The Truth About Hair Growth

Nothing in life is as simple as it seems, so it should come as no surprise that the strand of hair you found on your brush this morning is an amazingly complex part of your body. The hair, while still in the womb, begins to appear on the human body. By the time a developing fetus becomes 22 weeks old, there are already 5 million follicles on the body. Interestingly, these are all follicles that will develop independently of how long we live. None will ever be added.

Hair Anatomy

The hair consists of a follicle embedded in the skin and the hair shaft that appears on our body. The follicle itself consists of several layers, each layer having a specific function. The papilla lies at the base of the follicle. The capillaries are connected to the optic disc and provide the cells with blood that surrounds the lower part of the strand of hair, which is called bulb.

Around the follicle are two inner and outer sheaths that protect the hair shaft from damage and help it grow in the right direction. The inner shell runs next to the hair shaft and ends at the sebaceous gland. The outer shell runs to the gland and ends at the M. erector pili. This is the muscle that causes our hair to "stop" when they contract.

The hair shaft consists of three layers of dead protein cells called keratin. The innermost layer, the so-called medulla, is not always present in every hair shaft. The second layer, known as the cortex, provides the majority of the hair shaft. The hair color is mainly determined by the pigmentation contained in this layer. The outermost layer is called cuticle. It consists of a series of overlapping cells. The shine and shine of the hair comes from the cuticle.

How the hair grows

Scalp hair grows at an average rate of six inches a year, or just 0.3 to 0.4 mm a day. There are three different stages of hair growth.

- catagen phase

This transitional phase takes about two to three weeks. At any time, about 3% of your hair is in this phase. During this time there is no hair growth, while the outer part of the hair root sheath shrinks and attaches to the root.

- Telogen phase

This phase, known as the "rest period", is experienced by about 15% of your hair. Telogen lasts about 100 days for the hair of the head and much longer for other body hairs.

- anagen phase

This phase defines a period of activity in which the hair cells divide and new hair growth occurs. This phase can take two to six years. Shorter periods of growth point to people who have problems with long hair.

Hair growth disorders

There are two hair growth disorders that affect humans. Hirsutism is a disease that mainly affects women. It is defined as a condition in which excessive thick and dark hair growth occurs in areas typically reserved for men. These areas include the face, breast, and areola, or the area surrounding the nipple. Hypertrichosis is a condition that causes excessive hair growth in areas of the body where normally no visible hair is present. Both conditions are treatable.