Growth Spurts, Voice Changes and Body Hair

Three of the most noticeable parts of puberty are growing taller fast, a changing voice and new hair in new places. They are driven by the same hormones, but each follows its own timeline. Here is what is happening inside your body, when to expect each change and how to make the ride a little smoother.

Key takeaways

• The puberty growth spurt is the fastest growth since infancy, often 6 to 10 centimeters per year at its peak.
• Girls usually have their growth spurt earlier in puberty than boys.
• Voices deepen because the voice box grows, with bigger changes in boys.
• Body hair appears gradually, usually starting with pubic hair and then underarm hair.
• Genes are the biggest factor in height, voice and hair, and healthy habits help your body reach its potential.

The growth spurt

What causes it

During puberty, rising levels of estrogen and testosterone, along with growth hormone, make the growth plates at the ends of your long bones work faster. Growth plates are areas of soft, developing tissue where new bone forms. Toward the end of puberty, these plates harden and close, and growth in height stops.

When it happens

Because girls start earlier, many are taller than boys their age for a year or two. Boys often catch up because they grow for longer before their spurt begins, and their peak is faster.

What it feels like

• Hands and feet grow first, then arms and legs, then the torso. This can make you feel clumsy or out of proportion for a while.
• Appetite increases, sometimes a lot. Your body needs extra energy and nutrients.
• Tiredness is common. Growing takes energy, and teens need about 8 to 10 hours of sleep.
• Growing pains, usually aches in the thighs, calves or behind the knees in the evening or at night, are common and harmless.

Supporting healthy growth

You can't change your genetic height, but you can help your body grow as it is meant to:

• Eat balanced meals with protein, fruits, vegetables and whole grains
• Get enough calcium and vitamin D for strong bones (dairy, fortified plant milks, leafy greens)
• Include iron-rich foods such as beans, lean meat and fortified cereals
• Sleep well, since much growth hormone is released during deep sleep
• Stay active most days

Voice changes

Why voices change

Your voice comes from the larynx, or voice box, in your throat. Inside are the vocal cords, which vibrate to make sound. During puberty, hormones make the larynx grow and the vocal cords get longer and thicker. Longer, thicker cords vibrate more slowly, which makes a deeper sound.

Boys

Boys' voice changes are usually more dramatic because testosterone causes more growth of the larynx.

• Changes often start around ages 12 to 14.
• The voice may crack or jump between high and low notes for a few months.
• The front of the larynx may stick out more, which is the Adam's apple.
• Most boys have a settled adult voice by about 15 to 16, although it can keep maturing slightly.

Girls

Girls' voices change too, just more subtly. The pitch may drop a little and the voice can sound fuller or richer. Cracking is less common but can still happen.

Looking after your voice

• Drink plenty of water
• Avoid a lot of shouting or straining
• If you sing, ask a teacher about adjusting your range while your voice changes

Body hair

What changes

During puberty, hormones turn some fine, light hair into thicker, darker hair. This happens in a fairly typical order:

1. Pubic hair usually comes first, starting sparse and fine and becoming coarser and curlier.
2. Underarm hair typically follows about 1 to 2 years later.
3. Arm and leg hair often becomes darker and more noticeable.
4. Facial hair in boys begins on the upper lip, then spreads to the chin and cheeks.
5. Chest and back hair may develop in some boys later in puberty or into adulthood.

Some girls also notice a few darker hairs on the upper lip, chin or around the nipples. This is common and usually normal.

Managing body hair

Removing body hair is a personal choice, not a health requirement. If you decide to remove it:

• Shaving: use a clean, sharp razor, shaving gel and gentle strokes in the direction of hair growth to reduce irritation.
• Trimming: a quick, painless option that avoids razor bumps.
• Other methods: creams, waxing and other options exist, but ask a parent or doctor first, as some can irritate young skin.

Never share razors, and replace blades regularly.

When to talk to a doctor

Speak with a doctor if:

• Growth seems to have stopped early or you are much shorter or taller than expected for your family.
• Growing pains come with swelling, redness, a limp, fever or happen during the day.
• Body hair appears before age 8 in girls or 9 in boys.
• A girl has a lot of coarse hair on her face, chest or back, especially along with irregular periods or severe acne.
• A voice stays hoarse for more than a few weeks.

The bottom line

Growth spurts, voice changes and new body hair are all signs that puberty is doing its job. They arrive gradually and on your own personal timeline. Eat well, rest up, be kind to yourself during the awkward phases, and know that your body will settle into its adult form in time.