstances. In general, medicines are used to support treatment or produce early shrinkage rather than as an alternative to surgery.

4. Surgery: For gynecomastia that persists, is markedly enlarged, or causes significant cosmetic or psychological distress, surgery is the most definitive treatment. Excess breast tissue and, when necessary, fatty tissue are removed to restore a flat, masculine chest contour. Surgical treatment is discussed in detail below.

How Is Gynecomastia Surgery Performed?

Gynecomastia surgery is a type of male breast reduction. It is generally performed by specialists in plastic, reconstructive, and aesthetic surgery . The technique depends on the type and severity of gynecomastia:

• If enlargement is mainly due to increased fatty tissue , as in the fatty type or a fat-predominant mixed type, treatment with liposuction (fat removal) alone may be possible. Thin tubes called cannulas are inserted through small incisions to remove fat by suction, eliminating excess chest fat without an obvious external scar.

• If glandular breast tissue is significantly enlarged, as in the glandular type or a gland-predominant mixed type, surgical excision (removal) may be needed. The enlarged glandular tissue is removed through a small semicircular incision along the lower edge of the nipple area. Because the incision usually follows the edge of the darker areola, the scar becomes inconspicuous after healing.

• In many cases, the best result is achieved with a combination of liposuction and surgical excision . Fat is removed by liposuction, while firm glandular tissue is taken out through a small incision. This combined approach gives the chest wall a flat, smooth contour.

• Severe gynecomastia (Grade 3-4) may also involve sagging skin. With very large, drooping breasts, excess skin may be removed and nipple position adjusted if necessary. The incisions may then be somewhat larger, but cases of this severity account for only a small proportion of patients.

The Surgical Process: Gynecomastia surgery is generally performed under general anesthesia and takes approximately 1-2 hours, depending on complexity. The patient may return home the same day or stay in hospital for 1 night. Mild chest pain, swelling, and bruising during the first few days are normal. The doctor will prescribe pain relievers and antibiotics if needed.

After surgery, the patient is asked to wear a special garment for 4-6 weeks, known as a gynecomastia compression garment . This medical garment protects the surgical area from external impacts and helps the skin conform to the new contour. A return to office work may be possible within the first week, but strenuous sports and physical activity should be avoided for approximately 1 month. Because the incisions are small, the suture sites generally heal within 7-10 days, and scars fade over time.

Gynecomastia surgery has a low risk and a high success rate. Complications such as infection, a collection of blood (hematoma), or asymmetry are uncommon, and most can be prevented with appropriate surgical technique and care. The great majority of patients are satisfied and report substantial improvements in body image and self-confidence.

Are the results permanent? Yes, removed glandular breast tissue does not grow back. However, weight gain after surgery may enlarge the remaining fat cells, causing some renewed breast fullness. In addition, resuming medicines that cause hormonal imbalance or using anabolic steroids may cause gynecomastia again. Maintaining an ideal weight and avoiding contributing factors whenever possible are therefore recommended to sustain the best results.

Does Gynecomastia Cause Cancer?

No. Gynecomastia itself does not become cancerous or directly cause cancer. Gynecomastia is benign tissue enlargement within the breast, whereas cancer is uncontrolled malignant cell growth. These are different processes. The enlarged tissue in male gynecomastia generally has a benign structure described as fibroadenomatous and does not undergo malignant transformation.

However, because this is a major concern for men with gynecomastia, several points should be clarified:

• Gynecomastia and breast cancer have different symptoms: Gynecomastia usually causes bilateral, symmetrical enlargement that feels soft or rubbery and may be painful or tender. Male breast cancer is extremely rare, accounting for less than 1% of all cancers in men. When it occurs, it usually presents as a unilateral, hard, painless mass with irregular borders. Nipple retraction, distortion, and discharge, particularly bloody discharge, may also occur. These findings are not expected in gynecomastia. A man with gynecomastia-related enlargement and no such findings on examination therefore most likely does not have a malignant condition.

• Gynecomastia may very slightly increase cancer risk: Some research suggests a slightly higher rate of breast cancer in men with longstanding gynecomastia than in men of the same age without it. The likely explanation is that the underlying hormonal environment may predispose to both gynecomastia and a very small risk of breast cancer. The key point, however, is that male breast cancer is already very rare. Even in a man with gynecomastia, the chance of developing it is very low. Lifetime risk in the general male population is approximately 0.1%; even if gynecomastia increases it somewhat, it remains low.

