Cause of male baldness put on scalp cells

PHILADELPHIA, Jan. 5 (UPI) -- U.S. researchers say they've discovered what they believe is the cause of male pattern baldness, pointing to the stem cells that create new hair.

Scientists at the University of Pennsylvania say a defect in the cells causes the hair that is produced to be so thin it appears invisible to the naked eye, creating a bald spot or receding hairline, the BBC reported Wednesday.

Researchers say restoring the normal function of the cells could eliminate the bald appearance.

The study found that although bald areas had the same number of hair-making stem cells as normal scalp, there were fewer of a more mature type, known as progenitor cells.

Because of that hair follicles in bald areas shrink and the new hairs produced are microscopic compared to normal hair.

"This implies that there is a problem in the activation of stem cells converting progenitor cells in bald scalp," research leader George Cotsarelis said.

"The fact that there are normal numbers of stem cells in bald scalp gives us hope for reactivating those stem cells," he said.