T at work – body hair and pubic hair: Growing in new places


As kids, our body has hair that is thin and often light in color. During puberty, some people’s hair—under the arms, around the genitals (pubic hair), and on the legs—grows darker and thicker. Some young people’s facial hair will grow darker, too.



Why does hair get longer and darker?

This change comes from hormones including testosterone (T). When T in the blood reaches the area under the skin, those hair follicles mature and make hair darker and thicker. Like with all skin, once hair follicles mature, they will stay that way.

If you don’t have much T or don’t react to it, this hair may not develop or it may only develop in a small amount.

If you have T, but can only partially react to it, you will probably experience some hair changes around your body. Each body is different, and it is difficult to say exactly what to expect.

How will it change—what can I expect and when will it happen for me?

Everybody is different. Some young people see changes start underneath their arms in the armpit. The hair can pop up in new places and feel weird at first. Some young people grow tons of body hair, and some don’t. Some of this depends on when your body is going through puberty; some people start puberty as early as age 8. Other people begin puberty in their teens.

While some young people do grow a mustache or beard, others don’t.

Sometimes, this might be because of how your hair follicles respond to T. Other times, it might just be part of your genes and family history.