What causes hair loss?

The cause for either male or female pattern hair loss -- can be broken down in three parts. First, is any of the various hormones that control the appearance and development of masculine characteristics such as testosterone. The second is genetic - the inheritance of genes from either the mother of the father's side of the family. The third is age, which when coupled with genetics, represents a time clock that will signal the hair follicle to produce an enzyme named 5 alpha reductase. When the testosterone present in the follicle combines with the enzyme 5 they produce dihydrotestosterone (DHT). Hair follicle receptors are sensitive to DHT and thereby start the process of male or female hair loss. Over time, the action of DHT causes the hair follicle to degrade and shortens the anagen phase. Though the follicle is technically still alive and connected to a good blood supply - it will grow smaller and smaller. But, an important fact is, it can successfully nurture a transplanted follicle which is immune to the effects of DHT.

Male Pattern Baldness (MPB)

Common signals of MPB include a receding hairline and/or moderate to extensive loss of hair, especially on the crown. MPB is the hair loss most frequently encountered. It usually starts with the hair at the temples, which gradually recedes to form an "M" shape. You also may find your hair is finer and does not grow as long as it once did. The hair on the crown of your head begins to thin out and eventually at the top points of the "M" meet the thinned spot on your crown. Over time, you are left with a horse-shoe pattern of hair around the sides of your head. Any remaining hair in the balding areas usually manifests some miniaturization - it is thinner and grows at a below-normal rate, changing from long, thick, coarse, pigmented hair into fine, unpigmented sprouts.

Female Pattern Baldness (FPB)

Common signals of FPB include a general thinning of the hair all over the head and/or moderate loss of hair on the crown or hairline. FPB usually begins about age 30, becomes noticeable around age 40, and may be even more noticeable after menopause. Female hair loss is usually an overall thinning - two hairs where five used to be - rather than a bald area on top of the head, though women may have a receding hairline, too. It's thought that about 20 million American women have such hair loss. As in males, hair follicles simply shut down, with hormones playing some role in the process.