Your body

It will start changing without permission from you
Image by Nicki Varkevisser CC BY 2.0 Cropped

boy2man changes

A predictable sequence


Not only are young people reaching sexual maturity earlier, but they are growing faster and taller and reaching full adult height earlier. The average boy at maturity is expected to be 3cm (1.2 inches) taller, 4.5 kg (10lb) heavier than his father and reach puberty about nine months earlier.

What to expect

All teenage boys will go through a predictable series of body changes in the transition from a boy to a fully matured man. The changes will happen in the body's own time and own speed - ready or not!

Probably a bigger surprise is the mental changes that accompany puberty. You have never felt sexually attracted towards others like you will when puberty gets a hold of your life. Other pages on this site cover that aspect of puberty.


The part of your body that a guy pees from.
The fluid that comes out your penis during ejaculation. Sperm live in this fluid (slang - cum, jizz, spooge, load, wad...)
In old Latin language it meant 'a little something shot out' and refers to semen coming out of the erect penis. (slang - cum, shoot your wad, spooge, blow your load, blast, jizz, shoot, skeet, splooge, wad, fap...)
Intense feelings and muscle contractions associated with ejaculation. The high point of feelings during masturbation or sex.
Pubic Hair
Dark curly hair that grows on your body near your penis and testicles.
Other names: come of age, adolescence, pubing, balls drop, puberbating, hormone bomb... and lots more.

Puberty concerns

  • Other boys are developing quicker than me
  • Is everything happening to me 'normal' ?
  • Can I speed up the process?
  • Why is my adult body hair so slow to grow?

Typical sequence

Age Characteristic
10 Male hormones are becoming active, but there are hardly, if any, outside signs of development. Testicles are maturing, and some boys start a period of rapid growth late in this stage.
11.5 Enlargement of the genitals, particular the scrotum, with reddening of the skin and change in skin texture. Penis hasn't grown much yet.
12.6 Appearance of breast lumps in about 30% of boys. (temporary and sometimes painful swelling of one or both breasts)
12.7 Widening of the shoulders and increase in height
Fine, soft hair appears at the base of the penis (pubic hair). Lots of erections
13.5 Dark colored curled pubic hair appears around the base of the penis. Penis gets longer but not much thicker. Penis skin becomes darker in color.
13.6 Testicles and scrotum still growing. Early voice change - deepening ('cracking of the voice').
13.7 First ejaculation of semen from the penis.
14.2 Penis width increases, as well as length. Testicles and scrotum still growing. Pubic hair begins to take adult texture, although covers a smaller area.
14.5 Period of rapid growth (growth spurt). Body/face shape look more adult.
14.9 Hair develops under the armpits. Sweat glands develop with a new odor. Pimples sometimes appear on the face.
15 Facial hair increases on chin and upper lip. Voice gets deeper and skin gets more oily. Testicles and scrotum still growing.
15.9 Maximum growth of pubic hair, spread in a tight diamond shaped pattern. Hair grows on the legs.
16 Nearing full adult height and physique. Pubic hair and genitals have adult appearance. Facial hair grows more completely and shaving may begin now or soon.
19 Mature body shape. Receding of the hair line on the sides of the forehead to form wedge pattern.
20 Some men grow a bit more and develop more body hair, especially chest hair.
22 Complete sexual maturity.
25 Brain pre-frontal cortex developed. Brain now makes rational and not just emotional decisions.

The ages given are averages and shouldn't be relied on too much. For example, the average age of a boy's first ejaculation is given as 13.7 years, but this could range from 9 years old to 18 years old as two extremes and all the other stages would adjust accordingly.

The order of events is an average also and individuals may differ in some areas. For example, you may experience ejaculation before any pubic hair has grown although the chart says the opposite. Take comfort though, that all of the events will happen in their own timing and generally in the order shown in the table. You will end up as a physically complete man.

Why the extra hair?

The extra hair on your body as an adult male serves several functions. It signals sexual maturity - that your body is capable of sexual reproduction. It also adds to the physical sensations when you have sex with another person. Finally, the hair in the groin and armpits gives off an oily substance which contributes to personal body odor. That same mechanism contributes to the bonding that occurs when two people have sex - the scent of the other person becomes imprinted in the brain alongside the pleasurable feelings of the sex act in a strong mental association that is difficult to break (Bible calls it 'the two become one flesh').


Many boys find they become easily embarrassed when others notice the physical changes taking place in their body. If someone, for example, notices and comments on the hair growing in the armpits, then a lot of boys become very self conscious and try to hide the obvious changes taking place.

You will get used to the changes fairly quickly.

Delayed Puberty

Nothing seems to attack a teenage boy's sense of well being and self esteem as much as being delayed in their physical development in relation to their friends. This is especially true if boys are required to shower together after sport (typical in the US education system). Those present, while the same age, can range from fully developed men to boys who have barely started the physical changes of puberty. It is little comfort to the late developer to know his maturity is going to happen in its own time and own pace. This boy is mostly in mental torment over his body.

What can be done?

Zinc is involved in hormone activities especially connected with (male) reproductive glands.

Make sure you eat a balanced diet that includes the foods that give you the mineral zinc. A deficiency in the mineral zinc has been linked to delayed growth and delayed sexual development in teenage boys.

Foods that have zinc: Cheese; meat; wholemeal bread; fish/shellfish; mung beans; lentils; milk; pumpkin seeds; sunflower seeds.

You could take zinc tablets obtainable from a supermarket or health food store. Recommended zinc intake - 15mg/day. Don't go above this amount or you'll cause more problems than you solve. Check with your doctor. Relax - zinc is not a drug - it is a naturally occurring mineral that appears to be lacking in western diets.

Finally, have a physical checkup with your doctor to make sure all is well with your body if you are worried about delayed puberty.

One boy's story

I acknowledge and thank the boy who allowed the world into his personal space to contribute this information and photos. He understands it may help put other young minds at ease.

Age Armpit Hair Pubic Hair (radius) Leg Adult Hair Facial Hair Voice
12/10 none first sign of hairs none none boy's voice
14 first sign of hairs 18 mm (0.7") none none slightly deeper
14/3 armpit image 23 mm (0.9") none none gradually deeper
14/6 armpit image 28 mm (1.1") none none gradually deeper
14/9 armpit image 48 mm (1.9") none none slight cracking
15 start on lower legs light colored - top lip+side of face regular cracking
15/3 personal embarrassment for our young man means the end of this series (you will probably feel the same way about this stage!)

Growing pains

'Growing pains' for teenagers refers to pain around the front of the knee. The experts can't agree on the cause of the pain. Some say it happens when the long bones of the leg grow, stretching the slower growing muscles and putting pressure on the part of the bone the muscles are attached to. Others argue that it is caused by excessive exercise in children who exercise beyond their physical ability.

Experts agree though that the pain is real and rest and muscle stretches are recommended as treatment.

Web MD website
Article on Growing Pains