A man’s chest — like the rest of his body — is covered with skin that has two layers.

  • The epidermis is the outermost layer that provides a protective, waterproof seal over the body.
  • The dermis is the under layer that contains sweat glands, hair follicles, blood vessels, and more.

Unlike a woman’s chest, a male chest typically develops some type of thick hair growth in late puberty that usually doesn’t reach full growth until the early 30s. Like a woman’s breasts, men’s chest hair is a secondary sex characteristic, or a feature that distinguishes the differences between the two sexes. Chest hair growth depends on genetics, age, ethnicity, and hormonal status.

Like its female counterpart, the male breast has a nipple and an areola (the darker pigmented circle around the nipple), but men lack the mammary glands and ducts necessary to produce milk. A typical male does not have extensive fat deposits on his chest; in a woman, these protect the mammary glands. Instead, the shape of a man’s chest is determined by the size of the muscles underneath. 

Although atypical, men can occasionally develop large mammary glands that result in breast enlargement. This condition is known as gynecomastia. It is more common is adolescent boys but typically disappears after puberty. The cause of gynecomastia is unknown in some people, but it may be caused by steroid abuse, drug interaction, obesity, and hormone imbalance. Treatment of gynecomastia depends on the underlying cause.

Underneath the skin, all humans have a rib cage, which protects organs underneath, including the heart, lungs, liver, and more.