3 Phases Of Hair Growth Cycle April 2, 2015

No matter who you are or where you come from, everyone has the same hair growth cycle. Despite all the knowledge that we have about hair, there are still many unknown facts about hair growth. Read on to know the answers to many unanswered questions regarding how to maintain a healthy and normal hair growth cycle, while protecting the hair against external and internal damage.

The hair is formed by the strong structural protein called Keratin. Each hair strand consists of three part namely the medulla, cortex and cuticle. Medulla is the innermost layer which is only present in thick large hair strands. The second layer called cortex is responsible for providing texture, color and strength to the hair. The third and the outermost layer is the cuticle which is colorless and thin and provides a protective coating to the cortex. The hair root which is enclosed in the hair follicle is present below the surface of the skin.

The base of the follicle contains the dermal papilla. First let us know what does this mean:

Dermal papilla: These are small, nipple-like extensions, which is directly embedded in the blood stream. The dermal papilla is responsible for deriving essential nutrients that are vital for healthy hair growth from the blood and further nourishing the hair. The dermal papilla also contains androgen receptors. Androgens are hormones that cause hair miniaturisation, regulate hair growth and can also cause hair thinning and hair fall.

Now let’s move on to the hair growth cycle.

The normal human cycle of hair growth consists of three phases namely Anagen, Catagen, Telogen. These are as described below:

Anagen:

This is the first stage of the cycle where the growth cells in the papilla split and divide to form new hair shafts. These shafts then rise from the follicles through the pores in the scalp and get keratinized. The hair follicles simultaneously penetrate deeper into the dermis to attain maximum nourishment that is vital for proper hair growth. Extended anagen growth rates ensure long hair growth with hair growing up to half an inch per month. Short growth period inhibits lengthening of hair.

[Read:Are Hair and Hormones related]

Catagen:

This transitional phase of the hair lasts for a short period of two to four weeks. Miniaturization or shrinking of the hair follicle to about 1/6th of its original size occurs during this phase. This will further result in insufficient supply of nutrients to the hair which causes the hair growth to stop. The hair however does not fall off completely even when the growth is restricted due to degraded follicles. Finally, the lower part of the follicle gets damaged and destroyed and the bulb gets disjoint from the blood supply while the papilla breaks away. The hair strand is forced upward and the follicle wastes away. This is a vital phase in the hair renewal process.

[Read:Prenatal Vitamins For Hair Growth]

Telogen:

Spanning over a period of two to four months, the third and final phase of the growth cycle of the hair is the telogen phase. The hair strand remains dormant or rests while still remaining attached to the follicle. 10% to 15% of the hair remains dormant since the papilla stays at rest during the period.

Telogen is the last stage of a growth cycle. Once this stage ends and the cycle completes, the hair restarts the growth process once again. As the growth cycle restarts, the old strands are pushed out and lost while new hair shafts get created. An individual loses about 50 to 100 strands of hair everyday as part of the normal hair growth cycle. New hair easily replaces this lost hair in no time.

However, losing more than the normal count of hair each day can result in chronic hair fall, alopecia and even balding. This excessive hair fall is the result of factors like unhealthy lifestyle, poor diet, stress, unhealthy hair care practices, hormonal imbalance, illnesses and medication, etc. If the hair enters the telogen phase early, excessive hair loss and visible hair thinning is marked.

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