Why does hair turn gray?

                        How Does Hair Turn Gray Over Time?

In human physiology, the compound responsible for skin, hair and eye color is called melanin. Melanin exists in different types and concentrations from one person to the next, resulting in a host of colors that can change over time.

When it comes to hair, melanin is produced by pigment cells that rest at the base of each hair follicle. The specific type of melanin produced determines the color, while the concentration of the melanin controls the depth of the color.

The Appearance of Grey Hairs

The pigment cells that give color to each hair follicle cannot live forever, and there are only so many of them per follicle. When they start to die, the pigment in each follicle begins to diminish. This is a gradual process that can take several years, but given enough time, the follicles go from fading to grey or silver and eventually to white.

All melanin-producing hair cells die eventually, causing greyness, but exactly when the pigment cells die is left up to a variety of factors.

Factors Related to Greying Hair

The most apparent and significant cause of greying is aging. Like all tissue cells, the pigment hair cells age and die, but unlike many other types of cells, they are never replaced.

Another major factor is genetics. A person's genetic makeup determines the age at which the greying process begins, and one can generally estimate the point at which their hair will begin going grey by investigating when their ancestors began going grey.

While medical conditions typically do not cause greyness on the same scale as is caused by aging, some conditions can cause a person's hair to go grey earlier or faster than normal. These conditions include iron deficiency, vitamin B deficiency, thyroid disorders and malnutrition. Although rare, premature greyness can be caused by some radiation treatments like chemotherapy. However, total hair loss is a more common result of these treatments.

why does hair turn gray?