• The underlying cause may matter: In some patients, gynecomastia may be the first sign of an estrogen-producing tumor, such as a testicular tumor. In that situation, cancer has caused gynecomastia, rather than the reverse. Ruling out a serious underlying cause is therefore important. Your doctor will use an examination and tests to confirm that the condition is harmless.

In conclusion, most patients with gynecomastia do not have cancer, and gynecomastia itself does not cause breast cancer. Nevertheless, any hardness, asymmetry, or suspicious breast finding warrants medical attention. The doctor may use ultrasound or mammography when needed to investigate a man diagnosed with gynecomastia. Do not hesitate to share your concerns with your doctor for reassurance.

Prostate Cancer Treatment and Gynecomastia

Gynecomastia means benign enlargement of male breast tissue. It may develop in some men receiving prostate cancer treatment, particularly as a result of hormone-suppressing treatments (androgen deprivation therapy, ADT). Alongside physical changes, it can create psychological difficulties. The following sections explain the relationship with prostate cancer treatment and the management of this side effect.

How Do Hormone-Suppressing Treatments Cause Gynecomastia?

Because prostate cancer generally grows under the influence of testosterone , treatment uses medicines that reduce its effects. These treatments, within ADT, either greatly reduce testosterone production or block androgen receptors to prevent testosterone from acting on cancer cells. As testosterone levels decline, the body's hormonal balance changes. The relative influence of estrogen , normally present in small amounts in men, increases and may stimulate breast tissue growth. In short, greater estrogen dominance resulting from testosterone suppression or blockade leads to breast tissue enlargement and gynecomastia.

Prostate Cancer Medicines and Gynecomastia Risk

Some hormonal treatments used for prostate cancer may increase the risk of gynecomastia:

• Antiandrogens: Oral medicines such as bicalutamide (Casodex) and flutamide are antiandrogens commonly used for prostate cancer. They block testosterone's effects throughout the body, particularly in cancer cells. However, hormonal feedback may temporarily increase testosterone production and consequently estrogen levels. This greatly increases the likelihood of gynecomastia in men taking antiandrogens. Gynecomastia and/or breast tenderness may occur in up to 70% of patients taking bicalutamide or flutamide. Breast enlargement is particularly common with long-term bicalutamide use, and one clinical trial found gynecomastia in approximately 70% of men receiving it.

• LHRH Agonists (GnRH Analogs): Injected medicines such as leuprorelin (Lupron, Prostap) or goserelin (Zoladex) stop testosterone production in the testes, a method also known medically as chemical castration . These potent hormone-suppressing treatments may also cause gynecomastia in some patients. However, with GnRH analogs , it occurs less frequently than with antiandrogens. For example, noticeable breast enlargement has been reported in only approximately 5–15% of men receiving leuprorelin or goserelin. Thus, although all hormonal treatments carry a risk of gynecomastia, the highest risk is generally associated with antiandrogens.

Preventing and Treating Gynecomastia During Prostate Cancer Treatment

If gynecomastia during prostate cancer treatment causes pain or impairs quality of life, several methods can prevent or treat it. Doctors may proactively reduce its risk as part of the treatment plan.

The main approaches include:

• Tamoxifen: Tamoxifen is a selective estrogen receptor modulator (SERM) that blocks estrogen's effects on breast tissue. It has been shown to be among the most effective treatments for gynecomastia. Studies suggest that in men receiving hormonal treatment for prostate cancer, particularly bicalutamide, tamoxifen can prevent breast enlargement or reduce existing enlargement and pain. Some studies have even reported better prevention than with radiotherapy. It is generally used at daily doses of 10–20 mg. Although it may cause side effects such as hot flashes, and possible long-term effects on prostate cancer treatment efficacy remain unclear, it is frequently used as a reliable option for gynecomastia.

• Aromatase Inhibitors: Medicines such as anastrozole are aromatase inhibitors that lower estrogen levels by blocking androgen conversion to estrogen. They have theoretically been considered useful for prevention. Clinical trials, however, found them substantially less effective than tamoxifen for antiandrogen-related gynecomastia. For example, preventive anastrozole showed no clear benefit over placebo and was much less successful than tamoxifen. Although tried in some cases, aromatase inhibitors are therefore generally not recommended as a first choice for prevention or treatment.

