To understand why we lose our hair, it is important to understand how it grows. Hair is considered dead, technically speaking. But at the root of every hair strand is a living essence of the hair. Therefore, it is alive and can die after all.
The Hair Structure
Hair grows anywhere in the body except in the soles and palms. It is divided into two major parts: the root and the shaft. The shaft is the appendage while the root lies beneath the skin surface. Basically, it is in the hair follicle where the hair grows. At the base of every hair follicle is the dermal papilla, which contains the essential nutrients for hair production.
The Hair Cycle
The hair undergoes three different stages in the hair growth cycle: anagen or growth phase, catagen or transition phase, and telogen or resting phase. The entire hair growth cycle repeats every four to five years at any one time.
In the hair matrix are rapidly proliferating cells that would generate the hair in the internal root sheath. These cells would later move up and become keratinized to form the hair.
The anagen phase is marked with the proliferation of these keratinized cells at a pace faster than any other cells in the body. Approximately 90% of the hair in the scalp is undergoing anagen phase, which lasts from three to five years. Each month, the hair grows to an average of 1.5 inch.
The catagen phase is the short transition between the anagen and the telogen phase. It lasts for about one to two weeks. In this stage, at least 1% of the hair starts dislodging from the dermal papilla, causing the follicle to shrink to 1/6 of its original length. The effect would be club hairs.
In the last stage, the telogen phase, approximately 10 percent of the hair starts shedding off. The hair stays attached to the follicle but stops growing while the dermal papilla stays in the resting phase. However, through washing, combing or the wind, the hair follicle dislodges the telogen hairs. This phase could last up to 5-6 weeks. When the telogen phase ends, the hair growth cycle begins anew.
The Bottom Line
There is a normal process by which we lose our hair. That happens during the telogen phase. In fact, we lose 50-100 hair strands a day as part of this renewal process. However, the hair growth cycle can be disrupted, causing abnormal loss of hair. These hair loss triggers include genetics, ageing, hormonal imbalance, stress, and medications among others.