Five million is the approximate number of hair on the adult human body of which about 80,000 to 150,000 are on the scalp!
Hair is composed almost entirely of a protein called keratin (which is why it is important to take enough protein in your diet) and gets the black color from a pigment – eumelanin. Not everybody has hair that is black; the yellowish or reddish color of some people’s hair comes from the pigment pheomelanin.
A tubular cavity in outermost layer of skin from which the hair shaft grows is called ‘hair follicle’. All hair follicles are formed while the baby is in the mother’s womb; no new follicle is produced after birth. Each follicle is capable of producing 20-30 hair strands in a lifetime, with each hair having a life cycle of 3-5 years.
Natural growth of hair:
Hair grows at the rate of about half an inch per month. It grows fastest in summers and slowest in winters, and grows best between the ages of 15 to 30. The total length to which hair can grow is genetically determined and therefore everyone cannot grow hair to the same length.
There are three main phases of the hair growth cycle: anagen, catagen and telogen.
- Anagen is the active growth phase when hair fiber is produced.
- Catagen is the next phase - a period of status quo wherein there is neither growth nor regression of the hair strand
- Telogen is the final phase wherein the hair strand falls off and the follicle does not produce any new hair.
Every strand of hair goes through this cycle of growth, stagnation and fall. At any given point of time, about 90% of the hair strands are in the growing phase. When the ratio of hair in the growing phase and shedding phase is disturbed, the loss of hair becomes noticeable.