Table of ContentsView AllTable of ContentsAgeFactorsGrowth in 20s
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Table of Contents
Age
Factors
Growth in 20s
Every child is unique, and so are their growth and maturation timelines. For people assigned male at birth, physical signs start during adolescence between the ages of 9 and 10 and 14 and 16, with the most rapid growth occurring between ages 12 and 15.
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A Note on Gender and Sex TerminologyNot all people assigned male at birth identify as boys.Sex and genderare different constructs although these terms are often used interchangeably in society.“Sex” refers to biological sex assigned at birth and is based on genitalia. Categories include male, female, and intersex. “Gender” refers to asocial construct of gender identity(i.e., boy, girl, nonbinary, among others). The spectrum is much more expansive and fluid.Societal norms are reflected in studies on puberty that use gendered language when discussing findings about binary sex characteristics. This article is about sex characteristics. Language may at times reflect gendered terminology used in studies and in search terms so readers can find the information they are seeking.
A Note on Gender and Sex Terminology
Not all people assigned male at birth identify as boys.Sex and genderare different constructs although these terms are often used interchangeably in society.“Sex” refers to biological sex assigned at birth and is based on genitalia. Categories include male, female, and intersex. “Gender” refers to asocial construct of gender identity(i.e., boy, girl, nonbinary, among others). The spectrum is much more expansive and fluid.Societal norms are reflected in studies on puberty that use gendered language when discussing findings about binary sex characteristics. This article is about sex characteristics. Language may at times reflect gendered terminology used in studies and in search terms so readers can find the information they are seeking.
Not all people assigned male at birth identify as boys.Sex and genderare different constructs although these terms are often used interchangeably in society.
“Sex” refers to biological sex assigned at birth and is based on genitalia. Categories include male, female, and intersex. “Gender” refers to asocial construct of gender identity(i.e., boy, girl, nonbinary, among others). The spectrum is much more expansive and fluid.
Societal norms are reflected in studies on puberty that use gendered language when discussing findings about binary sex characteristics. This article is about sex characteristics. Language may at times reflect gendered terminology used in studies and in search terms so readers can find the information they are seeking.
Age When Boys Stop Growing
Getting bigger and taller during puberty is expected, but when do boys stop growing? Generally speaking, boys start showing signs of puberty around 11 or 12 years old, with many finishing puberty about 16 years old.
Variation in Growth Timelines
Height
Between the ages of 12 and 16, boys can grow anywhere from 4 to 12 inches, with great variation in the rate of growth.Some boys do not reach their peak height until 18 years old. Still, others may continue to grow past their teen years.The average peak height for adult males in the United States is 5’9 or 69 inches.
Muscle Growth
Genitals
During puberty, the penis and testicles will increase in size. Testicles also begin producing sperms.Genitals can reach full size between 13 and 18 years of age, on average.
According to the American Academy of Pediatrics’ Healthy Children website, the testicles continue to grow, the scrotum grows larger and its skin darkens, thins, hangs down from the body, and becomes dotted with tiny bumps (hair follicles). It’s common for one testicle to hang lower than the other.
Penis Growth TimelineThepenisgrows steadily in length and girth from birth and into the later teen years, with the most rapid growth typically between ages 12 and 16.It’s said the penis typically stops growing four to six years after testes enlargement, which is typically around 18–21 years old.
Penis Growth Timeline
Thepenisgrows steadily in length and girth from birth and into the later teen years, with the most rapid growth typically between ages 12 and 16.It’s said the penis typically stops growing four to six years after testes enlargement, which is typically around 18–21 years old.
Other Pubescent Changes
You may also notice other changes during puberty. These include:
Factors That Affect Start and End of Puberty in Boys
Research suggests the age of average puberty onset is changing in many regions, with onset starting earlier. Endocrine-disrupting chemicals (chemicals that can interfere with hormones) are being studied for their impact on puberty timeline. One study from 2024 published in the journalEndocrine Practiceshows correlation between endocrine-disrupting chemicals and early onset puberty.
There are several known factors that can affect the start and end of puberty in boys. According to the Society for Endocrinology, all of the following factors play some role on puberty timing:
What You Can Do About Stress and Erectile Dysfunction
Male Growth in the 20s: What’s Possible
Around age 16, growth tends to slow, except for the muscles, which can continue developing.Muscle mass in males, for example, usually peaks between ages 20 and 30.The penis can also continue to grow into the early 20s. However, it is unlikely you will get much taller past ages 18–20.
What Is Normal?It is normal to grow at a different pace than your friends, classmates, and other peers. If concerns about growth, size, or development are causing feelings of distress, anxiety, or shame, consider reaching out for support from trusted family, friends, a teacher, a school counselor, or a healthcare provider. Many changes occur during puberty, and you do not have to feel alone.
What Is Normal?
It is normal to grow at a different pace than your friends, classmates, and other peers. If concerns about growth, size, or development are causing feelings of distress, anxiety, or shame, consider reaching out for support from trusted family, friends, a teacher, a school counselor, or a healthcare provider. Many changes occur during puberty, and you do not have to feel alone.
Signs of Puberty: What Happens to Your Body?
Summary
Everyone grows at their own pace. In people assigned male at birth, signs of puberty typically start around ages 11–12 and peak around age 16, with some exceptions. Growing taller is still possible until around 18–20 years old, and muscle mass development typically peaks in males during their 20s and 30s.
