Early or Late Puberty: What's Normal and When to See a Doctor

Puberty does not start on a set birthday. It can begin across a wide range of ages, and most of that variation is completely healthy. Sometimes, though, puberty starts much earlier or later than usual, and a medical check-up can help find out why and whether any treatment is needed.

Key takeaways

• Puberty usually starts between ages 8 and 13 in girls and between 9 and 14 in boys.
• Signs before age 8 in girls or 9 in boys are called precocious, or early, puberty.
• No signs by age 13 in girls or 14 in boys is called delayed puberty.
• Most late puberty is a harmless family pattern, but both early and late puberty deserve a doctor's review.
• Effective treatments are available when needed.

What is the typical timing?

Puberty begins when the brain sends signals to the ovaries or testes to start making more sex hormones. The first visible signs are usually:

• In girls: breast buds, followed by pubic hair, a growth spurt and, about two to three years later, a first period.
• In boys: enlargement of the testicles, followed by pubic hair, growth of the penis, voice changes and a growth spurt.

These numbers are guidelines that doctors use to decide when to take a closer look. Being near the edge of the range does not automatically mean something is wrong.

Early puberty (precocious puberty)

What it looks like

Signs of precocious puberty can include:

• Breast development or a first period in young girls
• Enlarging testicles or penis, or a deepening voice in young boys
• Pubic or underarm hair
• A rapid growth spurt
• Adult-type body odour or acne

Why it matters

Children who start puberty very early often grow quickly at first, but their bones also mature faster. This can cause growth to stop sooner, so they may end up shorter as adults than expected. Early physical changes can also feel confusing or isolating for a child who looks older than their friends.

Common causes

• Central precocious puberty: the brain starts the puberty process early. In girls, most cases have no specific cause found. In boys, an underlying cause is found more often, so testing is especially important.
• Peripheral precocious puberty: hormones come from a source other than the brain's usual signal, such as the adrenal glands, ovaries or testes, or from exposure to hormone creams or medicines.
• Other conditions: some genetic conditions, brain injuries or an underactive thyroid can be linked to early puberty.

Partial early changes

Some children show just one sign, such as early breast buds without other changes, or early body odour and pubic hair. These "partial" patterns are often harmless but should still be checked so a doctor can monitor them.

Late puberty (delayed puberty)

What it looks like

Delayed puberty means the first signs have not appeared by the expected age, or that puberty started but stalled. A teen may be noticeably shorter than classmates and look younger.

Common causes

• Constitutional delay of growth and puberty: the most common cause, especially in boys. These "late bloomers" often have a parent or relative who also developed late. They eventually go through puberty normally and usually reach a typical adult height.
• Long-term health conditions: such as celiac disease, inflammatory bowel disease, kidney disease or poorly controlled asthma or diabetes.
• Low energy availability: not eating enough, very high levels of training, or eating disorders can slow or stop puberty.
• Hormone or genetic conditions: problems with the pituitary gland, thyroid, ovaries or testes, or chromosome differences such as Turner syndrome or Klinefelter syndrome.

How doctors evaluate puberty timing

A visit usually starts with questions about health history, family history and when changes began. The doctor will also:

• Measure height and weight and plot them on a growth chart over time
• Do a gentle physical exam to assess the stage of development, with a parent or chaperone present
• Possibly order blood tests to check hormone levels
• Possibly request a hand X-ray to estimate "bone age," which shows how mature the skeleton is

If needed, a family doctor or pediatrician may refer you to a pediatric endocrinologist, a specialist in hormones and growth.

Treatment options

Treatment depends entirely on the cause.

• Watchful waiting: for many late bloomers and some mild early cases, regular check-ups are all that is needed.
• Treating an underlying condition: managing an illness, improving nutrition or adjusting training often allows puberty to progress.
• Medicines to pause early puberty: for central precocious puberty, doctors may use medicines that temporarily pause the process until a more typical age.
• Hormone therapy for delayed puberty: a short course of low-dose hormones can help start puberty when appropriate.

The emotional side

Developing on a different timeline than friends can bring teasing, embarrassment or worry. Reassure children and teens that bodies grow at different speeds, and that the timing does not define who they are. Talking to a counsellor can help if feelings become hard to manage.

When to see a doctor

Book an appointment with a pediatrician or family doctor if:

• A girl shows breast development or pubic hair before age 8
• A boy shows testicular growth, pubic hair or voice changes before age 9
• A girl has no breast development by 13, or no period by 15
• A boy has no testicular growth by 14
• Puberty started but seems to have stopped
• Growth has slowed noticeably compared with peers
• There are headaches, vision changes or other new symptoms alongside early changes

The bottom line

Puberty normally starts across a broad range of ages, and most differences in timing are healthy. When signs appear very early or very late, a doctor's check-up is a simple, reassuring step that can identify any cause and guide treatment if it is needed.