Puberty: the Physical Changes for boys

Puberty is the word we use to describe the time when you body starts to change from the body of a child to an adult. Lots of changes happen to you during puberty- your body starts producing hormones, you get taller and your shoulders broaden out, your voice deepens, your penis thickens and lengthens and your testicles grow larger.

Boys tend to start puberty a bit later than girls. Most boys begin puberty between the ages of 10 and 15, the average age is 12. It can continue into your late teens and early 20s. Here we take a look at some of the physical changes that will happen during puberty. 

Your body

You can tell when you’ve hit puberty when you start getting taller and your shoulders broaden out. The rate you grow at is different for everyone but boys usually keep on growing throughout puberty. Often boys find that their arms, legs and feet grow before the rest of their body. For a while you might feel a bit awkward but the rest of you will catch up. With all this growing you might find that your joints are painful. This will pass once you’ve stopped growing.

At some point during puberty you’ll also find that the area around your nipples feels puffy and sensitive. Don’t worry, you’re not growing boobs. It’s a perfectly normal process and it’ll settle down in time. 

Your voice

At some point, your voice will ‘break’. This happens as your head and voice box grows and develops. You might find that your voice switches between low and high in a way that you can’t control. This might be embarrassing if it happens in public but it will pass. 

Your genitals

During puberty your penis will lengthen and thicken. There is no normal or average size of penis so try not to worry about your size. When penises are erect they are roughly the same size for all men. An adult penis is usually between 8.5cm to 10cm long when soft and 15cm to 18cm when erect. An erection is when the penis goes stiff, gets longer and wider, sticking out and up from the body. This happens when a man is sexually excited and is caused by the penis filling with blood. During puberty an erection can sometimes come from nowhere, usually when you least want it. This can be embarrassing but it happens to just about everyone. 

Boys can get erections when they’re younger but it’s only during puberty that they start to ejaculate. This is when a small amount of semen squirts out of the head of an erect penis. This can happen involuntarily during a ‘wet dream’. Most young guys will wake up at some point to find that they’ve ejaculated (come) on the bed sheets. This might be embarrassing but it’s completely normal. 

Many guys touch or stroke their penis to cause an erection and orgasm. This is masturbation. Despite what you may have heard, masturbating isn’t bad for you and you definitely don’t go blind. It can be a good way to find out more about your body and what feels good for you. 

The foreskin is a flap of skin that surrounds the head of the penis and you should be able to pull it back to expose the head. If you don’t wash underneath the foreskin then a smelly yellow substance can build up called smegma. It’s not bad for you but it smells bad so you should wash it every day. 

Your balls (testicles) will also grow larger and the scrotum (bag that your balls hang in) will feel thinner and the skin will get darker. One ball usually hangs a little lower than the other. You may develop spots, bumps or moles on your scrotum, this is normal so don’t worry about it. It is important to be aware of what is normal for you though as testicular cancer is the most common cancer in men aged 15 to 44 years old.


You’ll find that hair grows on lots of different parts of your body. You’ll start getting facial hair. Some guys get more than others but at some stage you’ll need to start shaving. You’ll get hair under your arms, on your chest and thick pubic hair around your genitals and inner thighs. 

Smells and spots

With all the changes it’s going through, your body will start to sweat more. Sweat that is left on the skin and clothes starts to smell pretty quickly so it’s a good idea to wash daily and change your clothes and underwear regularly. Wearing a deodorant also helps.

You may also find that your skin starts getting oily. Most people get spots and some go onto develop acne. If your acne is bad then discuss it with your doctor. They may be able to prescribe you cream or tablets to help with it.

More help and information

Teenage Health Freak- You can get more info about the changes your body will go through from the Teenage Health Freak Website. 

A below the belt guide to the male body- This booklet from the fpa will tell you all you need to know!