Scientists announced Friday they have uncovered the bald truth, teasing out the fine details of the causes of hair loss.

"We've found the biochemical regulation mechanisms that control the process," declared Dr. Marty Sawaya, a dermatologist at the University of Miami School of Medicine, to a convention of the Society for Investigative Dermatology.Understanding the chemical changes in scalp cells that lead to baldness could pave the way for new medical treatment to stop hair loss, Sawaya said. She and a team of researchers found that two proteins on the outside of hair follicles and oil gland cells determine whether a patch of scalp is hirsute or hairless.

The smaller protein of the pair is the culprit in the balding process while the larger one blocks hair loss, Sawaya explained. The ratio of the proteins decides whether hair stays or goes.

Testosterone, a male hormone, binds to the small receptor protein and slips inside the nucleus of cells, stopping hair growth. The large protein, which also binds the hormone, is too big to pass into nuclei, allowing more growth.

"If we can regulate the ratio of smaller protein to larger, then maybe we can stop hair from falling out," Sawaya said.

In other research, the University of Miami team found a third protein inhibits testosterone from binding to the small protein.

Sawaya said she hopes in future research to make antibodies for the newly discovered proteins that could block the balding process.