🔬 Contrary to previous belief, hair does not "grow"

The growth of our hair may follow a logic contrary to common understanding. For decades, scientists believed that hair was simply expelled from the follicle. A recent publication radically changes this view by highlighting an active pulling mechanism.

Thanks to a three-dimensional imaging technique that allows the observation of moving cells in real-time, teams from L'Oréal and Queen Mary University of London monitored the dynamics of cultured human hair follicles over an extended period. This unique observation window provided insight into the biological processes.


The observations thus showed that cells of the follicle's outer root sheath perform descending spirals while producing an upward-oriented force. The authors propose that this movement acts like a tiny motor, actively pulling the hair outward. To confirm this hypothesis, experiments blocked cell division without interrupting growth, while disrupting proteins like actin slowed the process by more than 80%.

Consequently, this revision of follicular mechanics opens perspectives for understanding hair disorders. It directs research towards treatments targeting not only biochemistry but also the physical environment. This lead could even have repercussions on regenerative medicine, beyond hair loss alone.

The imaging method used now allows for real-time evaluation of compounds' effects on living follicles. This advance accelerates work by providing a model more representative of biological reactions. The goal is to design more effective therapies by acting on the internal forces of tissues.

Published in Nature Communications, this work constitutes a notable advance. It encourages reconsidering the foundations of hair growth and exploring new therapeutic approaches, with potential applications extended to health.