The cycling hair follicle

The cycling hair follicle is the structure that produces hair on our scalp and other parts of our body. It is a complex structure that undergoes cyclic changes throughout its life cycle. The hair follicle consists of several layers of cells, including the dermal papilla, the hair bulb, and the hair shaft.

During the anagen phase, the hair follicle actively produces hair, which grows longer and thicker. This phase can last for several years, depending on the location of the hair on the body. After the anagen phase, the follicle enters the catagen phase, during which the hair growth slows down and the hair follicle starts to shrink. This phase lasts for a few weeks.

The final phase is the telogen phase, during which the hair follicle is dormant and the hair is shed. This phase lasts for several months before the hair follicle enters the anagen phase again and the cycle repeats.

The regulation of the hair growth cycle is complex and involves various factors, including hormones, growth factors, and environmental cues. Disruptions in this cycle can lead to hair loss or other hair-related disorders.