Hair Loss - How does it happen?

All hairs will fall out because they have a life cycle.

The life cycle of hair:

Anagen Phase This is the phase of the hair follicle’s growth. 90% of the hairs on one’s scalp are in this phase.

Catagen Phase This phase lasts for only a few weeks. During this time the hair follicle stops growing and the lowest portion of the follicle becomes smaller and begins to push its way toward the scalp. In an adult, approximately 1% of the hair are in this phase.

Telogen At the end of this process hair falls out, but usually, before this happens, a new hair follicle is being born in its place. On a healthy scalp, approximately 4-25% of the hair are in this phase.

There are only two types of hair:

      1. Those that do not have the genetic code for hair loss;
      2. Those that do have the genetic code for hair loss.

The hairs that DO NOT have the genetic code for hair loss are thick when they fall out and can be found in your hair brush, drain, or on your pillow. To the extent that these hairs fall out, new hairs just like them are growing and replacing them.

Life Cycle of Normal Hair

Contrarily, the hairs that “have the genetic code for balding” are not replaced by new hair growth when they fall out. Also, unlike normal hair, they are not thick when they fall out.

The hairs that have the genetic code for balding have receptors in their roots for a hormone called dihydrotestosterone (DHT).
This hormone connects itself to these receptors causing the hairs to gradually weaken and shrink in size until they transform into very thin and short hairs. This process is called Miniaturization and the hairs involved are called miniaturized hairs, which are invisible to the naked eye. When these hairs fall out they are not replaced. (see clinical treatment for hair loss).

DHT causes the progressive miniaturization of the hair follicles,
weakening the hair.


Microscopic image of the scalp (50x)
Note the atrophy process of the hairs within the same area.