It's normal for puberty to start any time between the ages of 8 and 14 years old.

Some of the signs of puberty include:

• hair starting to grow around the armpits and genitals (penis or vagina)
• boys developing a larger penis and testicles, and a deeper voice – this can happen to anyone with a penis
• girls developing breasts and starting periods – this can happen to anyone with a vagina

If signs of puberty start before the age of 8 years, this could be early puberty.

If puberty has not started by the age of 15 years, this could be delayed puberty.

See a GP if:

If a GP suspects early or delayed puberty, they may recommend some tests.

They'll usually only do this if they think a condition could be causing it.

Some of the tests for early or delayed puberty include:

• blood tests to check hormone levels
• an X-ray of the wrist, which can be used to work out how tall someone is likely to be as an adult
• an ultrasound scan or MRI scan to check for problems inside the body

Treatment for early or delayed puberty is usually only needed if it's causing physical or emotional problems.

The main treatments include:

• treating a condition that may be causing it
• medicine that can delay or start puberty

It's not always clear what causes early or delayed puberty, but it can sometimes run in families.

Some of the conditions that can cause early or delayed puberty include:

• problems with the ovaries, testicles or hormones
• certain conditions, such as cystic fibrosis or diabetes
• damage to the brain – from surgery, radiotherapy, infection or a severe head injury, for example
• not getting enough nutrients from food (malnutrition) – caused by conditions like coeliac disease or an eating disorder
• differences in sex development (DSD) – rare conditions that affect genes, hormones and reproductive organs

Further information

Read more about puberty on the Brook website.