According to WorldHealth.net our hair turns gray because of the presence of hydrogen peroxide and the absence of sufficient levels of the enzyme catalase in our bodies.

In time, everyone's hair turns gray. In fact, our chances of going gray increase 10 to 20 percent every decade after we turn 30.

 

Now, scientists have discovered why our hair turns gray as we age: it's the result of a chain reaction. Specifically, over the course of a lifetime, human hair follicles slowly produce hydrogen peroxide. When the levels of the enzyme "catalase" begin to drop as we age, that natural bleach cannot be broken down. According to WebMD, knowing why hair turns gray could lead to the development of new "anti-aging strategies."

 

"All of our hair cells make a tiny bit of hydrogen peroxide, but as we get older, this little bit becomes a lot. We bleach our hair pigment from within, and our hair turns gray and then white," explains Dr . Gerald Weissmann, a research professor of medicine at New York University and editor-in-chief of The FASEB Journal. And he adds:  "Our bodies age the same way a photograph age. Hydrogen peroxide does to our hair - and the rest of our body - what sunlight does to photos and furniture that have been left out in the sun."