As a subject matter expert in the field of biology and human physiology, I can tell you that the idea that fear can cause your hair to turn white is a myth. Hair color is determined by the presence of pigments called melanin, which are produced by cells called melanocytes. The production of melanin decreases with age, which is why hair turns gray or white over time. This process is not influenced by emotions such as fear.

While it's true that stress can have various effects on the body, including hair loss in some cases, there is no scientific evidence to support the notion that being scared can change the color of your hair. Hair color change is a long-term process that involves the gradual depletion of melanocytes, which is not something that happens as an immediate response to a frightening event.

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Once the hair grows out of the head, it can't be influenced by any psychological or physiological processes in the body (including scares or shocks). Even if an illness, injury, or sudden shock could turn hair white, it would be weeks before the effect would be visible because only the root would be affected.read more >>