What does gynaecomastia look and feel like?
The tell-tale sign is a disc of firm, slightly rubbery tissue directly behind the nipple and the dark skin around it (the areola). It can be the size of a coin or spread out to the size of a palm. The nipple may look puffy or pushed forward, and it often shows through a fitted T-shirt. In the first months the disc is often sore to touch or when a top rubs against it.
It can be on one side or both. When both sides grow they often grow unevenly, so one looks bigger than the other. The spelling changes with the country: gynaecomastia in Ireland and the UK, gynecomastia in the US. It is the same condition.
Why do men have breast tissue at all?
Everyone is born with a small amount of breast gland behind the nipple. Its growth is driven by oestrogen and held back by testosterone. Men make some oestrogen too, mostly by converting testosterone in fat tissue. When the balance tips towards oestrogen, for weeks, months or years, the gland grows.
That is why gynaecomastia turns up when hormones are moving: in newborn babies, in puberty, and again in older age. It's also why medicines, anabolic steroids, extra body fat and some illnesses can bring it on. Our causes guide goes through them one by one.
How common is it?
Very. About half of all teenage boys get some breast tissue during puberty. Up to nine in ten newborn boys have a little, from their mother's hormones. In studies of men aged 50 to 80, up to about two in three have some degree of it. Most never see a doctor about it, and most cases are mild.
Is it gynaecomastia or chest fat?
The two are often mixed up, and many men have some of each. The difference matters, because they're treated differently.
| Gynaecomastia | Chest fat (pseudogynaecomastia) | |
|---|---|---|
| What it is | Breast gland tissue that has grown | Fat on the chest, like fat anywhere else |
| How it feels | A firm, rubbery disc right under the nipple, which you can pinch and move | Soft all over, with no firm centre |
| Where it sits | Centred behind the nipple and areola | Spread across the chest and often the sides |
| Tender? | Often, especially in the first months | Rarely |
| Does losing weight fix it? | The fat around it shrinks, the disc stays | Usually, a lot |
| What treats it | Time, treating the cause, sometimes surgery | Weight loss and fitness, sometimes liposuction |
Our self-check guide walks you through the pinch test in front of a mirror.
The grades surgeons use
Surgeons grade gynaecomastia by size and by whether there is loose skin. Grade I is a small disc around the areola. Grade II spreads wider across the chest, with no extra skin (IIa) or with some (IIb). Grade III is larger, with loose skin that hangs, like a female breast. The grade matters mostly if you ever consider surgery, because extra skin changes the operation.
Is gynaecomastia dangerous?
No. Gynaecomastia itself is benign: it is not cancer and doesn't turn into cancer. Two things still need a GP. The first is the cause: now and then, new breast tissue in an adult is the first sign of something else, such as a medicine, a thyroid problem, liver or kidney trouble, or a hormone problem. The second is the rare lump that isn't gynaecomastia at all.
Don't wait on these
See your GP within a week or two, and sooner if it is changing fast, if you notice:
- a hard lump, or a lump that is off to one side rather than centred under the nipple
- a lump that is fixed and doesn't move under the skin
- fluid or blood coming from the nipple
- a nipple that has turned inwards, or skin that is dimpled, red or sore
- a swelling or lump in your armpit
- a change on one side only that is getting bigger
Most of the time these turn out to be harmless. They still need a doctor to feel them, because about 30 men are diagnosed with breast cancer in Ireland each year.
Questions people ask
Can gynaecomastia be on one side only?
Yes. It often starts on one side and sometimes stays that way. A one-sided change in an adult should still be checked by a GP, so the doctor can feel it and rule out other causes. Our one-sided guide explains what they look for.
Is gynaecomastia hereditary?
It can run in families, and some rare inherited conditions cause it. Most men with gynaecomastia have no family history at all.
Does gynaecomastia hurt?
It often does in the first months, when the tissue is growing. The soreness usually eases as the tissue settles, even if the swelling stays.
Is gynecomastia the same thing?
Yes. Gynecomastia is the American spelling of gynaecomastia. Same condition, same treatment.