I know many of us are often concerned about the amount of shed hair that we see, me included! And, we’ve probably all heard that shedding 50-100 hairs a day is normal. And, we know that most of the hairs we are seeing are shed and not broken, because we see and/or feel the bulb on one end of the strand.
But, despite all that, when we see those strands falling free on days that we wear our hair down (hand in hair syndrome, also known as HIH, is often an accomplice) and see that hair ball getting bigger on wash day as strands litter the bathroom floor, shower walls and drain, it can be unnerving and anxiety-inducing.
And, when I become concerned about my hair, I put on my research cap and try to understand what is happening. Hopefully, what I’ve learned will be of benefit to others! So, here is a little information about the three phases of the hair life cycle.
The 3 phases of the hair life cycle
Anagen Phase – Growth Phase
Approximately 85% of all hairs are in the growing phase at any one time. The Anagen phase or growth phase can vary from two to six years. Hair grows approximately 10cm per year and any individual hair is unlikely to grow more than one meter long.
Catagen Phase – Transitional Phase
At the end of the Anagen phase the hairs enters into a Catagen phase which lasts about one or two weeks, during the Catagen phase the hair follicle shrinks to about 1/6 of the normal length. The lower part is destroyed and the dermal papilla breaks away to rest below.
Telogen Phase – Resting Phase
The resting phase follows the catagen phase and normally lasts about 5-6 weeks. During this time the hair does not grow but stays attached to the follicle while the dermal papilla stays in a resting phase below. Approximately 10-15 percent of all hairs are in this phase at an one time.
[W]hat many people do not know is that the widely quoted scientific figure is in fact based on 2-3 small scale studies which account for as few as 2 individuals. There are in fact no studies which actually track a reasonable group of individuals over a period of years to firmly determine how long the hair growth cycle actually is.
Furthermore there is evidence that this 2-6 year widely accepted length could be considerably wrong. One interesting study which measured hair length of visitors to US theme parks and hair lengths recorded online on long hair sites, came to the conclusion that the average normal length of the anagen phase could be as long as 12 to 14 years.