And here's a hint: It has nothing to do with your age.
Shared by Gizmodo, published Thursday in PLOS Biology,"Hair pigmentation over the course of a lifetime depends on melanocyte stem cells that reside in the hair follicle. As old hairs fall out and new hairs grow in, melanocyte stem cells serve as a reservoir for the melanocytes that produce the pigment that gives hair its visible color. The loss of these stem cells leads to the growth of nonpigmented, or gray, hairs."
Melanin is what causes the colors in our eyes, hair, and skin, so when the study was conducted, the team focused in on melanogenesis associated transcription factor (MITF) gene. That gene is said to help produce the Melanin.
Men's Health explains further:
"First, the researchers looked at mice that were bred to go grey early, and found that these guys created a lot of the MITF gene. Harris theorized that more MITF decreased the number of melanocyte cells — therefore creating less melanin. Less melanin means more grey hair.
They also engineered mice to make less of the MITF gene, thinking it would slow the greying process — but they were surprised to find the mice went grey just as quickly."
When they found that interferons were higher in mice that had lower amounts of MITF gene, it was flipped when the interferons were lower - the MITF gene was high. When looking at those differences being the only differences, they concluded that having less of the MITF gene slowed the process, while having a higher count of MITF lead to the idea that men (and women) can grow gray earlier if they possess this combination.
There's no real way to know whether you possess this gene or not - but they're working to find out what exactly is causing it and how we can easily identify it.