Gynecomastia is the enlargement of breast tissue in males, caused by a growth of actual glandular tissue rather than just fat. It affects males at every stage of life, from newborns to older adults, and is driven by a shift in the balance between estrogen and testosterone. While it can feel alarming, gynecomastia is benign and, in many cases, resolves on its own.
What Happens in the Body
The male body produces mostly testosterone but also small amounts of estrogen. When estrogen levels rise relative to testosterone, or when testosterone drops or gets blocked, breast glandular tissue can start to grow. This tissue sits directly behind the nipple and areola, and it can feel like a firm, rubbery lump. It may be tender or sore, especially in the early stages.
This is different from what’s sometimes called pseudogynecomastia, which is simply excess fat in the chest area without any glandular growth. A doctor can tell the difference during a physical exam: when the skin is pressed together from either side of the chest, true gynecomastia produces a distinct ridge of firm tissue centered behind the nipple. With pseudogynecomastia, there’s only soft fatty tissue, and no ridge is felt until the fingers meet at the nipple itself. The distinction matters because the causes and treatments are different.
Who Gets It and When
Gynecomastia tracks closely with three periods of natural hormonal change. Newborns can develop temporary breast tissue from exposure to their mother’s estrogen during pregnancy. Boys going through puberty are the largest group affected. Roughly 75% of pubertal cases resolve within two years, and 90% resolve within three years without any treatment. Older men are the third group, as testosterone naturally declines with age while body fat (which converts testosterone to estrogen) tends to increase.
Obesity deserves a special mention. Excess weight contributes to pseudogynecomastia through fat deposits in the chest, but it also raises the risk of true gynecomastia. Fat tissue contains an enzyme that converts testosterone into estrogen, so the more fat a man carries, the more that hormonal balance shifts.
Common Causes Beyond Normal Aging
Beyond natural hormonal shifts, a range of medications can trigger breast tissue growth. The drugs with the strongest evidence include spironolactone (a blood pressure and fluid medication), finasteride and dutasteride (used for hair loss and prostate enlargement), anti-androgen drugs used in prostate cancer treatment, and estrogen-containing medications. These work through different pathways: some raise estrogen directly, some lower testosterone, and some block testosterone’s effects on tissue.
Other medications with a fair amount of evidence linking them to gynecomastia include opioid painkillers, anabolic steroids, certain calcium channel blockers used for blood pressure, the antipsychotic risperidone, and omeprazole (a common acid reflux drug). If breast enlargement appears after starting a new medication, that connection is worth discussing with your prescriber.
Medical conditions that disrupt hormone levels can also be responsible. These include thyroid disorders, kidney disease, liver disease, and certain tumors that produce hormones. Klinefelter syndrome, a genetic condition where males carry an extra X chromosome, is a well-known cause.
How It’s Diagnosed and Graded
Diagnosis starts with a physical exam to confirm glandular tissue is present. Glandular tissue as small as 0.5 cm in diameter can be detected. If there’s any concern about a hard, immobile mass, further testing is done to rule out breast cancer, which is rare in men but possible.
Doctors classify severity using a grading scale:
- Grade 1: Minor breast enlargement, no excess skin
- Grade 2a: Moderate enlargement, no excess skin
- Grade 2b: Moderate enlargement with some excess skin
- Grade 3: Marked enlargement with significant excess skin
The grade helps guide treatment decisions. Blood work may also be ordered to check hormone levels and rule out underlying conditions like thyroid problems or liver disease.
The Breast Cancer Connection
Gynecomastia itself is not cancer, but it is associated with a higher risk of male breast cancer. A large pooled study from the National Cancer Institute, analyzing data from roughly 2,400 men with breast cancer and 52,000 without, found that gynecomastia was associated with a 10-fold increased risk of breast cancer in men, independent of obesity or Klinefelter syndrome.
That sounds dramatic, but context matters. Male breast cancer is extremely rare to begin with, accounting for less than 1% of all breast cancers. A tenfold increase of a very small number is still a small number. Still, any new lump in the breast that feels hard, doesn’t move, or appears only on one side warrants prompt evaluation.
When It Resolves on Its Own
For teenage boys, the odds are strongly in favor of the condition disappearing without treatment. About 90% of pubertal gynecomastia cases resolve within two to three years as hormone levels stabilize. During that time, reassurance and monitoring are the standard approach. If the cause is a medication, stopping or switching that drug often leads to improvement, though this should always be done with medical guidance.
Treatment Options
When gynecomastia persists, causes significant discomfort, or creates psychological distress, treatment options exist. Medications that block estrogen’s effects on breast tissue have shown meaningful results. In one study of pubertal gynecomastia, 86% of patients on tamoxifen and 91% on raloxifene showed some improvement, with an average reduction in breast tissue size of about 2 to 2.5 cm. Raloxifene appeared more effective for larger reductions: 86% of patients on it saw the tissue shrink by more than half, compared to 41% on tamoxifen. These medications are typically used for three to nine months.
Surgery becomes the conversation when medication hasn’t worked, when the tissue has been present long enough to become fibrous, or when the cosmetic concern is significant. The surgical approach depends on what’s causing the enlargement. If the issue is primarily excess fat, liposuction can target and remove it precisely. If dense glandular tissue is the main problem, direct excision through a small incision near the areola is needed, because liposuction can’t break down that firmer tissue. Many men have a combination of both, and surgeons frequently use both techniques together for the most complete result.
Recovery from liposuction-based procedures tends to be smoother and faster than from open excision. Regardless of method, most men wear a compression garment for several weeks afterward, and strenuous activity is limited during healing. The grade of gynecomastia plays a role in planning: Grades 2b and 3, which involve excess skin, may require skin removal in addition to tissue and fat reduction.