Puberty describes the changes your body goes through as you become an adult. It includes growth spurts, periods and your voice breaking.

Puberty starts at different ages

Puberty happens to everyone but not always when they're the same age. Some people start changing when they're 10 years old. Other people don't see any changes until they're 16. Changes can happen slowly and gradually or over a short time. Girls start puberty before boys.

How puberty affects boys

Body changes

As well as getting taller, boys usually put on a little weight and their muscles begin to develop and get bigger. Your testicles and penis will also start to grow and you'll start to produce sperm.

Facial and body hair

When you're going through puberty, hair will start to grow under your armpits, on your legs and around your genitals. You'll also start to develop facial hair and you may want to start shaving. Some people also start to grow hair on their chest.

Voice breaking

Boys will also find that their voice will start to get deeper. You'll also find your Adam's apple in your throat will start to become more noticeable. When this happens, your voice has broken.

Sometimes your voice will break overnight, but usually it happens over time. Your voice may sound croaky and it will go up and down in tone. 

How puberty affects girls


Girls will start menstruating, or having their period, from around the age of 12. Menstruation begins when a girl's body has developed enough to have a baby. Once an egg is released from the ovaries, the womb grows a lining of tissue to protect it if it's fertilised by a sperm.

If the egg isn't fertilised, the egg and the womb lining will leave a girl's body through the vagina, which will cause bleeding that lasts for about three to eight days. This process is called the menstrual cycle and it happens on a monthly basis.

Periods can sometimes cause stomach pains. If the pain is always severe, make an appointment with your GP.

Body changes

Girls also grow taller during puberty and their breasts will develop.


Girls will also develop hair under their arms and around their vagina. They can also get fine hairs on their arms, legs and upper lip.

Other changes

With all the hormones going around your body, people of both sexes can develop other conditions while they're going through puberty.

These include:

  • oily skin, which can lead to outbreaks of spots or acne
  • weight increase
  • an increase in the amount of sweat your body produces
  • changes in your sleeping pattern
  • confusing feelings towards people of the same sex

Your brain releases hormones to start puberty.  Puberty can also affect your emotions and feelings. Your mood can go up and down, and you may start worrying about your body and the way you look.

Talking about puberty

Puberty can be a confusing time and you may feel pressure if you're not developing as quickly as everyone else in your class. You may want to talk to an older brother, sister or cousin if you have any worries about changes you may be going through.

You may also want to talk to your doctor or go to a nearby clinic if you have any particular health worries.

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