• Radiotherapy: Low-dose radiotherapy to the chest before hormonal treatment may help prevent gynecomastia. A small preventive radiation dose is delivered to glandular breast tissue, a technique called “breast bud radiotherapy.” For example, 1–2 low-dose sessions at the start of hormonal treatment may significantly reduce the risk of gynecomastia and associated pain. Radiotherapy is generally preventive; once marked enlargement is established, it may relieve pain but may not sufficiently shrink the tissue on its own. Although the very low dose makes the risk minimal, a second cancer could theoretically develop years later in the treated area. The decision should therefore be discussed with the patient, weighing benefits and risks.

• Surgery: If gynecomastia is severe and cannot be controlled with medicines or radiotherapy, surgery may be an option. Excess breast tissue is surgically removed in a male breast reduction operation. A plastic or general surgeon usually removes enlarged glandular and fatty tissue through an incision around the nipple area to flatten the chest. Surgery can provide a permanent solution but carries risks like any operation. Rare complications include bleeding, infection, nipple distortion such as inversion or flattening, and loss of sensation. These risks are generally low, and experienced surgeons perform the procedure safely.

Frequently Asked Questions

Question: Does gynecomastia resolve on its own?

Answer: Most gynecomastia arising during adolescence resolves spontaneously. As hormonal balance settles, breast tissue generally returns to normal within 1-2 years. Similarly, newborn breast swelling disappears within a few weeks. Longstanding gynecomastia in adults, however, may not regress on its own. Even after correcting the underlying cause, fibrotic tissue may not shrink completely, and additional treatment may be required.

Question: How can gynecomastia improve without surgery? Can I do anything at home?

Answer: For pseudogynecomastia —breast enlargement due to fat— losing weight is the most effective solution. As diet and regular exercise reduce body fat, the chest also becomes slimmer. Avoiding triggers such as alcohol and steroids and changing a causative medicine under medical supervision may also help. Commercial herbal supplements and creams have no proven effect and are not recommended. For adolescent gynecomastia, patience and loose clothing to disguise the enlargement can make this temporary period easier. If there is no serious underlying hormonal disorder or excess weight, unfortunately, significant gynecomastia may not disappear completely without surgery.

Question: Can gynecomastia recur? Can the breasts enlarge again after surgery?

Answer: After gynecomastia surgery using an appropriate technique, substantial regrowth in the same area is generally not seen. Most glandular breast tissue is removed, so it is not expected to grow again. However, if the patient gains weight rapidly after surgery, increased chest fat may cause some fullness, although it may not return completely to its previous size. Postoperative anabolic steroid use or exposure to other contributing factors, such as hormonal treatments, can stimulate renewed cell growth in the small amount of remaining tissue. Otherwise, surgical correction is generally permanent and gynecomastia does not recur.

Question: Will gynecomastia surgery leave scars?

Answer: Incisions are generally very small and strategically placed. A crescent-shaped incision along the lower edge of the nipple area follows the natural color transition and leaves a barely visible scar when it heals well. Liposuction-only procedures may leave pinpoint scars of 3-4 mm, which also fade. Depending on skin characteristics, initially pink-red scars approach the skin's natural color and become difficult to notice after approximately 6-12 months. Using scar creams as advised by the doctor and protecting the area from sunlight help improve healing and appearance.

Question: Which doctor should I see for gynecomastia?

Answer: You can initially consult a general surgeon or go directly to a specialist in plastic, reconstructive, and aesthetic surgery . A general surgeon can assess the breast mass, rule out other causes, and refer you to plastic surgery if needed. A plastic surgeon specializes in surgical planning and cosmetic correction. If a hormonal disorder is suspected, an endocrinology consultation may also be requested. Booking an appointment with a hospital's general or plastic surgery clinic is a suitable first step.

Although gynecomastia is common and usually benign, it can affect quality of life. Fortunately, modern medicine can identify and treat contributing factors or achieve successful results through surgery. If you or someone close to you has symptoms, a healthcare professional can provide appropriate information and treatment when necessary. Early assessment is important both for reassurance and for choosing the most suitable approach.