A groundbreaking study has revealed a previously unknown network of cells that actively pulls hair out from its roots, challenging decades of textbook knowledge and offering potential avenues for hair-loss therapies.
Until now, scientists believed that hair emerged due to an upward push from dividing cells in the hair bulb. However, researchers using advanced 3D imaging have shown that hair is actually pulled upward by a coordinated network of moving cells in the surrounding tissue.
“For decades, it was assumed that hair was pushed out by the dividing cells in the hair bulb,” said Dr. Ines Sequeira of Queen Mary University of London. “We found instead that it’s actively being pulled upwards by surrounding tissue acting almost like a tiny motor.”
In the study, published in Nature Communications, scientists blocked cell division in the hair follicle, expecting hair growth to slow or stop. Surprisingly, growth continued at nearly the same pace. When they disrupted the protein actin—which allows cells to contract and move—hair growth fell by more than 80 percent, highlighting the protein’s key role in the process.
Computer simulations further confirmed that the pulling force generated by actin, coupled with coordinated movement in the follicle’s outer layers, drives the upward movement of hair. The research revealed a spiral-like downward migration of outer root sheath cells into the lower bulb region, which generates a pulling force contributing to hair extrusion.
Using advanced 3D time-lapse microscopy, researchers observed these intricate processes in real time, enabling them to model the forces generated within the follicle—insights impossible to glean from traditional methods.
“This approach made it possible to model the forces generated locally,” said Nicolas Tissot, a co-author of the study.
Experts say the findings could reshape the study of hair disorders and accelerate the development of treatments. “This new view of follicle mechanics opens fresh opportunities for studying hair disorders,” said Thomas Bornschlogl, another author.
The imaging technique also allows researchers to test drugs and treatments live, potentially fast-tracking the discovery of therapies for hair thinning and hair loss.
