That’s why stress makes your hair fall out

Harvard University scientists say they may have figured out how stress can make us lose our hair. In mice, they found evidence that a major stress hormone made hair follicle regeneration more difficult. The results could very well lead to more effective hair loss treatments someday, although more research remains to be done.

There is a lot of proof link stress to a higher risk of losing your hair. Sometimes, it is even believed that a traumatic event in life triggers acute episodes of hair loss, a condition called telogen effluvium. And over the past year, experts have speculated that pandemic stress contributes to greater hair loss, even among people who have not contracted covid-19.

Cortisol, commonly known as the stress hormone, is one of the main causes of stressful hair loss. This new study, published in Nature on Wednesday tried to unravel the possible causes of cortisol-related hair loss. They experimented with mice because they produce a very similar stress hormone called corticosterone (this the hormone is also produced by humans in small amounts, but it does not play a major role in our stress response).

Hair follicles, which give birth to the luxurious locks of hair that grow out of our scalp, normally undergo two main phases of activity: a phase of growth and rest. During the growth phase, the stem cells of the hair follicles mature, which regenerates the follicles and allows new strands of hair to grow. In the resting phase, the stem cells remain dormant, and, in the end, the strands of hair from these follicles disappear. Normally, when our hair is about to fall out, a new strand appears to replace it. But when the resting phase lasts longer than usual or the hair follicles just stop regenerating, we get hair loss.

In these mice, the researchers showed that chronic stress appeared to prolong the resting phase of hair follicle stem cells. They were also able to reproduce the same effect when they artificially dosed the mice with high levels of the stress hormone. And when they stopped the mice from producing the hormone, their hair follicles had very short resting phases and continued to function without any inconvenience, which allowed the mice to continue to grow hair even to an old age. advanced.

“This result suggests that high stress hormones do indeed have a negative effect on hair follicle stem cells,” said study lead author Ya-Chieh Hsu, stem cell researcher at Harvard, in a report. declaration published by the university.

The team’s previous work has also suggested that stress can to contribute at an early stagesmoothing our hair, possibly by affecting neighboring stem cells. But the effects of stress on hair loss and graying does not seem to be caused by the same thing.

Other experiments conducted by the researchers showed that the hormone appears to influence the dermal papilla, a group of cells just below the hair follicle that play an important role in the nutrition and regeneration of the follicle. In these cells, the hormone prevented them from producing Gas6, a molecule that could be essential in keeping our hair intact.

“Under normal and stressful conditions, the addition of Gas6 was enough to activate the stem cells in the hair follicles that were in the resting phase and to promote hair growth,” Choi said. “In the future, the Gas6 pathway could be exploited for its potential to activate stem cells to promote hair growth. It will also be very interesting to explore whether other stress-related tissue changes are linked to the impact of the stress hormone on the regulation of Gas6.

Mice are not people, of course. As interesting as these results are, it will take more time to determine whether the The same stress-related hair loss mechanisms also apply to us, and the question of whether Gas6 could be used to safely prolong hair growth in our later years. But if you’ve ever worried about hair loss, it seems like keeping your stress in check might be one way to keep your hair flowing.