Welcome back to Just Curious, Strong Women’s weekly series exploring all the random health and fitness questions you’ve always wondered about but never got the answers to.

This week, we’re looking into whether there’s any truth behind the belief that stress can turn your hair grey.

Trying to predict when and where you’ll go grey is nearly impossible. For some people it’s a very gradual thing, whereas for others it feels like it happens overnight. Primarily, we see it as a sign of ageing – as we get older, all of us will go grey at some point. But that’s not the only factor that decides when and why our hair starts to lose its colour.

It’s a commonly held belief that stress can play a role. If you’ve ever joked about your boss ‘turning your hair grey’, you’ll know what we’re talking about.

It makes sense; we already know that staying stressed for long periods of time can mess with everything from your gut to your reproductive system and skin, thanks to the fact that it can redirect energy and resources away from ‘unessential’ parts of the body.

So, is that the same story with our hair? Does that mean going grey early on in life is a sign of poor stress management? And could introducing a variety of relaxation techniques into your daily routine help to stave off premature greying? 

While the occasional stressful day won’t lead to greying hair (even if it might leave you feeling zapped of energy and mental strength), long-term, chronic stress from things like a troubled relationship, financial worries or job pressures can have a direct effect on our hair cells.

“Our bodies are programmed to release certain hormones – such as cortisol and norepinephrine – when we find ourselves under threat or feeling pressure,” explains consultant trichologist Eva Proudman. “It’s part of the natural, instinctive fight-or-flight response, but if that persists for long periods of time, the excess cortisol can take a significant toll on our bodies, including our hair.

“When we’re in survival mode, the brain prioritises the supply of blood and nutrients to cells and tissues that are vital, so non-essential cells – such as the melanocytes that dictate hair colour – become low priority. Over time, the melanocytes begin to malfunction and hair colour fades.” 

Of course, stress isn’t the only reason why our hair turns grey. It’s a natural process that happens to everyone, thanks to the way our melanocytes age as we do.

“As we age, the melanocytes start to fail,” Proudman says. “Hair doesn’t actually go grey – it becomes translucent, appearing grey because it reflects light from surrounding darker hairs.”

There are a couple of different terms to describe the way hair turns grey. Premature greying of hair (also known as PGH, canities or achromotrichia) is the term used to describe the onset of grey hair at an early age, which is defined as 20 years in white people, 25 years in Asian people and 30 years in Black people.

Developing a patch or streak of grey hair while the rest of your hair retains its natural colour also has a name – poliosis – and is a genetic condition. 

Some of the key factors that influence when and why you ‘go grey’ include:

1. Genetics

“Genetics play a major role in who we are and what we look like, and this is so true of hair. [Genes have] a significant influence on the timing of grey hair,” says Proudman. “So, if you notice grey hair at an early age, it’s often likely that your parents or grandparents also had early onset of grey hair too.”

2. Health conditions

“Some autoimmune conditions such as vitiligo have been associated with early greying of hair,” Proudman explains. “Research suggests that this is due to the melanocytes being more affected by oxidative stress. “A Vitamin B12 deficiency can also cause premature greying of the hair.”

3. Smoking status

“It’s long been acknowledged that smoking tobacco can speed up the rate at which you go grey, and, in more recent years, it’s become more likely that using an e-cigarette – aka vaping – isn’t any safer,” says Proudman.

“This is because toxins in cigarettes trigger oxidative stress, a biological process where unstable molecules in the body called free radicals – which are produced by smoking – attack and destroy healthy cells in the scalp that produce melanin, the pigment that gives your hair colour.”

4. Where you live

“Air pollution can also damage hair colour in much the same way as cigarette smoke does,” Proudman explains. “When inhaled and absorbed into the bloodstream, toxins such as diesel fumes can trigger oxidative stress – damaging healthy cells in the scalp, reducing their ability to produce the melanin needed to retain colour.”

While grey hair is by no means a bad thing, there are ways to slow down greying due to air pollution, Proudman adds. “If you live in a built-up area, washing your hair regularly – at least every other day – can get rid of polluted particles that could penetrate the hair and damage melanocyte cells in the scalp. You could also consider using an antioxidant-rich conditioner, that can help protect against toxic deposits that might speed up the greying process.”

5. Sun exposure

“Too much sun exposure isn’t just bad for your skin – it can also drain the colour out of your hair,” Proudman says. “Excess UV light triggers the same oxidative stress that smoking does, damaging melanin-producing cells in the scalp and speeding up the greying process. Studies show that UV rays also disrupt levels of keratin, a protein in hair that strengthens and protects it.”

6. Heat exposure

In a similar way to the sun, too much heat can wreak havoc on the cells on your head. “Most household hairdryers heat to between 20° C and 60° C. At the top end of that range, it’s enough to ‘bake’ not only the hair but the delicate melanin-releasing cells in the skin and hair follicles, turning off the supply of pigment to each strand of hair.” 

Images: Getty