Scientists believe they've found a potential new cure for baldness, thanks to a drug that treats osteoporosis.
Researchers from PLOS Biology have found the drug, Cyclosporine A, has a dramatic effect on hair follicles and stimulates growth when studied on male hair-transplant patients.
The drug contains a compound called SFRP1, a protein which blocks molecular pathways for hair growth.
Due to its side effects, researchers opted not to use Cyclosporine A but instead used compound WAY-316606 in a test drug to stop a protein that blocks hair production.
According to them, it is a "promising new promoter of human hair growth", better than what Cyclosporine A offers.
Dr Nathan Hawkshaw, who led the project, told the BBC the drug could "make a real difference to people who suffer from hair loss".
The drug's next step will be a clinical trial to determine whether it is safe.