Catagen is the second phase of human hair growth which is the transitional phase when hair growth slows before stopping completely this is the shortest phase lasting just 10 20 days

Catagen: The Transitional Phase of Human Hair Growth

When it comes to understanding human hair growth, there are several phases that hair follicles go through. One of these phases is known as catagen, which is considered to be the second phase in the hair growth cycle. During catagen, hair growth slows down before eventually coming to a complete stop. It is a transitional phase that sets the stage for the next phase in the cycle.

Catagen is also the shortest phase in the hair growth cycle, lasting only about 10 to 20 days. In this relatively brief period, numerous changes take place within the hair follicles that eventually lead to hair shedding. Understanding the importance of catagen can help shed light on the overall hair growth process and why it is crucial for maintaining healthy, vibrant hair.

During the catagen phase, the hair follicles shrink and detach from the underlying dermal papilla, which is responsible for supplying nutrients and oxygen to the growing hair bulb. The lower part of the hair follicle, known as the dermal root sheath, undergoes a series of structural changes while the hair shaft, which is the visible part of the hair, ceases to grow any further.

As the catagen phase progresses, the hair follicles undergo involution, meaning they fold in on themselves. This folding process leads to the formation of a club hair, which is the detached hair that remains within the hair follicle. The club hair is essentially a remnant of the previous growth phase and serves as a protective barrier to the developing hair bulb.

The catagen phase is a necessary step in the hair growth cycle as it paves the way for the next phase called telogen, during which the club hair is shed and replaced by new hair growth. Without the transitional phase of catagen, the hair growth cycle would not progress smoothly, resulting in compromised hair health.

It is important to note that the duration of the catagen phase can vary from person to person, as well as throughout different areas of the scalp. Factors such as genetics, age, health conditions, and environmental influences can all impact the duration of catagen. However, on average, it typically lasts for the aforementioned 10 to 20 days.

In conclusion, catagen is the transitional phase of human hair growth when hair growth slows down before coming to a complete halt. This phase is relatively short, lasting only about 10 to 20 days, but it plays a crucial role in the overall hair growth cycle. Understanding the intricacies of catagen can help individuals comprehend the natural process of hair growth and appreciate the importance of maintaining healthy hair.

Source: Library of Congress - Why Does Hair Turn Gray?