Why Does Our Hair Turn White As We Get Older?

Hair naturally loses the capability to produce pigment, or color, with age. Genetics and health determine when you will start seeing white hair and the pattern of change. For some, white hair starts appearing at a young age. For others, the transition occurs in old age. The transition can be smooth and gradual or quick and startling, depending on genetics. Regardless of when it occurs, the process of going white is the same for everyone, and no one is immune.

Anatomy

Before you can understand the changes that cause hair to turn white, you must first understand hair anatomy. Two to three layers of specialized cells make up each hair strand. Although the two outer layers are present in every strand of hair, the inner layer, or medulla, is only present in coarse hair. The extreme outer layer, the cuticle, protects the hair's vital structures housed in the cortex or middle layer. It is here, the cortex, where melanin can be found. Without melanin, hair would be colorless or white since the remaining cells and structures are transparent.
The bulb or root of each hair strand is connected to a nutrient and blood-rich structure located deep in the hair follicle called the dermal papilla. The hair-producing cells and structures located in the root bulb get the nutrients needed to grow hair and produce melanin through the dermal papilla.

Pigmentation

Pigmentation occurs when pigment cells, located in the hair follicle, produce melanin. The color produced depends on the number of melanin cells produced as well as the size of the cells. Darker hair possesses larger, more numerous cells. Lighter hair possesses small cells in fewer numbers. All hair colors, including red, are nothing more than the eye's interpretation of light bouncing off of the melanin cells.

Age

Pigment cells, melanocytes, stop producing melanin with age. According to Aetna InteliHealth, melanocytes gradually stop producing pigment with age, causing hair to become gray and then white after production stops completely. Over time, even the cells themselves disappear.

Heredity

Heredity determines when the cells will stop producing pigment. Some people begin noticing white hair in their 20s. Others are 60 or 70 when they start turning gray. This fact has led dermatologists and geneticists to believe that age is not a good indicator of when you will turn gray.

Considerations

Hair does not turn gray overnight. It changes to gray at the root, and it takes time to grow out. It takes approximately 10 months for a white hair to grow to a length of 5 inches. Sometimes, aging melanocytes produce short bursts of color, resulting in a banded or candy-striped hair.