It's Not "Like Growing Grass"; June 2012; Scientific American Magazine; by Rose Eveleth; 1 Page(s)

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.