Understanding Hair Cycle Phases

Hair follicles repeatedly go through hair growth stages or hair growth cycles growing a little under a half inch per month and this last between 2 – 6 years. At least 90% of your hair is actually growing all the time while the others are resting.

Understanding the Hair Cycle Phases

It’s perfectly normal to shed about 100 hairs a day because the rest phase is ending and the old hair start to make room for new hair to grow.

There are three main hair growth cycles know as:

  • ANAGEN – Growing Phase
  • CATAGEN- Transition Phase
  • TELOGEN- Resting Phase
The Hair Growth Cycle

The Hair Growth Cycle

ANAGEN – This stage is the Growing Phase. The bottom of the hair follicle (the bulb) is attached to the dermis and its blood is supplied through the dermal papilla. The precursor cells, called keratinocytes, and associated melanocytes multiply at the bottom of the bulb.

The growing keratinocytes become part of the hair shaft. The upward pressure of the multiplying keratinocytes pushes the shaft up out of the follicle, where it appears as a hair.

Hair grows outward from the bulb at about 1 cm per month. The Anagen hair growth phase lasts at least 2 years on average but can vary from a few months to as much as six years. The length of time the hair follicle remains in Anagen, and keeps growing, depends on the signals it receives from the surrounding scalp and its blood supply. The cells that make up the hair follicle also communicate via the fibers in the extra cellular Matrix that provides the structure of the skin in the scalp. The hair follicle then enters the next phase of the hair growth cycle.

CATAGEN – This stage is the Transitional Phase. This phase will last between one or two weeks. When matrix cells in the hair follicle are exhausted hair growth stops. The hair follicle begins to die and enters the CATAGEN phase. This process of programmed cell death or apoptosis, results in the lower two-thirds of the hair follicle degenerating. The cells remaining form a pocket surrounding the old hair. This process occurs in a matter of a few weeks. The “bulb” of the hair follicle is drawn toward the skin surface via fibers in the extra cellular matrix, and essentially separates from the dermal papilla stopping hair growth.

TELOGEN – This stage is the Resting Phase. The remains of the hair bulb are inactive and the attached hair easily falls out. The telogen phase can last for 2 to 3 months. In the meantime, the dermal papilla remains attached to the remains of the bulb through the interconnecting network of the extra cellular Matrix. The fibers in this matrix maintain both a structural linkage and a chemical communication between the two components of the hair follicle. Without the required nutrients the follicle is slow coming back to life and can die.

LATE TELOGEN – In the final phase of Telogen, lasting a few weeks, a chemical signal causes the “bulge” and dermal papilla to re-assemble within the scalp Matrix and form a new hair follicle around the empty follicle. Stem cells within their reservoir in the bulge begin to form new keratinocytes and the cycle starts over with a new Anagen hair growth phase.

It is during the “re-awakening” process that stem cells can die and the hair follicles lose the capacity to form a new hair shaft. Preventing the loss of keratinocyte stem cells is extremely important to altering the course of hair loss and baldness. Only certain hair loss products have correct formula of natural ingrediance that can alter the course of hair loss. Products like Provillus orProcerin have these types of Key ingrediance, which is why there is such a high success rate.

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