Hair Loss and Its Causes

Male pattern hair loss is an inherited condition, caused by a genetically determined sensitivity to the effects of dihydrotestosterone (DHT). DHT shortens the growth, or anagen, phase of the hair cycle, causing miniaturisation of the follicles, and producing progressively finer hairs until it eventually disappears.

There are other problems that can cause hair loss such as: Treatments for conditions such as cancer can cause hair loss. Hormonal problems like an overactive and an underactive thyroid may have an effect on hair loss. Also some medicines like blood thinners, antidepressants, birth control pills and medicines used to treat cancer.

Androgenetic alopecia
The medical term for hair loss is alopecia. Pattern baldness (androgenetic alopecia), the most common type of alopecia, affects roughly one-third of men. The condition runs in families and has a strong genetic component to its causation. It is believed to be related to an excess of male hormones in the body. Androgenetic alopecia is the cause of over 95% of all pattern hair loss. This occurs in somewhat predictable stages, and is relentlessly progressive. This means that those with pattern loss will eventually progress from the early stages of loss to the advanced stages.

The normal life span for each hair is from three to six years. Each hair grows in a hair cycle that can be divided into three stages: the growing stage lasting from two to six years, the partial degeneration stage lasting between 10 and 14 days, and finally the resting phase during which time the hair is shed and there is an involution of the hair follicles lasting about one hundred days. This cycle of growth and loss is normal, and as long as the hair is replaced as quickly as it is lost, baldness does not occur, this is part of the hair renewal process. Excessive DHT shortens the growth cycle and extends the resting phase. The results are thinning hair, hair loss, no re-growth.

Treatment for Hair Loss
Finasteride is the only FDA-approved treatment for male pattern hair loss. Propecia interferes with conversion of testosterone to another hormone called dihydro-testosterone (DHT). DHT reduces hair follicle activity. Over time and under the influence of DHT, follicles sprout thinner hairs until no hair regrows. When Propecia blocks DHT production, thinning of hair ceases and a more normal growth occur. Clinical trials conducted on thousands of men have shown that after 2 years of use 66% of men showed increased hair growth. 30% of men showed a slight improvement, 31% moderate improvement and 5% great increase. 83% of men in the trial showed no further hair loss.