Scientists have found that human hair growth does not grow by being pushed out of the root; it’s actually pulled upward by a force associated with a hidden network of moving cells. The findings challenge decades of textbook biology and could reshape how researchers think about hair loss and regeneration.

The team, from L’Oréal Research & Innovation and Queen Mary University of London, used advanced 3D live imaging to track individual cells within living human hair follicles kept alive in culture. The study, published in Nature Communications, shows that cells in the outer root sheath—a layer encasing the hair shaft—move in a spiral downward path within the same region from where the upward pulling force originates.

Dr. Inês Sequeira, Reader in Oral and Skin Biology at Queen Mary and one of the lead authors, said, “Our results reveal a fascinating choreography inside the hair follicle. For decades, it was assumed that hair was pushed out by the dividing cells in the hair bulb. We found that instead that it’s actively being pulled upwards by surrounding tissue acting almost like a tiny motor.”

University of Pittsburgh researchers have made an important step toward providing hospitals and water treatment facilities with a safer, greener alternative to chlorine-based disinfection.

The team, which includes scientists from Drexel University and Brookhaven National Laboratory, uncovered key design principles for catalysts that can generate ozone, a disinfecting agent, on demand. The research is published in the journal ACS Catalysis.

This breakthrough addresses a critical challenge in water sanitation. Chlorine, commonly used to kill bacteria on surfaces and in water—including most municipal drinking water—is hazardous to transport and store, and its byproducts can be carcinogenic. These risks limit its use and motivate the search for safer disinfectants.