Hair loss can also be stress-related

How stress leads to gray hair – and what helps against it

“I know someone who got gray hairs during her bachelor’s thesis!” – What sounds like an urban legend that is told between eating in the canteen and visiting the library was actually proven by researchers at Harvard University in experiments with mice: stress can cause gray hair.

To investigate this, the researchers repeatedly tilted the mice’s cages, turned the light on and off, or administered resiniferatoxin – a drug that causes pain. The mice reacted stressed: stress hormones such as adrenaline and cortisol were released, their heart beat faster, blood pressure rose and the nervous system was stimulated. And after a while, the fur of the mice also turned gray in places on the abdomen and back due to the acute stress. The research team led by Ya‑Chie Hsu, Professor in the Department of Stem Cell and Regenerative Biology at Harvard University, published these results. in the journal Nature. But why does the hair turn grey?

How stress affects hair

The researchers found the cause of the graying fur in the autonomic nervous system, namely in the sympathetic nervous system. The nerve cells of the sympathetic nervous system lie in the middle of the spinal cord, between the cervical, thoracic and lumbar cords. When there is stress, hormones such as adrenaline, noradrenaline and cortisol are released from there, which ensures that the body is very willing to perform. Basically, this enables the famous fight-or-flight response: living beings are able to fight or flee in risky situations. But norepinephrine also seems to have an unsightly effect for many people.

As the researchers found out, noradrenaline also reaches the smallest human organs via nerve tracts: the hair follicles. Hair follicles are made up of several types of cells and surround the hair root. Norepinephrine acts there on so-called melanocyte stem cells. These are necessary for the formation of new melanin cells, which in turn are crucial for the coloring of the hair. When there is stress, melanin is produced excessively, which means that there may not be any stem cells left to produce new melanin. The hair that grows back then has no color pigments – and appears gray to us. Does the same happen to stressed students during their thesis?

It is not entirely clear to what extent the results can also be transferred to humans. The results “suggest that norepinephrine induces similar responses in melanocyte lines from humans and mice,” suspects Hsu’s research team.

Stress can also cause hair loss

And something else the scientists were able to confirm through experiments with mice: stress can lead to hair loss. However, this is based on a different biochemical process than in the case of stress-related gray hair. The stress hormone corticosterone, which is produced in the adrenal cortex, is largely responsible for hair loss.

For their experiments on mice, the researchers removed the adrenal glands from some rodents – and injected another group of mice with the stress hormone for weeks. In fact, hair growth was stimulated in mice without adrenal glands, but hair growth slowed down or fell out in overly stressed mice.

Can we prevent “stress hair”?

Scientists now know how stress affects hair color and fullness – at least in mice. It remains open: is this knowledge really applicable to humans? And if so: How can stress-related graying and hair loss be prevented? The research on this is not yet complete.

While Hsu and her team believed stress-induced graying in mice was irreversible, this for the people another study, which was carried out by researchers from Columbia University, among others. With the help of stress diaries and hair samples from several people, the researchers measured the connection between stress intensity and hair graying: the small sample found a positive connection – and also cases in which gray hair turned back with less stress.

How much mouse is in a human?

The authors of the study doubt that humans and mice are similar in terms of their hair functions. “Mice have a very different hair follicle biology, and this could be an example where the results in mice don’t translate well to humans,” says co-author Dr. Ralf Paus, Professor of Dermatology at the University of Miami Miller School of Medicine. Her research suggests that when people are stressed and hair color changes, changes occur in 300 proteins.

In humans, they blame the power plants of the cells: mitochondria. “Mitochondria are actually like little antennas in the cell that respond to a variety of signals, including psychological stress,” says Martin Picard, author of the study and a professor at Columbia University.

Anyone who has gone completely gray due to age will probably not regain their original hair color in a hurry – at least not without hair dye. But individual gray hairs caused by stress could possibly return to their original color once calm returns. Can you help with medication?

So far no medication for graying and hair loss

There are (still) no research results for humans. However, a research team from China has been looking for a preventive agent for stress-related graying in mice. With success: They found that isoliensinin can prevent stress-induced hair graying in mice. The active ingredient prevents norepinephrine from affecting the melanocyte stem cells. “The study sheds light on the development of products that use natural compounds to prevent stress-related hair graying,” the researchers summarize. The specialist article on this was published at the end of March 2023 – so the research is still in its infancy. It might not be that far with a cure for stress-related gray hair – but for the time being only for rodents.

There are also initial indications of how to counteract stress-related hair loss in mice. Hsu’s team injected mice with the protein Gas-6. “Under both normal and stressful conditions, the addition of Gas-6 was sufficient to activate dormant hair follicle stem cells and promote hair growth,” said Sekyu Choi, lead author of the study. But even here it is still unclear whether stress-related hair loss occurs in humans in the same way as in mice.

It will therefore still be some time before there are medications for treating graying hair and hair loss due to stress. Until then, stressed people can rely on tried-and-tested means for well-being from the little toe to the root of the hair: Sport, relaxation techniques such as yoga or breathing exercises, holidays and restful sleep are proven to be effective means of stress relief – and are already available without a prescription.