Before her beheading, Queen Marie Antoinette reportedly saw her hair turn white in a single night. The existence of this phenomenon, called since “the Marie-Antoinette syndrome“, is debated among scientists.

The moustache of Henri IV

According to legend, the last queen of France saw her hair turn white the night before her ascent on the scaffold, October 16, 1793. Sainte-Beuve, in his Monday talks, assures us that the transformation has taken place two years earlier, on June 21, 1791, during the arrest of the royal family in Varennes at the end of their attempt to escape from France: “When Mme Campan saw her again after returning from Varennes, the queen took off her bonnet, and told her to see the effect the pain had had on her hair: “In one night it had turned white like a 70-year-old woman’s.” She was 36. ” Even if it bears the name of Marie-Antoinette, this sudden and spectacular metamorphosis is reported in the literature long before. It is said that the future Henry IV saw his mustache turn white overnight. But how is this possible?

A reaction of the body’s immune system

In 2020, a new mechanism that may explain sudden hair bleaching was uncovered and described in the journal Nature. After exposing mice to stressors, researchers found that rodent hair follicles lost pigment-producing melanocytic stem cells, until the mice were left with hairs as white as the pre-run hair. by Marie-Antoinette. The reaction was triggered by norepinephrine, the neurotransmitter of the sympathetic nervous system. Why ? Because hair or white hairs are, in many species, a marker of experience, and therefore of potential leadership. “Male mountain gorillas get gray hairs on their backs after reaching full maturity, and can then, and only then, lead a gorilla troop,” report two neuroscientists Shayla Clark and Christopher Deppman. So how can hair turn white overnight? This syndrome, called “sudden canities“, is today interpreted as an autoimmune reaction: the body’s immune system seems to have a sudden rejection reaction from the pigmentary system of the hair follicles. If this attack occurs on salt and pepper hair, containing both pigmented hair and other already white hair, only the pigmented will be “rejected”, and therefore lost, while the white hair will be spared. “Overnight” bleaching is believed to result from selective rejection of pigmented hair.