Puberty for Boys: Every Change, Explained

Puberty for boys usually begins between ages 9 and 14 and continues for several years, often into the late teens. It brings changes to your height, voice, muscles, skin and more. Here is a straightforward rundown of what happens, why, and how to handle it with confidence.

Key takeaways

• Most boys start puberty between 9 and 14, and the first sign is usually testicle growth.
• Boys typically have their biggest growth spurt later in puberty, often around 13 to 14.
• Voice changes, body hair and muscle growth come gradually, not overnight.
• Chest tenderness, acne and wet dreams are common and normal.
• Puberty in boys can continue until around 17 or 18, so late changes are expected.

What starts puberty

Puberty begins when the brain signals the testicles to make more testosterone. Testosterone causes most of the changes below. Hormones from the adrenal glands also contribute to oily skin, sweat and body odor.

Testicle and penis growth

The first sign of puberty is usually that the testicles get bigger. The skin of the scrotum (the pouch that holds the testicles) may become thinner, looser and slightly darker.

About a year later, the penis begins to grow in length and then width. This happens gradually over several years.

A few things worth knowing:

• It is common for one testicle to hang lower than the other.
• Size varies widely between people and has nothing to do with health or masculinity.
• Wearing an athletic cup during contact sports protects this area.

Growth spurt and body shape

Boys usually hit their fastest growth in the middle-to-late part of puberty, often between ages 12 and 15.

During this time:

• You may grow 7 to 10 centimeters or more in a year.
• Hands and feet often grow first, which can make you feel clumsy for a while.
• Shoulders broaden and muscles get larger and stronger.
• Appetite usually goes up a lot, because your body needs extra fuel to grow.

Muscle growth continues into the late teens. Lifting heavy weights is not needed to "trigger" it, though supervised strength training with good technique is safe for teens.

Voice changes

As testosterone rises, the larynx (voice box) grows and the vocal cords get longer and thicker. This makes your voice deeper.

• The change often begins around ages 12 to 14.
• For a few months, your voice may crack or jump between high and low.
• Some boys notice their Adam's apple becoming more visible.

This phase is temporary. Once the voice box finishes growing, your voice settles.

Body and facial hair

Hair growth usually follows this order:

1. Pubic hair appears, starting fine and becoming darker and coarser.
2. Underarm hair comes about a year or two later.
3. Facial hair starts on the upper lip, then the chin and sides of the face.
4. Chest and body hair may come later, sometimes into the twenties.

How much hair you grow depends mostly on genetics. Shaving is optional and can start whenever you want.

Chest changes

Many boys notice a small, tender lump under one or both nipples. This is called gynecomastia, and it affects a large share of boys during puberty. It is caused by normal, temporary shifts in hormone levels and usually disappears on its own within months to about two years.

Erections and wet dreams

During puberty, the penis can become stiff (an erection) at random times, even without any reason. This is caused by changing hormones and is completely normal. It usually passes on its own within a few minutes.

Many boys also have wet dreams (nocturnal emissions), when a small amount of fluid called semen is released during sleep. This is involuntary and normal, and it's simply a sign the body is maturing. Rinsing off and changing into clean clothes or bedding is all that's needed.

Skin, sweat and hygiene

If acne is painful, leaves marks or affects your confidence, a doctor can help with treatment.

Fueling a growing body

Your body is doing a lot of building during puberty, so what you eat matters. Aim for regular meals with protein (eggs, fish, chicken, beans, tofu), whole grains, and plenty of fruit and vegetables. Calcium and vitamin D from milk, yogurt or fortified alternatives help bones grow strong. Drink water through the day, especially around sports, and go easy on energy drinks, which are not recommended for teens.

Feelings and emotions

Testosterone and a developing brain can make emotions feel stronger. You may feel irritable, restless or more self-conscious, and you might want more independence and privacy.

All of this is normal. Getting 8 to 10 hours of sleep, staying active and having someone to talk to help a lot. Feeling sad or anxious is nothing to hide, and reaching out is a strong move.

When to talk to a doctor

See a doctor if:

• Signs of puberty appear before age 9.
• There are no signs of testicle growth by age 14.
• Puberty starts but seems to stall for a long time.
• You have sudden or severe pain in a testicle, or the scrotum is swollen. This needs medical attention right away.
• You feel a new hard lump on a testicle.
• Chest swelling is large, painful, or lasts longer than about two years.
• Low mood, worry or stress lasts for weeks.

The bottom line

Puberty for boys is a gradual process that reshapes your body, voice and emotions over several years. Some changes may feel awkward at first, but they are all normal and they all settle down. Take care of your body, be patient with the timing and ask questions whenever you need to.