Testosterone in teens: what it does in boys and girls
Testosterone is a hormone that rises in puberty and helps drive body changes like growth, muscle, voice and body hair. Boys make much more, and girls make smaller amounts too. It is only weakly linked to aggression. Sleep, daylight and steady company help teens feel their best.
Teo: builds strength, energy and confidence in the teen years
Say it to your kidTeo is the part of puberty that helps your body grow stronger and changes some things, like your voice, your height and your energy. Everyone gets changes on their own schedule, and nobody’s is a race. If you ever have questions about your body, you can ask me, and I won’t make it weird.
What does testosterone do in teens?
Testosterone is one of the hormones that rise in puberty. It helps drive growth spurts, more muscle, a deeper voice, body hair and changes in skin and body odor. Boys’ bodies make much more of it than girls’ bodies do, and girls make smaller amounts that matter too. Girls’ main puberty hormone is estrogen, and the two work alongside other hormones.
In the crew, Teo stands for strength, energy and confidence in the teen years. As ever, Teo is a picture of what a body does, not a measurement of your teen. We never guess hormone levels from behavior.
When does puberty start, and what counts as normal?
Puberty typically starts between ages 8 and 13 in girls and 9 and 14 in boys, according to the National Institute of Child Health and Human Development. The NHS gives a range of 8 to 14 and suggests a check if signs start before 8 or haven’t started by 15. A friend who starts two years earlier or later is still very much within normal.
Younger kids sometimes show an early hormone step called adrenarche, with body odor or the first hairs around ages 6 to 8. That is a different step, and it’s common.
Does testosterone make teens aggressive?
No, and this is one of the stickiest myths about teenage boys. Meta-analyses, which pool many studies, find only a weak link between testosterone and aggression: a correlation of about 0.14 across 45 studies in 2001, and closer to 0.05 in a 2020 update. For comparison, a correlation of 0 means no relationship at all.
In plain terms, a teen’s hormones do not explain a slammed door. Plenty of other things do: sleep debt, stress, hunger, friends and the very real work of becoming a person. Calling a teen “hormonal” can also close down a conversation they needed to have.
We’d rather say: puberty brings big changes, and your teen needs your steady company while they happen.
What really changes a teen’s behavior?
Three things usually explain more than hormones do. First, the body clock shifts later, so teens feel sleepy later and need more sleep than they get. In one major review, average school-night sleep dropped by about an hour and a half between sixth and twelfth grade.
Second, friends matter more. Researchers who scanned teens playing a simulated driving game found that knowing two friends were watching from the next room raised both risky choices and activity in the brain’s reward circuitry. Third, Fronti, the planning and brakes part of the brain, is still under construction. Together, these changes look like moodiness, bold choices and late nights without any hormone-based excuse.
What helps teens feel strong and steady?
In the crew picture, Teo likes the basics. We don’t claim these habits raise any hormone level, only that they support teens in general:
- Protect sleep. Agree on a phone-off time that allows a full night.
- Make room for sport or strength games. Pick what they actually enjoy.
- Get daylight. A walk, a bike ride, time outside.
- Regular meals with real food. Not a diet, just steady fuel.
- Side-by-side talks. Cars, cooking and walks beat sit-down interviews.
What you’ll see at home
- Growth spurts, a deeper voice, new body hair or acne
- Big energy swings, from restless to wiped out
- A teen who’s more self-conscious about their body or about who’s ahead or behind
- Wanting to be alone or with friends more than family
Try tonight
- Agree on a phone-off time that gives your teen a full night’s sleep, and keep your own phone to the same rule.
- Pick one sport, walk or workout this week and put it on the calendar.
- Offer one low-pressure chat on a drive or while cooking, and let them lead.
What to say
Instead of“Don’t be so hormonal.”
Say“A lot is changing right now. I’m here if you want to talk.”
It respects what they’re going through without blaming a hormone.
Instead of“Why are you so angry all the time?”
Say“You seem like you’ve got a lot on your plate. Want a snack and a walk?”
It opens a door instead of labeling.
Want the whole crew on your side?
The Kid Brain Toolkit: the 12 hardest moments decoded, from screens off to bedtime, with what to say and what to try tonight. Read it in one evening.
See the plansThe Toolkit is $9, one payment. For learning only, not medical advice.
Questions parents ask
Do girls have testosterone too?
Yes, in smaller amounts, made in the ovaries and adrenal glands. It plays a role in girls’ growth and body changes, alongside estrogen and other hormones.
Is testosterone why my teenage son is so moody?
Not by itself. Evidence for testosterone as a cause of aggression is weak. Short sleep, stress, hunger and peer pressure explain more than hormones.
Can I help my teen with food or exercise to “boost” testosterone?
We don’t talk about boosting any hormone. We do suggest habits that help any teen feel steady: sleep, movement, daylight and regular meals.
How do I talk to my child about puberty?
Think a hundred small talks, not one big one. Keep it short, casual and side by side, and follow their questions. See our page on talking about puberty.
Keep reading
- Does testosterone cause aggression in teen boys?Barely. A 2020 meta-analysis found a very weak link between testosterone and aggression. What drives teen anger is sleep, stress and a growing brain.
- How to talk to your child about puberty: what to say and whenHow to talk to your child about puberty: when to start, what to say, how to keep it short and calm, and what to do when you don’t know the answer.
- Tween brain development: what’s normal for an 11 year old?Puberty starts, friends matter more and moods get bigger. What’s normal for tweens aged 10 to 12 and how to stay close without hovering.
- 13 year old brain: what’s normal at ages 12 to 14?Why early teens grow fast, fall asleep late, chase rewards and go quiet at home, plus how much sleep they need and what helps you stay close.
- Teenage brain development: what’s normal for a 15 or 16 year old?Why teens care so much about friends, take risks and stay up late, and what helps: deals instead of orders, real wins and sleep before screens.
- Why do teenagers take more risks with friends?In a 2011 lab study, only teens took more risks when friends watched. How the reward system and Fronti’s brakes explain it, and what helps.
- How much sleep does my child need? Hours by age, 4 months to 18AASM sleep hours for kids from 4 months to 18, signs your child is short on sleep, why teens run late, and how light, screens and bedtime change things.
- Meet the crewAll 26 characters, grouped.
- GlossaryThe words in this site, in plain English.
Sources
- Book, Starzyk & Quinsey, 2001; Geniole et al., 2020. Meta-analyses of testosterone and aggression.
- NICHD. Puberty; NHS. Early or delayed puberty.
- Carskadon & Tarokh, 2014. Developmental changes in sleep biology and potential effects on adolescent behavior and caffeine use. Nutrition Reviews 72(Suppl 1).
- Chein, Albert, O'Brien, Uckert & Steinberg, 2011. Peers increase adolescent risk taking by enhancing activity in the brain's reward circuitry. Developmental Science.
Educational content only, built on everyday habits. It’s not medical advice, a diagnosis or a treatment. If something about your child’s sleep, mood, growth or behavior worries you, talk to your pediatrician.