Gray hair is one of the most familiar signs of aging. It usually starts in late 30s and graduately increase the percentage on your scalp over the next few years. The loss of hair color is due to a gradual fall in melanin production in the hair bulb. If you look at the hairs on a graying head you find a full range of color, from the normal shade through to white along each hair, and also from one hair to another. Usually people notice their first gray hairs near their temples. Then the grayness spreads to the crown, and later to the back of the head.  

Our hair is made up of two parts: a shaft - the colored part we see growing out of our heads and a root - the bottom part, which keeps the hair anchored under the scalp

The root of every strand of hair is surrounded by hair follicle. Each hair follicle contains a certain number of pigment cells. These pigment cells continuously produce a chemical called melanin that gives the growing shaft of hair its color of brown, blonde, red, and anything in between.

Melanin is the same stuff that makes our skin's color fair or darker.  The dark or light color of someone's hair depends on how much melanin each hair contains. 

There are several reasons for gray hair and these vary from one person to another pending on one's age.  The most common reason is heredity, the other big reason for graying hair is the environment, a recent study indicates that smokers are 4 times more likely to become prematurely gray (or bald). Among younger people, vitamin B-12 deficiency, thyroid imbalance, anemia or viruses can also lead to gray hair.   

As we get older, the pigment cells in our hair follicles gradually die. 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 pigment cells will be around to produce melanin. Eventually, the hair will look completely gray. By combining traditional oriental herbal medicine theory and current scientific breakthrough, Reminex research team discovered by reviving dormant or sometimes nearly dead pigment cells, they are able to prolong the natural hair color stage for older people and prevent premature gray hair or white hair in younger people.