The timelines are general guidelines, but great variation exists both in total amount of growth and rate of growth during puberty. If you have concerns about healthy development or what’s considered normal during puberty, consider talking to someone you trust.
12 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Nemours KidsHealth.Growth and your 13- to 18-year-old.Society for Endocrinology.Timing of puberty: Why is it changing?Hyde JS, Bigler RS, Tate JD, van Anders SM.The future of sex and gender in psychology: five challenges to the gender binary.Am Psychol.2019;74(2):171-193. doi:10.1037/amp0000307American Academy of Pediatrics. Healthy Children.Physical development in boys: What to expect.Society for Endocrinology.Timing of puberty: why is it changing?Children’s Wisconsin.Puberty: Adolescent male.Centers for Disease Control and Prevention.Body measurements.Tomova, Analia.Growth and development of male external genitalia: a cross-sectional study of 6200 males aged 0 to 19 years.JAMA Pediatrics. doi:10.1001/archpediatrics.2010.223Young Men’s Health.When will my penis stop growing in size?Peralta M, Lizcano F.Endocrine disruptors and metabolic changes: Impact on puberty control.Endocrine Practice.2024;30(4):384–397. doi:10.1016/j.eprac.2024.01.006Batsis JA, Buscemi S.Sarcopenia, sarcopenic obesity and insulin resistance.IntechOpen. 2011. doi:10.5772/22008Centers for Disease Control and Prevention.2 to 20 years: Boys stature-for-age and weight-for-age percentiles.
12 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Nemours KidsHealth.Growth and your 13- to 18-year-old.Society for Endocrinology.Timing of puberty: Why is it changing?Hyde JS, Bigler RS, Tate JD, van Anders SM.The future of sex and gender in psychology: five challenges to the gender binary.Am Psychol.2019;74(2):171-193. doi:10.1037/amp0000307American Academy of Pediatrics. Healthy Children.Physical development in boys: What to expect.Society for Endocrinology.Timing of puberty: why is it changing?Children’s Wisconsin.Puberty: Adolescent male.Centers for Disease Control and Prevention.Body measurements.Tomova, Analia.Growth and development of male external genitalia: a cross-sectional study of 6200 males aged 0 to 19 years.JAMA Pediatrics. doi:10.1001/archpediatrics.2010.223Young Men’s Health.When will my penis stop growing in size?Peralta M, Lizcano F.Endocrine disruptors and metabolic changes: Impact on puberty control.Endocrine Practice.2024;30(4):384–397. doi:10.1016/j.eprac.2024.01.006Batsis JA, Buscemi S.Sarcopenia, sarcopenic obesity and insulin resistance.IntechOpen. 2011. doi:10.5772/22008Centers for Disease Control and Prevention.2 to 20 years: Boys stature-for-age and weight-for-age percentiles.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Nemours KidsHealth.Growth and your 13- to 18-year-old.Society for Endocrinology.Timing of puberty: Why is it changing?Hyde JS, Bigler RS, Tate JD, van Anders SM.The future of sex and gender in psychology: five challenges to the gender binary.Am Psychol.2019;74(2):171-193. doi:10.1037/amp0000307American Academy of Pediatrics. Healthy Children.Physical development in boys: What to expect.Society for Endocrinology.Timing of puberty: why is it changing?Children’s Wisconsin.Puberty: Adolescent male.Centers for Disease Control and Prevention.Body measurements.Tomova, Analia.Growth and development of male external genitalia: a cross-sectional study of 6200 males aged 0 to 19 years.JAMA Pediatrics. doi:10.1001/archpediatrics.2010.223Young Men’s Health.When will my penis stop growing in size?Peralta M, Lizcano F.Endocrine disruptors and metabolic changes: Impact on puberty control.Endocrine Practice.2024;30(4):384–397. doi:10.1016/j.eprac.2024.01.006Batsis JA, Buscemi S.Sarcopenia, sarcopenic obesity and insulin resistance.IntechOpen. 2011. doi:10.5772/22008Centers for Disease Control and Prevention.2 to 20 years: Boys stature-for-age and weight-for-age percentiles.
Nemours KidsHealth.Growth and your 13- to 18-year-old.
Society for Endocrinology.Timing of puberty: Why is it changing?
Hyde JS, Bigler RS, Tate JD, van Anders SM.The future of sex and gender in psychology: five challenges to the gender binary.Am Psychol.2019;74(2):171-193. doi:10.1037/amp0000307
American Academy of Pediatrics. Healthy Children.Physical development in boys: What to expect.
Society for Endocrinology.Timing of puberty: why is it changing?
Children’s Wisconsin.Puberty: Adolescent male.
Centers for Disease Control and Prevention.Body measurements.
Tomova, Analia.Growth and development of male external genitalia: a cross-sectional study of 6200 males aged 0 to 19 years.JAMA Pediatrics. doi:10.1001/archpediatrics.2010.223
Young Men’s Health.When will my penis stop growing in size?
Peralta M, Lizcano F.Endocrine disruptors and metabolic changes: Impact on puberty control.Endocrine Practice.2024;30(4):384–397. doi:10.1016/j.eprac.2024.01.006
Batsis JA, Buscemi S.Sarcopenia, sarcopenic obesity and insulin resistance.IntechOpen. 2011. doi:10.5772/22008
Centers for Disease Control and Prevention.2 to 20 years: Boys stature-for-age and weight-for-age percentiles.
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