Gynecomastia typically looks like a small, round area of swelling directly behind the nipple. It often starts as a button-sized lump you can both see and feel, and it can affect one or both sides of the chest. The appearance ranges from a slightly puffy nipple area to noticeably enlarged breast tissue, depending on severity.
The Telltale Signs of Gynecomastia
The growth almost always begins beneath the nipple and the surrounding areola. In mild cases, the area looks puffy or slightly raised compared to the flat chest around it. You might notice a dome-like shape to the areola, or it may appear wider than it used to be. The nipple itself can project outward more than normal.
What sets gynecomastia apart from simple weight gain is the lump underneath. It feels like a firm, rubbery disc or button sitting right behind the nipple. This mass moves slightly when you press on it and is often tender. In more advanced cases, the chest takes on a rounder, more breast-like contour that’s visible through clothing.
Clinically, the condition is graded on a four-point scale:
- Grade 1: Minor breast enlargement with no excess skin. This is the “puffy nipple” look that many people search for.
- Grade 2a: Moderate enlargement, still without excess skin. The chest has a noticeably rounded shape.
- Grade 2b: Moderate enlargement with some loose or excess skin around the area.
- Grade 3: Marked enlargement with significant excess skin, resembling a female breast.
Most cases that concern younger men fall into Grade 1 or 2a, where the change is subtle but visible enough to cause self-consciousness, especially in fitted shirts or when shirtless.
Gynecomastia vs. Chest Fat
One of the biggest questions people have is whether what they’re seeing is actual breast tissue or just fat. The two look different, and they feel very different.
True gynecomastia creates a firm mound or disc of glandular tissue concentrated behind the nipple. The puffiness is localized. Pseudogynecomastia, the term for enlarged male breasts caused by body fat, looks like a general increase in chest size spread across the whole area. There’s no distinct lump, and the tissue feels soft and compressible, similar to fat on your stomach.
You can check this yourself with a simple pinch test. Stand in front of a mirror with your chest relaxed. Using your thumb and index finger, gently pinch the tissue directly beneath your nipple and areola. If it feels soft and squishes easily, it’s likely fat. If you feel a firmer, rubbery bump or a distinct button-like mass behind the nipple, that’s more consistent with glandular breast tissue. Check both sides, since gynecomastia doesn’t always appear symmetrically.
Many men have a combination of both. Excess fat can sit on top of glandular tissue, making it harder to tell without a physical exam.
Why It Develops
Gynecomastia happens when breast gland tissue grows in response to a shift in the balance between estrogen and testosterone. All men produce small amounts of estrogen. When estrogen activity rises relative to testosterone, or when testosterone drops, the glandular tissue behind the nipple can start to grow.
This hormonal shift happens naturally at several points in life. An estimated 60 to 90% of newborns have temporary breast tissue swelling from their mother’s hormones. During puberty, prevalence estimates range from 4 to 69% depending on the study, and most of these cases resolve on their own within a year or two. It’s also common in middle-aged and older men as testosterone levels gradually decline.
Medications cause an estimated 10 to 25% of all cases. The drugs most strongly linked to gynecomastia include anti-androgen medications (used for prostate conditions), certain hair loss treatments, hormone therapies, and a blood pressure medication called spironolactone. Anabolic steroids are another well-known trigger, because the body converts excess testosterone into estrogen. Opioids, some antipsychotics, and certain heartburn medications have also been associated with breast tissue growth.
When the Appearance Suggests Something Else
Gynecomastia is by far the most common cause of a breast lump in men, but some visual features should prompt a closer look. Male breast cancer is rare, but it can also present as a growth under the nipple.
Signs that look different from typical gynecomastia include skin dimpling or puckering over the lump, nipple retraction (the nipple pulling inward instead of pushing outward), crusted or scaly skin on the nipple, bloody or clear discharge, and redness or warmth across the breast. A lump that feels hard and fixed in place, rather than rubbery and movable, also warrants attention.
When a doctor examines you and the findings clearly match gynecomastia or pseudogynecomastia, imaging usually isn’t needed. The American College of Radiology recommends against routine mammography or ultrasound in those cases. If the lump feels indeterminate or has any suspicious features, ultrasound is the first step for men under 25, while mammography is typically used first for men 25 and older.
What It Looks Like at Different Stages
In its earliest stage, gynecomastia is easy to miss visually. You might only notice a slight puffiness to one or both nipples, particularly when looking in the mirror from the side. The areola may look a little swollen or raised compared to the surrounding skin. At this point, the lump underneath is small, sometimes described as pea- or marble-sized, and it’s easier to feel than to see.
As the tissue grows, the chest develops a more rounded contour. The area behind the nipple fills out and can create a visible cone or dome shape. Shirts may fit differently, and the change becomes more apparent in thinner fabrics. The areola often stretches wider as the tissue beneath it expands.
In the most pronounced cases, the breast tissue is large enough to create a fold beneath the chest, with noticeable skin laxity. This degree of enlargement is less common but is what most people picture when they think of gynecomastia. It’s worth noting that reaching this stage typically involves a combination of glandular tissue and overlying fat, and it develops over months to years rather than appearing suddenly.