Buzz
If you were once the lightest blonde in your class and found yourself sporting darker hair by high school, you're not alone. As we age, many people experience their hair darkening.
According to IFLScience, this change occurs due to variations in melanin production—the natural pigments that give color to hair, eyes, and skin. Two key types of melanin are: Eumelanin, which determines hair darkness, and pheomelanin, which influences warmth. Essentially, those with black hair have the most eumelanin, while red-haired individuals produce more pheomelanin. The melanocytes, which are cells found at the base of hair follicles, create these pigments, and they follow the instructions provided by your genes.
However, your genes don't regulate melanin production consistently throughout your life—hormones can turn certain genes on or off. For instance, during puberty, previously dormant genes might be triggered, resulting in the production of significantly more eumelanin, leading to darker hair.
Over time, however, our cells lose the ability to regenerate as efficiently as they did in youth, which means melanocytes produce less pigment. As melanin levels drop, new hair tends to grow in gray or even white. The exact timing of this process is largely influenced by your genetic makeup—if your family members maintain dark hair into their sixties, you're likely to follow suit.
Can Stress Lead to Gray Hair?
While significant stress might accelerate the graying process, it's not necessarily because your melanocytes stop making melanin. Stress—whether from physical or emotional trauma, severe illness, drastic diet changes, weight fluctuations, or hormonal shifts—can trigger a condition called telogen effluvium, causing your hair to fall out up to three times faster than normal. For those in middle age, the hair that replaces the lost strands could be gray, giving the impression that stress directly caused the graying.
In contrast, a 2020 study found that stress caused gray fur in mice for a different reason. When the mice were stressed—via exposure to a form of capsaicin, which is what makes chili peppers spicy—their sympathetic nerve cells released noradrenaline. This, in turn, rapidly activated melanocytes and caused them to retreat from their hair follicles. Without these melanocytes, the mice's new fur grew gray. More research is needed to determine if humans respond in the same way.
