Can we re-activate hair growth? Jose Luis Pelaez Inc/Getty

Hairs all over the body use the same two chemical signaling pathways to communicate with each other – a finding that might help us better understand baldness.

Hair doesn’t constantly grow. Instead, each hair follicle goes through a cycle of growing, dying and resting. Previous research has found that two chemical signaling pathways called Wnt and BMP play a role in regulating when the hairs on the backs of mice grow.

Now Maksim Plikus at the University of California, Irvine, and his team have used mathematical modelling to see if WNT-BMP signaling might play a role across the whole body. They found that waves of Wnt and BMP signaling can accurately explain the growth cycles of all the hairs on a mouse.


This suggests that hairs all over the body use the same chemical language to coordinate each others’ growth. Waves of Wnt signaling spreading from hair to hair activate follicle growth, followed by waves of BMP signaling that shut down the stem cells in these follicles, halting growth.

Fighting hair loss

“Think of it like in track and field when people run and pass the baton,” says Plikus. “One runner is an active hair follicle and is passing off an activating signal to another hair follicle.”

This is the first time a model of many hair follicles has accurately predicted growth patterns across an entire mouse. The team based their model on observations of Wnt and BMP signaling in smaller areas, and extended it to cover the whole body. The model predicted certain patterns of growth which the team were then able to identify in real mice.

Plikus hopes to use similar models to inform efforts to regulate the Wnt-BMP system with drugs – an approach that may spread waves of growth back into balding areas.

“We now have a road map to optimise the levels of activators and inhibitors to achieve desired hair growth,” says Plikus.

Journal reference: eLife, DOI: 10.7554/eLife.22772

Read more: 3D drops raise hopes of cure for baldness