Forget what you know about hair growth. New research reveals hair isn’t pushed but pulled by moving cells in the follicle. Discover the science that could change hair loss treatments.
New research reveals that human hair doesn’t grow by being pushed outward from the root, as previously believed. Instead, hair is actively pulled upward by a network of moving cells within the hair follicle. This discovery challenges long-standing assumptions in biology and could reshape how scientists approach hair growth, loss, and regeneration.
Researchers from L’Oréal Research & Innovation and Queen Mary University of London used advanced 3D imaging to observe individual cells in living human hair follicles. Their findings show that hair isn’t simply pushed out by dividing cells in the hair bulb. Instead, the outer root sheath, surrounding the hair shaft, contains cells that move in a spiral downward motion, creating a pulling force that brings the hair upward. The research was published in Nature Communications.
Cellular ‘Motor’ Inside the Follicle
Dr. Inês Sequeira, a Reader in Oral and Skin Biology at Queen Mary, 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.”
To test their theory, the team blocked cell division in the follicles, expecting hair growth to stop. Surprisingly, the hair kept growing almost as usual. But when they interfered with a protein called actin, which allows cells to contract and move, hair growth slowed by more than 80%. The team used a new imaging technique called 3D time-lapse microscopy which helped them see live hair follicles in action, showing how cells move and interact in real time.
Dr. Thomas Bornschlögl, another lead author, added that the outer root sheath plays an active role in pulling hair upwards. This new understanding could help us study hair disorders, test new treatments, and advance tissue engineering and regenerative medicine.
Mechanism Behind Human Hair Growth
Although the study was carried out on follicles in the lab, it provides new insights for hair science and regenerative medicine. By understanding the mechanical forces that drive hair growth, researchers could develop treatments that target not just the chemistry of follicles but also their physical environment. The imaging technique may also allow live testing of drugs and therapies.
Overall, the study highlights how tiny mechanical forces at the cellular level can shape the organs we see every day, showing the growing importance of biophysics in biology.