A recent study suggests that graying hair might be the body’s natural defense mechanism against skin cancer.

Scientists at The University of Tokyo explored the connection between hair graying and melanoma, a severe form of skin cancer that impacts over 200,000 people in the U.S. every year.

Both the graying of hair and the development of melanoma involve melanocyte stem cells (McSCs), which are responsible for producing the pigment in hair and skin.

When the melanocyte cells in hair follicles become depleted or lose their functionality, pigment production reduces, resulting in gray hair.

In their research, scientists examined how McSCs in the hair follicles of mice responded when exposed to cancer-inducing chemicals.

The study found that when McSCs were damaged, some cells died, causing hair to turn gray. This phenomenon is attributed to a process known as the p53-p21 pathway.

This specific pathway is a tumor suppressant and is considered the ‘guardian’ of human genes because it protects against DNA damage from outside stressors. 

From these findings, the investigators believe gray hair might reflect a mechanism in which the body removes damaged stem cells before they can turn cancerous. 

Going gray could reflect someone’s natural defense capabilities against cancer, according to a new study (Stock image)

However, not all cells follow this process, and those that don’t could turn malignant.

Dr David Sinclair, a professor in the department of genetics at Harvard Medical School who was not involved in the study, told the Daily Mail that the findings could help shape preventative treatments for melanoma and some other cancers.

‘The University of Tokyo study’s finding that hair graying may reflect the body’s defense against cancer is fascinating,’ he said.

‘It suggests the loss of pigment could be a way of protecting against damaged cells turning cancerous. 

‘If we can learn how gray hair could protect against cancer, like the study suggests, we might unlock new ways to stop melanoma before it starts.’

While there is no ‘normal’ age at which a person’s hair starts to go gray, some studies suggest that the overall average is in a person’s early 40s. 

However, it is not uncommon for people to see their first gray hairs in their 30s – and exposure to cancerous toxins isn’t the only cause.

As people age, the melanocyte stem cells in hair follicles naturally begin to diminish, which reduces melanin production and causes hair to lose its color. 

The most significant factors in hair graying are genetics and aging. But stress can still play a role.

Stress-related graying can occur as hair pigmentation is influenced by melanocyte stem cells, which are sensitive to stress hormones like cortisol. 

When stress is high, these cells may stop functioning properly, leading to gray hair. But if the stress is removed early enough, and the cells are not permanently damaged, they may resume pigment production, restoring color.

A 2021 study from Columbia University and the University of Miami found that some people’s hair regained its natural color after stress was reduced. 

While some people see graying as a negative, the Tokyo study, published online in the journal Nature Cell Biology, suggests it could be a positive trait, and a sign of overall resilience against disease. 

‘These findings… reframe hair graying and melanoma not as unrelated events, but as divergent outcomes of stem cell stress responses,’ Lead author Professor Emi Nishimura said in an accompanying press release.

Pictured: A graph showing cancer prevalence and projections in the US from 1975 to 2040 by age

And while many opt to cover their gray hairs with dyes, recent research has found a range of hair care products – including some colorings – contain the chemical formaldehyde, which may cause cancer. 

Formaldehyde, used in hair products as a preservative, can escape as a gas over time through a process known as ‘off-gassing’ – especially when they come into contact with heat.

If these fumes are inhaled repeatedly, they can lead to anything from minor side effects like eye and respiratory irritation to major health issues like an increased risk of head and neck cancers. These risks are heightened if an area like a bathroom or bedroom is poorly ventilated. 

Formaldehyde exposure has also been linked to melanoma.

Studies show it can increase the proliferation of melanoma cells in a lab setting, and there are documented cases of nasal cavity melanomas in workers with long-term formaldehyde exposure. 

The Cleveland Clinic warns that melanoma is the most dangerous type of skin cancer, saying it grows quickly and has the ability to spread to any organ. 

In 2025, it is estimated that about 212,200 cases of melanoma will be diagnosed in the US, resulting in more than 8,000 deaths.

The best way to catch it early is through examining your skin monthly to look for new or changing moles, and getting regular professional skin exams from a dermatologist.