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Physical Development

General Physical Changes Adolescents Experience

Although some of the physical changes that happen during adolescence are internal and not visible, others can be seen easily by others. These obvious changes in the body can affect how adults and peers of both sexes view and treat young people.

The changes that occur both inside and outside the body during adolescence happen through a process called “puberty.” This process stems from the release of certain hormones (chemicals) in the brain. These hormones released are the same in all adolescents, but differences in hormone levels lead to different results in males and females. The physical changes in adolescents shift them from their childhood bodies to their adult bodies and give them the ability to get pregnant or cause pregnancy. This ability to get pregnant or cause pregnancy is called “fertility.”

Anyone who looks at an adolescent male and female side by side will see some clear differences. Still, adolescents of both sexes exhibit many changes in common, most notably, growth spurts in height and weight. During these growth spurts, bones and muscles get longer and stronger, which allows adolescents to take on tasks they were likely not able to do as younger children, such as lifting heavy objects and walking, running, or biking long distances. Many young people will reach their full adult height by the end of puberty. Beyond the growth spurts, other physical changes that happen in both males and females include body odor, acne, and more body hair.

As noted above, many of the physical changes in adolescence are related to fertility. Some adolescents may be embarrassed by these changes at first, but they need to know that they happen to everyone. Consider this short list:

  • Females will see changes in where fat appears on their body. For example, breasts become fuller and hips grow wider.
  • Females typically experience their first menstruation (or period) during adolescence. Early on, periods can be irregular and affected by illness, stress, and even exercise. 
  • Males’ shoulders become broader and their muscles get bigger. The penis and testicles also grow, and males will begin to experience erections and ejaculations, both voluntary and involuntary (sometimes happening while asleep).
  • Males’ voices also deepen during this time and may crack during the shift. 

Beyond developing fertility, these visible sex-specific changes also let others know that a person is no longer a child. It is important to note that while the physical changes that adolescents experience happen to everyone, the timing and order of these changes will vary from person to person. 

Additional information on adolescent physical development can be found in The Teen Years Explained: A Guide to Healthy Adolescent Development, produced by the Center for Adolescent Health at the Johns Hopkins Bloomberg School of Public Health.


Content created by Office of Adolescent Health
Content last reviewed on July 29, 2018