When discussing baldness, which affects an estimated 40 million men and 20 million women in the United States, the topic is generally about a hereditary condition called androgenetic alopecia. Ninety-five percent of hair loss is of this variety.

Male-pattern baldness refers to the upward retreat of the hairline from the forehead, as well as an expanding area of fallout from the crown of the head. In the end, all that might be left is a horseshoe-shaped fringe around the sides and back of the head. Female-pattern baldness, which recently has received more attention since Pharmacia& Upjohn began packaging and marketing Rogaine separately for women, refers to a diffuse pattern of hair loss throughout the scalp.

Research continues in search of ways to treat androgenetic alopecia and allow hair to sprout in barren scalps. But, at this time, all you can do, if you're a man, is to look at your father's head and your mother's father's head to see how they fared, because chances are you'll wind up with a similar fate. In addition, female-pattern baldness can be passed down from mother to daughter.

"I think it's just the luck of the draw what your genetics are," says Allan Kayne, M.D., a dermatologist and assistant clinical professor of medicine at the University of Washington Medical Center in Seattle.

In male- and female-pattern baldness, the culprit is something called dihydrotestosterone, or DHT, which is derived from androgen, a male hormone. Circulating through the bloodstream, androgen is converted to DHT by the enzyme 5-alpha reductase. Those with greater enzyme activity have more DHT binding to hair-follicle receptors. If flooded by DHT, the follicles sprout thinner and thinner hairs until nothing regrows, and the follicles eventually wither away.

Hair Replacement
Minoxidil
Surgery
Hairpieces
Health-Related Hair Loss
Mythical Treatments For Hair Loss
The Thick and Thin of Hair Cosmetics
More Information About Baldness