Gynecomastia (Enlarged Male Breast Tissue)

Gynecomastia is an increase in the glandular breast tissue in males. It usually reflects a shift in the balance between oestrogen and testosterone activity and can affect one or both sides. It is common at certain life stages and often harmless, but because it can sometimes point to an underlying issue, a clinician may evaluate it with an examination and, in some cases, blood tests.

What gynecomastia is

Males have a small amount of breast tissue that normally stays inactive throughout life. Its growth is influenced by sex hormones: oestrogens tend to promote breast glandular tissue, while androgens such as testosterone tend to oppose it. Gynecomastia occurs when the balance shifts toward oestrogen activity, prompting the glandular tissue beneath the nipple to enlarge. This can result from more oestrogen, less testosterone, or a change in how the tissue responds to either.

True gynecomastia is different from a build-up of fatty tissue alone, sometimes called pseudogynecomastia, which can look similar but does not involve growth of the gland. True gynecomastia involves firm tissue felt as a rubbery disc directly beneath the nipple, and it may be tender, especially when it is new. It can occur on one or both sides, and the two sides are not always symmetrical. Pseudogynecomastia, by contrast, feels soft and even, without a distinct disc, and is more about overall body fat.

Common signs and symptoms

The main feature is enlargement of breast tissue, but the experience varies from person to person. Signs and symptoms may include:

• A firm or rubbery area of tissue under the nipple, on one or both sides
• Tenderness or sensitivity in the area, particularly when the change is recent
• Swelling or a visible change in breast shape
• An increase in the diameter of the dark skin around the nipple in some people
• Self-consciousness or distress about appearance, which can affect confidence and clothing choices

Features that usually prompt closer evaluation include a lump that is hard, fixed, off to one side, or accompanied by skin dimpling, nipple retraction, or discharge, since these are less typical of ordinary gynecomastia. New, painful, or rapidly growing tissue, or tissue appearing alongside other symptoms such as shrinking testicles, also warrants assessment.

What causes it

Gynecomastia often appears at natural points of hormonal change. It is common in newborns owing to the mother's hormones crossing the placenta, and it typically resolves within weeks. It is also common during puberty as hormone levels fluctuate, often easing within months to a couple of years. In older age it can return as testosterone activity tends to decline and the proportion of oestrogen relatively rises.

Beyond these natural stages, several factors can contribute. A number of medicines used for various conditions are recognised contributors, as are some recreational substances and alcohol. Conditions that lower testosterone, such as problems with the testes or pituitary, can be involved, as can conditions that raise oestrogen. Disorders of the liver, kidneys, and thyroid can play a role because they alter how hormones are produced or cleared. Rarely, hormone-producing tumours are responsible. In many people a single clear cause is not identified, and a clinician weighs the history, examination, and any tests together.

How it is diagnosed

Evaluation usually begins with a careful history and physical examination to distinguish true glandular tissue from fatty tissue and to look for features that need further attention. The history often includes a review of medicines, supplements, alcohol, and other substances, and the timing of the change. Depending on the findings, a clinician may order tests such as:

• Testosterone — to assess male hormone levels.
• Oestradiol — the main oestrogen, sometimes measured to assess the balance with testosterone.
• LH and FSH — pituitary hormones that help locate where a hormone problem lies, in the testes or higher up.
• Thyroid, liver, and kidney tests — since these systems can influence breast tissue.
• Imaging — in selected cases, breast or other imaging is used to clarify the picture and to characterise a lump that is atypical.

The table below sketches, in general terms, how the two common situations differ on examination. It is illustrative and is not a substitute for an in-person assessment.

For background on the markers themselves, see our blood tests and hormones sections, our symptoms overview, and the conditions index for related topics.

How it is generally managed

Management depends on the cause, how long the changes have been present, and how much they bother the person, and it is decided with a clinician. Gynecomastia that appears during puberty often settles on its own with time and reassurance, so a period of monitoring is a common first step. When a medicine or substance is involved, a clinician may review whether changes to it are possible and appropriate. When an underlying condition is found, treating that condition is central, and the breast tissue may improve as the hormone balance is restored.

Tissue that has been present for a long time tends to become more fibrous and less likely to reverse on its own. In such cases, or where the changes are distressing, options including surgery may be discussed. General treatment principles are outlined in our treatments section. This page is educational and is not a substitute for personalised medical advice.

Complications and when to seek care

Gynecomastia itself is usually a benign change, and its main impact is often on comfort and confidence rather than physical health. It is reasonable to seek a clinician's assessment when breast tissue is new and unexplained in adulthood, when a lump is hard, fixed, or one-sided, or when there is skin change, nipple retraction, or discharge. Prompt evaluation is also sensible when breast changes appear alongside other symptoms such as low energy, reduced sex drive, or testicular changes, so that any underlying cause can be identified.

Living with gynecomastia

For many people, particularly adolescents, gynecomastia is a temporary phase that resolves with time, and understanding this can ease worry. When it persists, the psychological impact is real and valid, and it is appropriate to raise concerns about appearance and self-consciousness with a clinician rather than dismissing them. Open discussion helps match expectations to what monitoring or treatment can realistically achieve.