How does the body produce and grow hair?

How does the body produce and grow hair?

Formerly hair was studied only for aesthetics, but today scientists consider hair strands as a mirror of the human body. Little scientist, do you know how hair grows and is produced? If not, discover it with us on our blog!

Hair is composed of stamen and root. The stamen emerges from the surface of the scalp while the root is implanted in the hair follicle. Both are constituted as follows:

  • The hair follicle is the hair production unit. Every day, all of our hair follicles produce one million new keratinocytes. These cells synthesise keratin, a fibrous protein that makes up the hair and makes it extremely solid. The follicle has, at its lower end, a bulb with the dermal papilla at its base. There, small blood vessels flow in charge of transporting the nutrients and oxygen necessary for hair growth. Above the bulb is the sebaceous gland, the source of sebum production. In this way, the hair is permanently lubricated.
  • The stamen is composed of three parts: marrow, cortex and cuticle.


What is the function of hair and how does it renew itself?

 The hair has the same type of structure as the skin and performs various functions: physical barrier, immune protection, thermal insulation and more. Its main function is to protect the head. Cellular renewal of the scalp occurs in 14 days, but can be accelerated in case of inflammation. Their dead cells are eliminated in the form of tiny and invisible scales, but in case of inflammation and hydro-dissection, the dead cells accumulate and become visible, forming the famous dandruff.


Curiosities about hair:

  • All of the hair follicles in humans are formed when a foetus is 5 months old.
  • Hair grows slightly faster in warm weather, because heat stimulates circulation and encourages hair growth.
  • Black is the most common hair colour. Red is the rarest and only exists in about 1 % of the world’s population, with blonde hair found in 2 %.
  • A single hair has a lifespan of about five years.
  • Around 100,000 to 150,000 is the average number of hairs on the head and it’s normal to loose it from 40 to 150 everyday.
  • Wet hair becomes very elastic when it’s wet and can stretch by up to 30% without being damaged.
  • Jonathon Rees has studied the makeup of hair for more than 20 years. His major specialty is red hair and he became the person in charge of the discovery of the gene that gives the red pigmentation to the hair, the MC1R.


We hope, we satisfied your curiosity, little scientists!  Keep tuned to our blog if you want to find out more interesting scientific fact and our latest news!



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