Normal Hair Growth Cycles
Undisturbed, each terminal scalp hair usually grows continuously for about approximately three to five years. Then, the hair transitions into a resting state where the visible portion above the skin is shed. No hair grows from the follicle for 90 days. Once this time has passed, a new hair begins growing through the skin and continues for another three to five years at a rate of approximately 1/2 inch per month.
It is thought that as many as 100 genes are involved in regulating the creation, construction and cycling of scalp hair. To date, very few of these genes have been identified.
Common Pattern Hair Loss
Hamilton-Norwood Hair Loss Scale
For those concerned about hair loss, many myths and half-truths abound, but useful information can be difficult to obtain. Therefore, an objective overview of pattern hair loss is presented herein.