Why does hair turn gray?

You can try to run from these cranial oppressors, but they'll always catch up; we're talking, of course, about gray hairs. While they don't always have the best reputation, gray hairs are a natural part of life. But why? Why do our luscious locks lose their color as we age? The pigments in our hair are produced by what's known as melanocyte stem cells. These specialized cells are passed to hair progenitor cells at the base of the hair follicle and changed into parts of the growing hair, incorporating our unique hair color. Over time, these cells become damaged and the melanocytes lost, causing the hair that grows afterwards to be either gray or white. So what exactly causes pigmentation? Human beings have two separate types of pigment: eumelanin, which creates black and brown colors, and pheomelanin, which creates orange and yellow. Hair progenitor cells reportedly release a protein known as 'stem cell factor,' which is necessary for pigment to be produced by melanocytes. When tested on mice, researchers found that if the protein was missing, no hair color was produced. Additionally, researchers have reported that when the DNA of melanocyte stem cells in the hair follicles of mice were damaged, permanent cell damage occurred. This meant that the stem cells were unable to reproduce, resulting in gray or white hair from the absence of the melanocyte stem cells. Though this process is yet to be fully verified in humans, it appears that damage to melanocyte stem cells and the subsequent loss of pigmentation occurs in a similar way to humans as it does mice. Furthermore, going gray is not exclusive to age. With research from 2016 stating "individuals with a certain variant of the gene interferon regulatory factor 4 are prone to earlier graying," graying can occur at any time in a person's life, even as early as their twenties.