Hair Growth Mystery Solved: Hair Pulled, Not Pushed, by Follicle Cells

For decades, biology textbooks have described hair growth as a relatively straightforward process: new cells divide at the base of the hair follicle, pushing older cells upward and outward. But a recent discovery, published in Nature Communications on March 14, 2026, challenges this long-held assumption. Scientists at L’Oréal Research & Innovation and Queen Mary University of London have found that hair isn’t pushed out at all – it’s actively pulled upward by a hidden network of moving cells within the follicle. This finding could reshape our understanding of hair loss and regeneration, and open new avenues for treatment.

A New Understanding of Follicle Dynamics

The research team employed advanced 3D live imaging techniques to observe individual cells within living human hair follicles maintained in a laboratory setting. This allowed them to track cellular activity in real-time, revealing a surprising choreography. Cells in the outer root sheath – the layer surrounding the hair shaft – move in a spiral downward path. Crucially, this downward movement occurs in the same region where the upward pulling force originates. As Dr. Inês Sequeira, Reader in Oral and Skin Biology at Queen Mary, explained, “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.”

This isn’t simply a refinement of existing knowledge; it’s a fundamental shift in how scientists view hair follicle mechanics. The team’s work suggests that the follicle isn’t a passive tube through which hair is extruded, but rather a dynamic structure with an internal “pulling engine.”

Testing the Conventional Model

To validate their findings, the researchers conducted a series of experiments designed to test the traditional “push” model. They first blocked cell division within the follicle, anticipating that hair growth would cease if dividing cells were indeed responsible for pushing the hair upward. Surprisingly, hair continued to grow at nearly the same rate, even without cell division. This suggested that cell division, whereas important for follicle health, isn’t the primary driver of hair elongation.

The pivotal experiment involved interfering with actin – a protein essential for cell contraction and movement. When actin function was disrupted, hair growth slowed dramatically, decreasing by more than 80 percent. This demonstrated that the coordinated movement of cells, facilitated by actin, is critical for generating the pulling force that drives hair growth. Computer models further confirmed that this force, correlated with the spiral motion in the outer layers of the follicle, was essential to match the observed speeds of hair movement. Queen Mary University of London provides further details on the study’s methodology.

The Role of Advanced Imaging

The breakthrough was made possible by the development of a novel imaging method that allows for 3D time-lapse microscopy in real-time. Dr. Nicolas Tissot, from L’Oréal’s Advanced Research team, emphasized the importance of this technology: “We use a novel imaging method allowing 3D time lapse microscopy in real-time. While static images provide mere isolated snapshots, 3D time-lapse microscopy is indispensable for truly unraveling the intricate, dynamic biological processes within the hair follicle, revealing crucial cellular kinetics, migratory patterns, and rate of cell divisions that are otherwise impossible to deduce from discrete observations.” This approach allowed researchers to observe the intricate cellular movements that were previously hidden from view.

Implications for Hair Loss and Regeneration

The discovery has significant implications for understanding and treating hair loss. For years, research has focused on stimulating cell division in the hair bulb as a means of promoting hair growth. While this may still be important, the new findings suggest that targeting the mechanisms responsible for the pulling force could be equally, or even more, effective. Dr. Thomas Bornschlögl, as well from L’Oréal’s research team, noted that this reveals “hair growth is not driven only by cell division — instead, outer root sheath actively pull the hair upwards.”

Understanding the physical forces within hair follicles could lead to the development of new therapies that address both the mechanical and biochemical environment of the follicle. The researchers also believe that the new imaging approach could be used to test potential drugs and therapies on living follicles, accelerating the drug discovery process. ScienceDaily reports on the potential for future treatments.

Biophysics and the Future of Biological Research

This study highlights the growing influence of biophysics in modern biology. Traditionally, biology has focused on the chemical and genetic processes within living organisms. However, increasingly, researchers are recognizing the importance of physical forces in shaping biological structures and functions. The hair follicle study demonstrates how microscopic mechanical forces can have a profound impact on a seemingly simple biological process. Science News Today provides a broader context for this shift in research focus.

What’s Next for Hair Follicle Research?

The research team plans to continue investigating the mechanisms responsible for the pulling force, with a particular focus on the role of actin and other contractile proteins. Further studies will be needed to determine whether these findings translate to different hair types and ethnicities. Researchers will explore the potential for developing new therapies that target the outer root sheath to stimulate hair growth. The team also intends to refine the 3D imaging technique to provide even greater detail of the dynamic processes within the hair follicle. Ongoing research will also focus on how disruptions to this “pulling engine” contribute to various forms of hair loss, paving the way for more targeted and effective treatments.