Once you reach the age of 30, you have a 10 percent to 20 percent chance of graying hair with each passing decade.1 It's a fact of life that, eventually, virtually everyone will go gray. Your hair color comes from pigment called melanin. Each hair may contain dark melanin (eumelanin) and light melanin (pheomelanin), which blend together to form the many shades of hair color among humans. When you're young, special pigment stem cells called melanocytes inject pigment into keratin-containing cells. This keratin, a protein, makes up your hair and is responsible for giving it its color. As you age, melanin is reduced, which is why your hair turns gray and, ultimately, white (this means there's no melanin left).2