Please read the following reader friendly notes carefully before embarking on your chosen hair growth strategy.
Hair Growth
Hair consists of long keratin fibres, twisted rope-like and protected by an outer coating of keratinised cells. A cluster of active cells known as the dermal papilla lies just below the surface of the skin and it is from here that the hair fibre grows in its follicle or shaft.
The growing fibre becomes hardened to form the final hair structure which extrudes from the scalp. At this point the hair fibre is dead with only the root tip exhibiting living, growing cells. The number of dermal papillae is determined at birth as the body cannot produce additional clusters.
The hair growth cycle is characterized by three main stages:
1. Anagen stage - this is a fixed phase of growing that usually lasts between two and seven years. The average rate of growth is about six inches (15cm) per year with all hairs growing at roughly the same rate, depending on one's age, health and genetic make-up.
2. Catagen stage - this is a phase of transition lasting for roughly two to four weeks. At this time the hair shaft becomes detached from the dermal papilla and moves upward within a contracting follicle.
3. Telogen stage - this resting period lasts about three months allowing the hair to detach itself from the follicle prior to falling out. At this point the cycle repeats itself.
The shedding of hairs is therefore a natural process with anything from 100 to 300 hairs randomly shed from the scalp each day.
The influence of genetics
The dominant factor affecting hair growth is the genetic program that gives a particular hair follicle a predisposition to grow a new hair, or to stay in the resting phase and not grow hair. The cells that contain each individual follicle will possess a pre-determined set of instructions that is initiated and controlled by hormones released by the various glands in the body.
The cells that make up our body communicate with each other through hormones. The specialist cells in hair follicles have receptors for certain types of hormone messages that initiate a pre-programmed response. All normal men and women produce what are known as male hormones, the most common ones being testosterone, androsteinedione and dihydrotestosterone (DHT). These hormones have a useful role to play in both sexes but occur in different concentrations. The fact that androgens occur in much higher concentrations in men explains why this form of hair loss is much more common in men than in women.
The effect of these hormones on hair follicles is as follows:
1) High levels of an enzyme called 5-alpha-reductase occur in certain cells of the hair follicle and sebaceous glands.
2) 5-alpha-reductase converts testosterone into DHT.
3) DHT causes a process of miniaturization of the robust terminal hairs.
4) This leaves fine, short, less pigmented vellus hairs that provide inadequate scalp coverage.
5) The growth phase becomes progressively shorter until these hairs are lost for good.
Natural progression of hair loss:
At birth humans are covered with varying amounts of soft, fine body hair that is vellus in nature. Through time some of this hair becomes the more robust terminal type that may change color and texture. At puberty the hairline is characterized by its low, flat spread across the forehead but this persists only for a few years.
As men progress through their twenties the hairline assumes a more mature look with slight front-temporal recessions. This gives a concave appearance to the hairline on each side with a lower peak in the middle, as illustrated in Norwood Scale Number II Classification below. A hairline is considered to be balding only when the pattern resembles that illustrated in Norwood Class III.
The Norwood Scale is an extremely useful tool in developing your hair growth strategy as it allows you to establish your own degree of hair loss in a way that is understood by experts in the field of hair loss treatment. Most importantly, it can help you to differentiate between normal hair loss that does not require urgent remedial action, and more extreme loss that does require immediate treatment.
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