Scientists have discovered that hair does not grow because it is pushed out from the root. Instead, tiny cells inside the hair follicle pull the strand upward. This new idea changes what textbooks have taught for many years and may help new ways to treat hair loss.
How the Study Was Done
Researchers from L'Oréal and Queen Mary University used a special 3‑D camera that can watch living cells inside a human hair follicle kept alive in the lab. They saw that cells in the outer layer of the follicle move in a spiral path that goes downwards. This movement creates a pulling force that lifts the hair.
What the Experiments Showed
The team stopped the cells from dividing. Hair kept growing almost as fast as before, so cell division was not the main driver. Then they blocked a protein called actin, which helps cells contract and move. Hair growth dropped by more than 80 %. Computer models agreed that the coordinated motion of the outer cells is needed to match the speed of real hair growth.
Why It Matters
Even though the work was done on hair follicles grown in the lab, it gives fresh clues about how hair works and how we might fix hair‑loss problems. Knowing the mechanical forces inside a follicle could lead to treatments that target both the physical and chemical environment of the hair. The new imaging method also lets scientists test medicines on living follicles.
Biophysics in Everyday Life
This research shows how tiny mechanical forces can shape the growth of body parts. It highlights the growing role of biophysics in modern biology.