Have you noticed hair growing on your body where there was no hair before? Are you having trouble singing those high notes in music class that used to be easy? Maybe you’ve noticed the boys around you have started shaving, and you’re wondering when you’ll have to start. Well, you’re not alone. Everyone goes through puberty—the transition from being a teenager to being an adult.

Puberty is a time of big changes in your body, mind, and life. This health guide will answer many of your questions.

What is puberty?

During your teenage years, your body will go through several changes as you become an adult. This body development is called puberty. At the start of puberty you will notice hair growing around your penis, under your arms, and on your face, chest, and legs. Your testicles and penis are also growing. You may develop acne (pimples). Later in puberty, you will begin to grow taller and your voice will start to change and get lower.

How old will I be when I start puberty?

Take a look around any middle school or junior high. You will see that a few of the guys have already started puberty. They may shave and have hair on their face, arms, or back. They may have deep voices. Other guys have not started their growth spurt. They have little or no hair on their face, and may have a higher voice. That is because puberty starts at different times for everyone. It can start as early as 10 years old and as late as 14 or 15 years old. Most guys have some growth of their testicles by about age 12. This is the first sign that puberty has started. Once it starts, most guys complete their development in 2 to 5 years.

Girls start puberty sooner and faster than boys do. Girls usually begin to grow taller 2 years younger than boys do. But because boys have more years to grow and a bigger growth spurt, they usually end up taller than girls.

What happens during puberty?

The first body change is growth of your testicles. You may not even notice this growth, but it is the first sign that your body is starting puberty. Hormones from a special part of the brain cause the testicles to grow bigger. The skin of the scrotum (the sac that hangs beneath the penis and contains the testicles) becomes thinner and the testicles hang lower. Later, pubic hair develops around the base of the penis and scrotum. The penis also begins to get bigger.

Remember, every guy goes through puberty at his own pace. The timing of how your body grows is determined mostly by genes, which means that it is inherited from your parents. Your brain may grow and mature differently from the body (either faster or slower). Poor nutrition can also affect puberty. That’s why healthy eating is important. Other chronic medical conditions such as Crohn’s disease or sickle cell disease can also affect growth. So, if you haven’t started puberty by age 14, see your health care provider for a check-up.

The rest of your body:

Meanwhile, the rest of your body goes through its own changes. Hair begins to grow under your arms. Later, hair may grow on your face, arms, legs, and chest. Your body grows taller and more muscular. You may experience some pains in your arms and legs as your muscles stretch to keep up with your growing bones. Your voice will begin to get deeper. As this happens, you may notice your voice crack, but this problem will not last long.

You might also notice swelling and tenderness underneath your nipples. Some guys worry that they will start growing breasts or that something is wrong with them. The swelling is caused by hormones that are released during puberty. The swelling goes away with time. If the swelling doesn’t go away within a year or you are worried, you should see your health care provider.

Body odor:

You may notice that your body has started to smell different, or smell more, especially after sports or at the end of the day. This is one of the common features of puberty, and is normal. Around this time you may have to start taking a shower every day, and also using deodorant or antiperspirant.

Acne:

Acne (pimples) is common during puberty. Acne is caused by increased skin oil and a particular kind of bacteria that grows inside the pores of your skin. Acne can be controlled with good hygiene and medications. Scrubbing your face may actually make the acne worse.

Thoughts and Feelings:

Most guys have a lot of emotional ups and downs during puberty. You may find that you feel sad or angry and don’t know why. You may feel bad one moment and happy the next. You might feel worried about what other kids think about you. And you may feel like you don’t want to be as close to your parents as you used to be. These feelings are all a normal part of puberty and come and go in your early teen years. If you feel sad, angry or depressed for more than 2 weeks or have trouble doing everyday things like going to school, you should talk to an adult about how you are feeling. Some good choices are your parents, school counselor or doctor.

How can I stop feeling embarrassed about my body?

Remember that puberty is a temporary phase of life that everyone experiences. Those cracks in your voice won’t last, and eventually your body will reach a steady size and shape. If you’re worried about your growth and development or have questions about your body, talk to an adult you trust — a parent, guidance counselor, or your health care provider.