Observe the colour of hair of people around you. Some have black hair, some brown. Our grandparents have gray hair. Why does hair turn gray ?
Hair originates from below the skin or scalp from a type of tissue called the hair follicle. At the follicle, the hair is anchored to the skin. The follicle also contains some pigment cells, which produce a substance called melanin. Melanin, the same pigment that gives colour to our skin and eyes, gives colour to our hair too!
The dark or light colour of someone's hair depends on how much melanin each hair contains.
Pigment-producing cells add colour to our hair as it grows. Darker hair has more pigment than lighter hair.
As we grow older, the pigment-producing cells slowly die off. This is when graying starts. When there are fewer pigment cells in a hair follicle, that strand of hair will no longer contain as much melanin and will become a more transparent color - like gray, silver, or white - as it grows. As people continue to get older, fewer and fewer of these pigment cells will produce melanin, and the hair will eventually look completely gray.
People can get gray hair at any age. Some people go gray at a young age - as early as when they are in high school or college - whereas others may be in their 30s or 40s before they see that first gray hair.
There are many reasons why hair grays at an early age. Poor nutrition, such as shortage of vitamin B, thyroid problems, anemia, and even smoking can all contribute to graying hair. Some diseases can also make people's hair turn gray while they are young.