Causes of Female Hair Loss

Alopecia is the medical term for hair loss and the major cause of alopecia is genetic in origin. Hair loss is the result of the interaction of certain hormones circulating throughout your blood cells with the hair follicles themselves. Each individual's genetics determines how this interaction takes place and, subsequently, how much hair loss an individual experiences. Testosterone, which is a hormone present in both men and women, is converted to DHT by a chemical reaction in the blood stream, and when DHT binds to receptor sites on the hair follicle, that hair follicle becomes thinner and smaller, and eventually dies.

Hormonal imbalance in women can result in hair loss. Although hair loss in women usually stems from the same causes as men, it manifests itself differently and is more complex than hair loss in men. Women typically have a diffuse pattern of hair loss (all-over thinning rather than one balding area) that is more difficult to treat. Additionally, while men typically have areas of hair at the back of the head that are genetically programmed to resist balding and are therefore suitable “donor” hairs for hair transplant surgery, sometimes the donor area in women is also involved; therefore, transplanted hairs in this case may eventually fall out. Although many women are good candidates for hair transplantation, because of these issues, it is very important that women receive a thorough evaluation and counseling before proceeding with a hair transplant.

Hair growth is cyclical. Each hair goes through three cycles many times during a person's lifetime. Anagen is the active growing phase of hair growth, and it lasts three to ten years. At any one time, approximately 90% of your hair is in the anagen phase. The second phase is the catagen phase, during which time the hair regresses. This phase lasts between two-to-three weeks, and is followed by the telogen or "resting" phase. In the telogen phase the hair shaft is hibernating, but the living cells are alive beneath the scalp. The telogen phase lasts between three and four months, and then a new anagen cycle begins again.

At any one time, approximately 10% of the hairs on your head are in the resting phase, but many different factors, such as stress, surgery, medication, or medical illnesses, can cause a larger percentage of hair to enter the telogen phase. This is very important, as the thinning that accompanies this "telogen effluvium" should correct itself.