While many people associate grey hair with the stresses of life, research shows that stress is not typically the direct cause of grey hair.
In reality, hair doesn’t “turn” grey – rather, it begins grey from the moment it grows. The color of each hair strand is determined as it is produced by the hair follicle. Once a strand of hair grows out brown, black, red, or blonde, it will not change unless intentionally colored.
As we age, hair follicles naturally produce less pigment, which causes hair to gradually lose its color and grow in grey. Most people begin to notice this process around the age of 35, and genetics play a significant role in when this transition occurs.
While stress doesn’t change the color of individual strands, it can trigger a condition called telogen effluvium. This disorder speeds up hair shedding, causing hair to fall out about three times faster than usual. However, the hair usually grows back, and the condition doesn’t lead to permanent baldness. In cases of telogen effluvium, especially in middle age, the new hair that grows in may be grey instead of the original color due to the faster regeneration process.
Interestingly, a 2020 study involving mice showed that stress can cause fur to turn grey, but it’s still unclear whether the same mechanism applies to humans and how often it contributes to hair greying.
Grey hair can sometimes be a sign of an underlying health condition, particularly if it occurs at an unusually young age. Conditions like vitamin B12 deficiency, neurofibromatosis (Von Recklinghausen’s disease), tuberous sclerosis, thyroid disease, vitiligo, and alopecia areata have been linked to premature greying.
In the case of alopecia areata, for example, patches of hair loss may occur suddenly, making previously grey or white hairs more visible, potentially leading to an “overnight” appearance of grey hair. As hair regrows, it may continue to be white or grey, but colored hair may eventually return.
The truth about when and how your hair turns grey ultimately lies in your genetic inheritance. While stress may have an indirect effect on the process, the timing and extent of grey hair are mostly determined by the genes passed down by your parents, rather than your current stress levels. Whether you’re a high-profile individual or someone with a more laid-back life, it’s your family history, not stress, that’s most likely to decide when grey hair arrives.
