Why do we get white hair?

Melanin:

Our hair is basically made up of keratin, a colorless protein. Hence, before our hair comes out of the skin, it's basically white. Our hair grows from the hair follicles. Hair follicles contain melanocytes which produce melanin. That melanin is injected into the keratin cells during the growth of the hair. This melanin gives color to our hair. Now, the color of our hair is depending on the type of the melanin injected into our hair. Eumelanin makes our hair black or brown while pheomelanin makes our hair red or blond. However as we grow, the melanocytes decrease the production of melanin. Thus, less melanin is injected into our hair causing them to eventually turn white.