What are puberty and adolescence?
Adolescence means the teenage years, roughly from 10 to 19. It is a time of growing in body, mind and feelings.
Puberty is the part of adolescence when the body becomes able to make a baby (it becomes sexually mature). It usually begins between 8 and 13 in girls and between 9 and 14 in boys, and takes a few years.
Starting early or late is normal. Your body follows its own clock.
Hormones: the body's chemical messages
A hormone is a chemical message carried in the blood. Hormones are made by glands.
- The pituitary gland at the base of the brain sends a message hormone.
- In girls, the ovaries answer by making oestrogen (estrogen).
- In boys, the testes answer by making testosterone.
- These sex hormones cause the body changes of puberty.
Hormones also affect feelings, which is why moods can change quickly.
Changes in the body
Changes for everyone
- A growth spurt: height and weight increase fast.
- Hair grows under the arms and around the genitals.
- Sweat glands and oil glands work harder: body smell and pimples (acne) can appear.
Changes mostly in girls
- Breasts develop; hips widen.
- Menstruation (periods) begins.
Changes mostly in boys
- The voice box (larynx) grows, so the voice breaks and becomes deeper. The bump in the throat is called the Adam's apple.
- Facial hair grows; shoulders and muscles get bigger.
- Testes start making sperm; wet dreams (night-time release of semen) are normal.
The menstrual cycle and reproductive health
About once a month, one ovary releases an egg. The lining of the uterus (womb) thickens to be ready for a baby. If no baby starts, the lining comes away as blood through the vagina: this is a period.
- Day 1–5: the period (bleeding).
- Day 6–13: the lining builds up again.
- About day 14: an egg is released (ovulation).
- Day 15–28: the lining waits; then the cycle starts again.
A cycle of 21–35 days is normal, and in the first year or two it is often irregular. Pads, tampons or menstrual cups can be used; change them regularly. Periods are healthy and nothing to be ashamed of.
Feelings, hygiene and getting help
- Feelings: you may feel shy, moody or want more privacy. Talking to a trusted adult helps.
- Hygiene: bathe daily, wash your face twice a day, wear clean cotton underwear, use deodorant if you like.
- Healthy habits: a balanced diet with iron and calcium, 8–10 hours of sleep, and exercise.
- Your body belongs to you. Nobody may touch you in a way that feels wrong. Tell a parent, teacher or doctor.
- See a doctor if puberty has not started by about 14, if periods are very painful or very heavy, or if anything worries you.
Try it: make a "puberty kit" list: what would you keep in a school bag (spare pad, deodorant, tissues, water bottle)?
Key formulas and definitions
- Adolescence: about age 10–19
- Puberty starts: girls 8–13, boys 9–14 (on average)
- Pituitary gland → ovaries (oestrogen) / testes (testosterone)
- Menstrual cycle: about 28 days (21–35 normal)
- Ovulation: around day 14 of a 28-day cycle
- Growth spurt: usually earlier in girls than in boys
Worked examples
1. Riya is 10 and taller than most boys in her class. Is something wrong?
No. Girls usually start their growth spurt about 1–2 years before boys. The boys often catch up and pass them later.
2. If a girl's period starts on 1 March and her cycle is 28 days, when will the next one start (about)?
Count 28 days on: day 1 of the next cycle is about 29 March.
3. Why does a boy's voice crack during puberty?
Testosterone makes the voice box and vocal cords grow longer and thicker. While they grow, the voice can jump between high and low before settling deeper.
Common mistakes
- Thinking puberty happens at the same age for everyone. Each person has their own timetable.
- Thinking periods are dirty or a sickness. A period is a healthy sign that the body is working.
- Mixing up adolescence and puberty: puberty is the body part of adolescence; adolescence also includes mind and feelings.
- Believing only girls have hormones changing. Boys and girls both go through big hormone changes.