Why do we get white hair?

Because we cannot get blue hair.

No.

Our hair is basically made up of keratin, a colorless protein.

Hence, before our hair comes out of the skin, it is almost white.

How's that possible?

I had black hair during childhood.

Don't worry.

I will explain.

Our hair grows from hair follicles.

A hair follicle contains melanocytes which produce melanin.

Melanin is injected in the keratin cells during the growth of our hair.

This melanin gives color to our hair.

Now, the color of our hair is dependent on the type of melanin injected.

Eumelanin makes our hair black or brown while pheomelanin makes our hair red or blond.

However, as we grow old, the melanocytes decrease the production of melanin.

Thus, less melanin is injected in hair, causing them to eventually turn white.