What If Baldness Isn’t Permanent After All? Scientists Found What Actually Stops Hair from Growing—And How to Restart It
12th May 2025
Hair follicles go through repeated cycles of growth, rest, and shedding. At the heart of these cycles are hair follicle stem cells (HFSCs), which are responsible for producing new hair after the old ones fall out. In the new study, scientists discovered that these stem cells require a protein known as MCL-1 to function properly. When MCL-1 was deleted in mice, HFSCs quickly underwent stress and died. Without the stem cells, the process of hair regrowth halted completely.
In experiments where MCL-1 was removed from adult mice, researchers also shaved small patches of fur to test recovery. They found that in the absence of MCL-1, the shaved patches did not regrow any hair. In contrast, mice with normal MCL-1 expression experienced routine regeneration. This points to the protein’s essential role in maintaining healthy HFSC populations in adults.