Growth of Hair
Keratin is a protein that makes up hair and also stimulates hair growth. Hair has a growth cycle with three concurrent and distinct phases. Each phase has specific characteristics that determine the length of hair.
Life cycle of Hair
Each strand of hair on our body is at different stage of development. After the cycle of Anagen, Catagen and Telogen is complete, the hair is gone and a new cycle restarts with a new strand of hair being formed.
Speed of Hair Growth
The speed of hair growth is nearly 1.25 centimeters or 0.5 inches per month. This means that hair grows about 6 inches in a year.
Factors that increase the risk of developing Spider Veins
This is the growth phase. The longer the hair stays in the anagen phase, the longer it will grow. 85% – 90% of the hairs on one’s head is in this phase at any given time.
- Hair grows approximately 1.25 cm per month.
- It begins in the papilla and can last from two to six years.
- The duration at which the hair remains in this stage of growth is decided by the genetics of the person.
- During this phase, cells surrounding the papilla divide to produce new hair fibers and the follicle buries itself into the dermal layer of the skin. The dermal layer contains nerve endings, sweat glands, and oil (sebaceous) glands, and blood vessels which nourish the strand or hair follicle.
This phase is, also known as the transitional phase. Here, the follicle renews itself.
- This phase lasts about two weeks.
- The hair follicle shrinks due to disintegration and the papilla detaches and “rests,” cutting the hair strand off from its nourishing blood supply.
- The body sends signals for the Anagen phase to end and the Catagen phase to begin.
- Hair is not growing during this phase, but the length of the terminal fibers increases when the follicle pushes them upward.
- 1 % hair on the head generally are in this phase.
This is a resting or shedding phase for hair. The follicle remains dormant for one to four months.
- 10 to 15% of the hairs on one’s head are in this phase at any point in time.
- The hair base will break free from the root and the hair will be shed.
- Within two weeks the new hair shaft will begin to emerge once the Telogen phase is complete.