It is said that Marie Antoinette’s hair turned gray overnight just before her beheading in 1791. Although it is unlikely that something like this has happened, since once the hair that has grown out of the follicle hardens and crystallizes it does not change color, but it is true that gray hair can result from stress. In fact, it is not unusual to see the hair graying of many newcomers to positions of great responsibility.
How does stress cause gray hair?
Researchers from Columbia University delved into the relationship between stress and gray hair. To do this, they measured the levels of thousands of proteins found in hair and the changes that occur in each hair.
They explain that in the same way that the rings in the trunk of trees contain information about the past decades of their life, our hair contains information about our biological history. To assess the loss of pigment (gray hair), they analyzed the color of each of those human hair rings.
They found that when gray hair appears, changes occur in 300 proteins. So they found a “culprit”: mitochondria. Mitochondria are the powerhouses of the cell, but they also play other roles. They are actually like little antennae inside the cell that respond to a number of different signals, including stress. In fact, it has been appreciated that gray hair has more proteins linked to mitochondria and energy consumption.
And it is that when the hair is still under the skin, it is subject to the influence of stress hormones and our emotional states in general. Therefore, the biochemical changes that stress produces in our body end up affecting the pigmentation of the hair. Norepinephrine affects stem cells, preventing them from turning into melanocytes that target the hair follicle to color hair.
Stress gray hair can disappear
These researchers not only analyzed the volunteers’ hair, but also compared their daily and weekly stress levels. They not only found that stress causes gray hair, but that when it disappears, the hair can darken again.
However, they also indicate that the natural color cannot always be restored. Hair must reach a threshold before turning gray. In middle age, when hair is close to that threshold due to biological age and other factors, stress will accelerate the appearance of gray hair and it is very difficult to reverse it. However, in younger people who have gray hair, reducing the stress level may allow them to regain their original color.
Rosenberg, A. M. et. Al. (2021) Quantitative mapping of human hair greying and reversal in relation to life stress. eLife; 10I: 10.7554/eLife.67437.