Marie Antoinette and Sir Thomas More were both reported to have had their hair turn gray on the nights before their executions. However, hair is dead skin, so it can’t possibly change color. Grey hair means that you have a mixture of white and pigmented hairs. The only way that hair could change color overnight would be to have most of your darker hairs fall out suddenly, leaving only the white hairs. Dermatologists have speculated for many years that Marie Antoinette and Sir Thomas More may both have suffered from a medical condition called alopecia areata in which large amounts of one type of hair can suddenly fall out, and they call it Marie Antoinette syndrome (JAMA Dermatology, June 11, 2009). Scientists at Harvard have published a new study showing how stress can cause hair to turn white, but the process they have explained occurs over weeks or months, not overnight (Nature, January 22, 2020).
Marie Antoinette was born in 1755. In 1770, at age 14, she left her homeland in Austria and traveled to the French palace of Versailles to be married to the future king of France. Nineteen years later, in 1789, the French Revolution erupted and a mob of Parisian women marched on Versailles, shouting for the 34-year old queen’s blood. Many of the members of the mob were actually men in dresses, who thought that the royal troops would be less likely to fire upon women. The mob arrested the king and queen and their children and imprisoned them in the Tuileries palace in Paris. Marie Antoinette was convicted of treason and sentenced to be executed. On October 16, 1793, her hair was reported to have turned white just before she was taken to the guillotine. However, the diary of one of her attendants recorded that her hair change had actually occurred two years earlier.
Hair gets its color from cells containing a pigment called melanin, which is formed only in the hair follicles underneath the skin, so all the hair that you can see is already dead. Hair grows slowly from deep in your skin, with the deep-growing hair pushing the dead visible ends forward outside the skin. The only way that you can develop gray hair is for the living cells underneath your skin to stop making melanin, and this happens slowly with aging. So, as you age, some hairs will be their normal color, while others, the ones with smaller amounts of melanin, will be lighter and the ones without melanin will be completely white. Once the dead hair is visible outside of the skin, its color cannot change.
How Stress Can Cause Hair to Grow In White
Many earlier papers have shown that stress is associated with accelerated hair greying (Arch Dermatol, 2009;145:656), but the mechanism was not known. In a new study, Harvard scientists placed mice in conditions to mimic human stress (Nature, January 22, 2020) and showed that this caused their involuntary sympathetic nerves that are connected to hair follicles to release huge amounts of the hormone, noradrenalin. Noradrenalin causes nerves in the follicles to produce large amounts of melanocyte stem cells that make all the melanin (pigment) in hair. The pigment-producing cells soon exhaust themselves and die so that they can never again produce melanin, so as new hairs grow they are light-colored or white. However, this change would take several weeks or months for the new color to become visible.
Alopecia Areata Could Cause Overnight Changes in Hair Color
Alopecia areata is a medical condition that can cause hair to fall out overnight. On one day, a person may have a full head of hair and on the next, he or she may have only half as many hairs as he had the previous day. If you are about forty years of age, as Marie Antoinette was, you probably have a large amount of white hair already, but you may not know it because most of your hair would still be dark. The dark hair would be far more visible than the white hair and you could appear to have a full head of dark hair. A person who loses hair suddenly because of diffuse alopecia areata loses almost exclusively dark hair, but not the white hair, because the disease causes mostly the dark hairs to fall out. Therefore you have lost most of your dark hair and only the lighter or white hair remains. Then your hair would appear to have turned white overnight. Extreme fear can cause some of your hair to fall out and this may have been what caused the condition in Marie Antoinette and Sir Thomas More.
Hair on your head can never change color. The hair that you see is dead hair above the skin. Hair gets its pigment when it is still deep in its hair follicle.
With aging, hair follicles have fewer melanocyte stem cells so they lose their ability to make melanin, which colors hair as it grows. New hairs grow in lighter, and when all of the melanocyte stem cells are gone, the hair grows in white. The study from Harvard tells us that it may be possible in the future to delay grey hair by making a drug that blocks noradrenalin. Until then, the authors suggest that you may be able to prevent premature grey hair by avoiding stressful situations that may cause your body to produce large amounts of noradrenalin.