Scientists have uncovered a new mechanism in hair growth that may change scientific textbooks and open doors for better hair treatment options. Traditionally, it was believed that human hair grew by being pushed up from the root as cells divided in the hair bulb. However, a recent study led by researchers from Queen Mary University of London discovered a complex network of cells that actively pulls the hair upward from the roots, acting much like a tiny motor within the scalp.
The team used advanced 3D imaging technology to observe living hair follicles in real time. Through this approach, they could see intricate cell movements and behaviors that were previously impossible to study. When cell division inside the follicle was blocked, hair growth continued nearly at the usual pace, surprising the researchers. But it was only when they disrupted the protein actin—responsible for cell movement and contraction—that hair growth slowed down drastically, declining by more than 80 percent.
Computer simulations supported the findings, showing that the actin-driven motion in the outer layers of the follicle creates a pulling force, which is crucial for moving the hair up through the scalp. The scientists observed that the outer root sheath cells spiral downward and enter the lower bulb region, suggesting a new model of how hair is physically moved upward.
The use of 3D time-lapse microscopy allowed scientists to visualize these processes as they happened, giving new insight into the dynamic forces at play in hair growth. According to Thomas Bornschlögl, a study author, the outer root sheath plays an active role in pulling the hair, not just providing structure. This shifts the focus from cell division to mechanical forces within the follicle.
Researchers believe this discovery could lead to more effective treatments for hair loss by targeting the mechanical aspects of the hair follicle, rather than focusing solely on cell division. The technique developed for the study also allows live testing of drugs and treatments, offering hope for advances in hair treatment, tissue engineering, and regenerative medicine. The new mechanistic understanding opens up opportunities for developing therapies for various hair disorders and improving treatment outcomes.
