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Women and Hair Loss: The Causes

Today more women than ever are experiencing hair loss -- and the causes may be quite different that what causes balding in men.
By Colette Bouchez
WebMD Feature

From Lady Godiva to the Breck Girl, Farah Fawcett to Jennifer Aniston, there is no question that, at least for women, hair is often a defining point in personal style. That's one reason why so many women panic at even the thought of losing a few hairs down the drain with each shampoo.

Those fears are not unfounded, as each year more women are forced to come to grips with the possibility of serious hair loss. According to the American Academy of Dermatology, it's a growing problem, affecting some 30 million women in the United States -- with some forms of loss occurring at earlier ages, and being seen in increasing numbers.

"I have seen women as young as 15 or 16 develop hair loss problems -- it's not common, but it's also not that rare," says Ted Daly, MD, a dermatologist from Nassau University Medical Center on Long Island, who specializes in the treatment of female hair loss.

But what exactly causes a woman to lose her hair? To understand that, it's important to know a little something about how hair grows.

Growth Cycle Interrupted

Experts say our tresses usually grow at the rate of about one-half inch per month -- with each hair having a growth phase of two to six years. At that point the hair "rests" for a period of time, then falls out -- and the follicle from which it sprang soon starts growing a new strand. And so the cycle continues, usually well into our senior years.

In some folks, however -- those with a genetic predisposition to hair loss -- a group of hormones called androgens interferes with this natural process. According to dermatologist Michael Reed, MD, androgen hormones include testosterone, androsteinedione, and dihydrotestosterone (DHT) -- all of which are made in men's bodies in large amounts, and in women's bodies in small amounts.

In those who are genetically susceptible, when testosterone comes in contact with enzymes residing in the hair cell, it is converted into the more potent androgen DHT, which then binds with receptors deep within the hair follicle.

"Over time, an excess build-up [of DHT] in the follicle causes it to begin shrinking, which in turn alters the natural resting and growth phases of the hair," says Reed, clinical associate professor of dermatology at NYU Medical Center, and a specialist in female hair loss. Some of the follicles eventually die, while others are rendered incapable of producing or maintaining healthy hair growth. The end result, says Reed, is hair loss -- and a condition that is medically known as androgenic alopecia.

For many decades, doctors believed that androgenic alopecia was the primary cause of balding in both men and women. Today they know this is not true -- at least where women are concerned.