Jan 22, 2013

What Causes Gray Hair

A few of these gray things have begun to sprout and it made me wonder why. A person’s hair color is the result of pigments known as melanin produced by a specialized group of cells known as melanocytes. Melanocytes are found throughout our body and the melanin they produce is what gives our skin, hair, and eyes their color. Scientists can determine what color your eyes and hair are from DNA.

The melanocytes responsible for hair color are found in the bulbs of your hair follicles.
There are two main types of melanin. Eumelanin produces dark browns and blacks, and pheomelanin produces reddish/yellow. How these cells blend together determines what color hair will be. It is not fully known what makes the melanocytes blend together in the ways they do, but it appears to be genetic.

Once melanin is produced, their granules are transferred to adjacent keratinocytes, also found in the bulbs of your hair follicles. Keratinocytes are what produce keratine, the dead protein cells that make up our visible hair. Gray hair is the result of less melanin within the keratin. The less melanin, the more gray your hair will be and white hair has no melanin.

As we age our melanocytes decrease in number. The result is less and less melanin, until none are present, so hair slowly turns gray, and then white.

In 2009, scientists in Europe found that hair follicles produce small amounts of hydrogen peroxide. Normally this small amount of hydrogen peroxide is broken down by an enzyme called catalase. As we age, catalase production is reduced and there is a build up of hydrogen peroxide, which blocks melanin production by melanocytes.

There are several other things that can cause our hair to turn gray, including: genetic defects; abnormal hormone production, such as stress; abnormal body distribution of melanin; and climate factors, such as pollutants, toxins, and chemical exposure. The time and speed at which you will gray varies greatly.

As an aside, in Britain, Canada, Australia, Ireland, New Zealand, and South Africa, the spelling is commonly grey. In the United States, the preferred spelling is gray, but grey is accepted.