More than 40 percent of men in the U.S. will show signs of male-pattern baldness sometime between the ages of 18 and 49. But studies looking at the genomes of this group of men have failed to turn up a genetic cause, which makes a true cure seem an unlikely prospect.  

Treatments for male-pattern baldness, also known as androgenic alopecia, may be forthcoming, however. Recent work is homing in on three types, including one that was reported in March in the journal Science. In the new paper, George Cotsarelis of the University of Pennsylvania and his team found that a compound known as prostaglandin D2 (PD2) was elevated in the blood of men with male-pattern baldness. When they blocked PD2 receptors in mice, they ensured that the hair did not stop growing. Those blockers could be applied topically, Cotsarelis says.

He is also working on growing new hair. Researchers have noticed that if you wound a mouse, the animal generates new hair follicles as part of the healing process. The new follicles come from skin cells that turn into hair follicles through what is called the Wnt-mediated signaling pathway. It is the same pathway that helps you generate new hairs naturally as they fall out. Cotsarelis is working with a company to replicate that process.

A third approach, called follicular neogenesis, would allow doctors to remove, multiply and then reimplant the stem cells found inside a person’s hair follicles. So far, though, when researchers remove the stem cells and culture them, the cells appear to “forget” they were ever hair cells. Researchers are now attempting to figure out how to restore their “memory.”

As scientists continue to search for treatments to androgenic alopecia, they recommend patience. “People think of it like growing grass or something, but it’s nothing like that,” Cotsarelis says. “It’s like trying to treat cancer; it’s a complicated process.”

This article was published in print as "It's Not "Like Growing Grass"."