Hair Grows by Being Pulled, Not Pushed: Study
Get the Health newsletter
Daily health & science — research, biotech, public health, the studies worth knowing. Free.
- L'Oréal Research & Innovation and Queen Mary University of London used 3D live imaging to watch cells in the outer root sheath of human hair follicles travel along a spiral path, generating an upward pulling force on the hair shaft.
- The study, published in Nature Communications, found that blocking cell division inside the follicle barely slowed hair growth, but blocking actin — the protein that lets cells contract and move — cut growth by more than 80%.
- Dr. Inês Sequeira, Reader in Oral and Skin Biology at Queen Mary and a lead author, said the discovery overturns decades of textbook assumptions that dividing cells in the hair bulb push hair outward.
- Dr. Nicolas Tissot of L'Oréal, the first author, said the team's novel 3D time-lapse microscopy was indispensable for modeling the forces generated locally within living follicles in real time.
- The experiments were conducted on human hair follicles maintained in laboratory culture, and the authors say the imaging platform could be used to test drug candidates and therapies on living follicles.
- Lead author Dr. Thomas Bornschlögl of L'Oréal said the findings suggest hair growth is driven not only by cell division but by the outer root sheath actively pulling the hair upward, opening new avenues for tissue engineering and regenerative medicine.
Why it matters: By overturning the push-from-the-root model, the research redirects hair loss investigation toward the mechanical environment of the follicle as a therapeutic target. Blocking the actin protein cut growth by more than 80%, and the new 3D imaging platform gives scientists a way to screen drug candidates on living follicles in the lab before clinical testing.
Ask SkimNews
