I once met a man who said he was 27 but had a full head of silver.
Oddly, his beard was bright red and when I asked him how long he’d been grey for, he said when he hit puberty, his hair began to turn.
Of course, I wanted to know why but like most of us, he had no idea.
New York Times writer Karen Weintraub wrote that when cells called melanocytes found at the base of each hair follicle get damaged by disease, environmental exposures or simply age, hair will turn grey.
While as you know by now, we all have some grey hairs throughout our lives, Wientraub wrote that the ratio of grey to colour tends to tip when you’re in your 40s or 50s.
“The rate of change varies by genetics, gender and ethnicity,” Dr James Kirkland, director of the Robert and Arlene Kogod Center on Ageing at the Mayo Clinic told the New York Times.
“Blacks tend to go grey later than Caucasians, with Asians falling somewhere in between. Women generally grey later than men. The age you go grey is determined primarily by genetics, so if one or both parents went grey at an early age, you would be more likely to go grey at a younger age as well.”
Kirkland also said smoking could speed up the process and going grey “early” could be a sign of autoimmune, thyroid or even heart disease.
“If you’ve got heart disease and your hair is grey, it’s a sign of worsening heart disease,” he said.
A dermatologist from the Cleveland Clinic in Cleveland, Ohio, who specializes in hair disorders noted that some people held in concentration camps in World War Two who were starved greyed prematurely.
“Everything is determined by the health of the pigment-producing cell,” she told the New York Times, noting that she had never known of anyone going grey as a result of weight loss or exercise.
“Most activities that are damaging to the hair, like rapidly losing more than 20 pounds or getting chemotherapy treatment, will cause hair loss rather than a change of colour,” she said.
Sadly, there is no medication currently approved that will restore your hair colour and it seems the jury is still out over whether or not stress causes your hair to go grey.
And while former US-President Barack Obama’s hair went from black to silver during his time in office, Obama also aged 47 to 55 during that time, which is when most people start going grey anyway.
Dr Kirkland said studies that have looked into whether or not stress can affect your hair colour have been inconclusive but the consensus had been that stress probably does cause you to go grey.
“But that’s a gut feeling rather than convincing evidence,” he said.
This article originally appeared on Starts at 60.