Gray hair is a typical sign of getting older. Or maybe not? In fact, there are many young people whose first gray hairs are appearing. Researchers have found that stress is a major cause of gray hair. A stressful lifestyle can affect certain stem cells in the hair follicle. These are directly related to the production of color pigments in the hair. The result: The hair that grows back is white. A lack of melanin is also responsible for the development of gray or white hair. You read that right: When your hair turns gray, it turns white when you look closely. Over time, the cells in our hair roots lose their ability to produce the pigments that give hair its color. This is why colorless or white hair grows back. Because this process does not occur at the same time in all hair cells, white hairs mix with those that still contain color particles. As a result, the “gray hair effect” occurs.