Hair Cycle and Hair loss

If you notice your scalp carefully, you will find that some hair are long, thick and strong while others are short, thin and weak. Why so??  Here is the answer.

In human scalp growing hairs are in a constant cycle.

There is an active growing phase, called anagen phase, a stable phase with steadily diminishing hair strength called catagen and a degenerative phase in which hair falls out, called telogen phase. This is followed by a dormant period at the end of which new hair come out and anagen phase restarts.

I hope, I have not confused you further. So here is a pictorial representation of this cycle,

An anagen hair is a growing hair. During the growth phase, the hair keeps on increasing in length and becomes thick and strong. It is dark in colour and will give more volume to the mane. The anagen phase lasts for 3-4 years but may be as long as 10 years in some lucky individuals.

On the other hand, in Catagen phase, the growth of hair is over but it is yet to fall out of the scalp. These hair are frayed, thinner, weaker and less pigmented. They do not give much volume to your head. At the end of this phase, the hair falls out and the hair root goes into a resting phase for 2-3 months. This is called Telogen phase.  In a healthy scalp about 80% hair are in anagen phase, while 10% each are in catagen & telogen phase.

So what does this mean for you ? Basically it means that in a balding patient there are more telogen hair and less anagen hair. If we can increase the number of anagen hair or if we can change the ratio of anagen to telogen hair, more volume of hair can be generated from the same hair roots. Anti hair-loss medicines can prolong the duration of anagen phase and improve hair length and texture.

In my next blog I will discuss the implications of hair cycle in hair transplant patients.