Physical changes during puberty

Whether voice change, periods or spots – the adolescent body changes in unmistakeable ways during puberty. What are the typical symptoms of puberty? And when should you consult a doctor to seek clarification about physical changes?

19.12.2023 Nina Merli 6 minutes


Teenagers experience significant growth spurts during puberty. This is the phase in which primary and secondary sexual characteristics develop. Puberty generally starts earlier in girls than it does in boys.

Growth in boys during puberty

Increasing body size is a significant feature of puberty. For example, during this phase, boys can grow by anywhere from five to eight centimetres in just a year – that's 20 to 24 centimetres by the end of puberty. This has an impact on the body’s proportions: legs become longer in relation to the torso, and muscle and fatty tissue increase. These changes can lead to growing pains in different parts of the body, such as the arms, legs or back. But it's not just bones and tissue that change. Facial and body hair increase too.

Growth in girls during puberty

Girls grow during puberty too. In particular, their legs get longer – something which, likewise, can lead to growing pains. As well as that, girls’ breasts grow, their hips get wider, and fatty and muscular tissue increase. Starting to menstruate and the growth of pubic hair are further indications of puberty.

Growth spurts in girls and boys can lead to an increased metabolic rate. This can increase the body temperature and cause increased sweating during puberty.

Puberty is a time of major transformation for teenagers and their parents, and not just a physical one. We have tips to help parents navigate this challenging period.

Emotional changes during puberty

Stretch marks during puberty

Rapid growth, weight gain and hormonal changes, but also genetics and gender, can be the cause of stretch marks, which often arise during puberty. Stretch marks, also referred to as striae, are small cracks in the elastic fibres of the hypodermis and can appear on the chest, back, stomach and thighs. Unfortunately, there are no reliable ways of completely preventing these skin changes, and there are no creams designed to remedy stretch marks during puberty. But the following tips might help to reduce stretch marks:

  • Ensure you drink enough water because hydrated skin is more elastic.
  • Eat a balanced diet with enough vitamins and minerals. Vitamin E and C are particularly important, as is zinc.
  • Skincare: care for skin regularly with a moisturising cream or nourishing oil. Products with hyaluronic acids, collagen or retinol can help to keep skin supple too.
  • Promote blood circulation: after showering, use a brush on your skin or a pluck massage. Likewise, regular physical activity promotes circulation and strengthens the connective tissue.
  • Special dietary supplements like collagen, silicon or Omega-3 fatty acids strengthen the connective tissue, thereby preventing stretch marks. Contact your pharmacist or non-dispensing chemist for advice.


During puberty, the body undergoes a great deal of change. The sexual organs mature for one, indicative of reproductive ability.

Breasts during puberty

Breast development in girls is just one of many visible changes. The mammary gland begins to grow, and the breast tissue stores more body fat. Breast growth may occasionally cause breast pain.

It is normal for one breast to be larger than the other during puberty. Breasts are rarely exactly the same size, not even in adulthood. During puberty, however, there can be greater differences. However, these more or less balance out before they finish growing. A doctor should be consulted where significant differences are observed.

Equally normal is gynaecomastia – a swelling of the mammary gland in boys during puberty. The trigger for this is an imbalance between female and male sex hormones. By the end of puberty, the swelling around the nipples usually disappears completely.

The vagina during puberty

Like the breasts, the vagina also changes during puberty. Externally, this can be seen in the growth of the vulva – the outer and inner labia become larger. Inside, the vagina produces secretions referred to as discharge. This serves to clean the vagina and prepare it for sexual intercourse.

Testicles during puberty

Physical change during puberty is set in motion by the brain, which emits various signals. For instance, the testicles begin to produce the male sex hormone testosterone. This promotes the development of the primary male sexual characteristics and is responsible for the production of sperm. During this process, the testicles enlarge. This growth can cause testicular pain during puberty, which is not usually a cause for concern. However, if the pain persists for a longer period of time, it is advisable to consult a doctor.

The penis during puberty

Testosterone also affects the growth of the penis. This changes in length and circumference during puberty. Erections will now also occur more frequently and may lead to ejaculation.

Sexual development during puberty

The increased production of sex hormones triggers the start of sexual development. Lived sexuality is now becoming an important issue for young people. In Switzerland, the average age for the “first time” is just under 17. That’s why it’s now important for parents to discuss the topic of contraception with their teenagers.

Physically, sexual development manifests itself as follows:

In boys

  • Testosterone production
  • Growth of penis and testicles
  • Erections and ejaculation
  • Increase in facial and body hair

In girls

  • Oestrogen production
  • The breasts begin to grow
  • The first menstrual period begins
  • The genitals become larger
  • Pubic and armpit hair grow

Voice change

The increased production of testosterone causes the larynx to grow. The vocal cords, which are located in the larynx, also change: they become longer and thicker. This allows the vocal cords to produce a lower pitch. But until then, the voice can fluctuate between high and low tones, sounding brittle and croaky. When does your voice break? Usually, the first signs of the voice breaking will appear anywhere between the ages of 12 and 16 and can last anywhere from six months to two years.

Do girls’ voices break too? No, girls’ voices do not break, but their voice does change, as their vocal folds and larynx grow during puberty too.


Orthodontic treatment is usually carried out in the phase of secondary dentition between the ages of 10 and 12 – i.e. before puberty. The jaw undergoes significant growth during this time. Braces can more easily compensate for misalignments of the jaw at this time.

When is the ideal time for braces? What costs are covered by health insurance?

Find out all you need to know about braces


Hormonal changes experienced during puberty can cause the hair to become greasy more quickly. This is primarily due to the increased production of sex hormones. Testosterone, in particular, can stimulate the sebaceous glands in boys and girls. Tried and tested home remedies for greasy hair during puberty include apple cider vinegar, black tea or chamomile tea, which can be used to rinse hair after shampooing.

Hormonal change can also lead to hair loss. Both boys and girls are affected by this. Hormone-related hair loss should be investigated by a doctor, as it could also be indicative of conditions such as polycystic ovaries in girls.

The skin during puberty

There’s no puberty without spots! But why do we get spots during puberty? Again, sex hormones are responsible for this. That's because the increase in these produces more sebum. The consequences: clogged pores, blackheads, inflammation, spots and acne.

What causes acne? Why do you get spots during puberty and why should you not squeeze them? More on this in our blog post about acne:

Acne: causes and treatment

Side effects of puberty:

Headaches, trouble sleeping and a lack of iron – these aren’t physical changes, but consequences of the changes adolescents undergo during puberty. Find out what you can do about these in the following articles: 

It is important to recognise that aggression, angry outbursts and mood swings are normal during puberty. These may not necessarily be directed towards parents but are an outlet for coming to terms with the many changes they are undergoing. Communicating openly and honestly can help during puberty. Accept that your child is developing a new need for autonomy. Ample patience, calm and affection are key to overcoming this challenge.

Helsana’s health consultation

Helsana’s health consultation service provided the editorial team with advice and input for this article. Our health advisors can provide you with answers to all of your health-related questions quickly and easily, whether you’d like advice on nutrition and exercise, on coping with a diagnosis or on a recommended course of treatment. 

Read more

Girls during puberty: a time of transformation
Mood swings and physical changes. How parents can best support their daughters during this stage of life.
December 20, 2023 4 minutes

Boys during puberty: from boys to men
Voice change, aggressive behaviour, tiredness – all symptoms of puberty in boys. How should parents handle this, what can you do?
December 20, 2023 4 minutes



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