Why Does Stress Really Cause Gray Hair: Scientific Research

“Stress causes hair grey” – we have been listening to this aphorism since our childhood. And now scientists at Harvard University have proven why and how stress is the biggest reason behind white hair, especially at a young age or before getting old.

The study, published in Nature, “Advances Scientists – knowledge of how stress can impact the Body”.

Over the past two decades, researchers have found preliminary evidence that stress plays at least a small role in initiating the greying process.

Over the long years, stories have connected stressful experiences with the phenomenon of hair greying.

But now, for the first time, Harvard University scientists have discovered exactly how the process plays out and affects the colour of our hair.

As per the research under Dr. Ya-Chieh Hsu, a professor of regenerative biology at Harvard University in Massachusetts, US, stress activates nerves that are part of the fight-or-flight response, which in turn causes permanent damage to pigment-regenerating stem cells in hair follicles. Let’s find out further is grey hair caused by stress.

Why Does Stress Cause Grey Hair: Scientific Reason 

Our hair colour is determined by cells called melanocytes, which are derived from melanocyte stem cells (MeSCs).

As people age, the supply of MeSCs is gradually depleted, causing pigmented hair to be replaced with white hair.

Though stress affects the whole body, here researchers first had to narrow down which body system was responsible for connecting stress to hair colour.

The team first hypothesized that stress causes an immune attack on pigment-producing cells.

However, when mice lacking immune cells still showed hair greying, researchers turned to the hormone cortisol. But once more, it was a dead end.

While previous studies have linked stress to premature and accelerated hair greying, the underlying mechanism has remained unclear.

Researchers at Harvard were studying the effects of pain on mice by injecting a toxin called resiniferatoxin when they discovered the rodents’ fur had turned white in just four weeks.

The researchers exposed the animals to various types of stressors, including pain, restraint and psychological stress, during different phases of hair growth.

Each stressor was found to cause depletion of MeSCs, eventually leading to the development of patches of white hair.

On further investigation, the authors found that stress-activated the sympathetic nervous system, triggering the release of a neurotransmitter called noradrenaline.

They found that noradrenaline caused MeSCs to eventually “move away” from the hair follicles, thereby leading to loss of colour.

The team then looked for genes whose expression was most altered during the stress experiments and narrowed it down to one that encodes a protein called CDK.

The Earlier Assumption Why Stress Causes Gray Hair

As per the researchers – Stress always elevates levels of the hormone cortisol in the body, so we thought that cortisol might play a role.

But when they removed the adrenal gland from the mice so that they couldn’t produce cortisol-like hormones, the hair still turned grey under stress, making this assumption wrong among them.

Sympathetic nerves branch out into each hair follicle on the skin. The researchers found that stress causes these nerves to release the chemical norepinephrine, which gets taken up by nearby pigment-regenerating stem cells.

How Stress Can Permanently Damage Hair?

The research revealed that, in the hair follicle, certain stem cells act as a reservoir of pigment-producing cells.

When hair regenerates, some of the stem cells convert into pigment-producing cells that colour the hair in our body.

Researchers found that the norepinephrine from sympathetic nerves causes the stem cells to activate excessively and then convert into pigment-producing cells, prematurely depleting the reservoir and making your hair grey even at a very young age.

Also Read: What Causes Grey Hair at a Young Age: Premature Hair Greying

As Dr. Hsu said they expected that stress was bad for the body – but the detrimental impact of stress that was discovered was beyond their imagination.

In fact, after just a few days, all of the pigment-regenerating stem cells were lost and once they’re gone, you can’t regenerate pigment anymore resulting in permanent damage.

To connect stress with hair greying, the researchers started with a whole-body response and progressively zoomed into individual organ systems, cell-to-cell interaction and, eventually, all the way down to molecular dynamics.

Yes, it is scientifically proven that stress really causes hair to turn grey but still, there are multiple reasons that affect your hair colour and its texture.

Hair fall and greying are affected also due to water or pollution level environment, your health condition, eating habits and lifestyle etc. So, my personal advice is don’t take the stress and stay tension-free to live a happy life.

Also Read: How to Check Your Fitness Level and Health at Home: 4 Steps

Sources: Bt.com, Dailymail UK & Nature