Injerto Capilar Dr. Rafael de Freitas experto en Trasplante Capilar
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Hair grows in little groups called follicular units.
We have approximately 90 000-150 000 hairs on scalp which changes from person to person
Blond hair: 150.000
Brown hair: 115.000
Black hair: 100.000-109.000
Red hair: 90.000

Humans have from 120 to 260 hairs per cm2 approximately (60-120 follicles per cm2). There are around 90 000-15 000 hairs in the whole head.


Are 2400 follicular units the same as 2400 hairs?

For us, 2 400 follicular units correspond to 4 800 to 6 000 hairs approximately, depending on 3 or 4-hair follicular units donor site has.
In the case of 4 800 hairs it would be a patient having low follicular density. However, 6 000 hairs would be a good follicular density.

Example:  One patient having 60 follicles/cm2 corresponds approximately to 120-140 hairs/cm2.

That is why when we walk in the streets we see people who have a lot of hair volume (higher density) and other ones who have less volume (smaller density).

One follicular unit consists of:

  • 1, 2, 3 or 4 hairs in the same unit
  • 1 arrector pili muscle  
  • Approximately 9 sebaceous glands
  • Peri follicle (a colagen circumferential that defines the unit).





Depending on race there can be several variations:

  • Europeans: 2, 3-hair follicular units
  • Asiatic: 1-hair follicular units
  • Black: 2 –hair follicular units


Straight hair Follicular Units Curly hair Follicular Units



Hair does not grow in a definite way; it has a cyclic growth which is called hair growth. Each follicle has its own cycle, no matter hair surroundings.

  • Anagen Phase or Anagen: in this phase hair is stick to papilla; it is born and grows. It lasts between 4-6 years, although common average is around 3 years. Follicle shape is similar to onion shape, its base is wider than stem. Hair doesn´t stop growing because cells of the follicle are divided by mitosis continuously.
  • Catagena Phase or Catagen: It is a transition phase. It lasts around 3 weeks in which growth stops and papilla is separated. So cells´ activity stops, including melanocytes. Bulb has a cylindrical look.
  • Telogen phase or Telogen:  rest and hair loss, it lasts around 3 months. Hair root looks like a match and keeps inserted in the follicle.


Growth depending on type of hair Duration of  Anagen phase
Hair 3-5 years (1095-1825 days)
Beard 1 year (365 days)
Body hair 13-15 weeks  (91-105 days)
Eyebrow 1 month (30 days)
Moustache 4-14 weeks (28-98 days)


Every 2 days and 9 ½ hours, hair grows at least 1 more millimeter.


In men, hair grows 1cm per month approximately.


In women, it grows 1-1,5 cm per month approximately.




In animal kingdom, otter is the one which has the highest amount of hair per cm2, 100 000 hairs/cm2.


Hairs have basic functions such as adorning faces; it is the best calling card of each person.


Through different hair styles, our hair let us change our look.


An inadequate haircut can be a tragedy (nowadays in some countries there are some laws for clients who report it to the police, because of hairdresser´s negligence and professional incapacity).


However, if we have the right haircut it is possible that the person himself is able to reaffirm his roots, sex, religion; and able to challenge anything, make friends, provoke scandal, deny to social conventions or be fired of his job.


 Through the history of civilizations, hair has represented a fundamental element of human personality, beauty, fascination, seduction, and sometimes power and strength. Nowadays the same hair can preserve a deep symbolic value.


Call now and ask for your medical appointment.
+34 608 099 617

Our Centers

You can find us Monday through Friday
from 10:00 - 14:00 and 16:00 - 20:00 hours at the following addresses:

Barcelona: Plaça de Calalunya nº 1
Edif. Triangle, 4º B (Regus).
Tel: +34 608 099 617 / +34 963 355 939
Valencia: Calle de Sorní, 34
Tel: +34 608 099 617 / +34 963 355 939
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