What Makes Your Hair Gray?

Gray hair occurs naturally as you age. Your hair may start to turn gray in your teens or you may not find any gray hairs until you are near retirement age. Genetics and other factors help determine when your hair starts to gray.

Hair Structure

• Your hair is made up of a protein called keratin. The cells in your hair are very similar to the cells in your skin and nails. Each hair has a hair root that is located below the skin. The hair shaft is the part of your hair that you see.

  The hair root is made up of the bulb that receives blood and nutrients from the dermal papilla. It sits in the follicle which is located in the dermis, or inner layer of skin. The arrector pili are small muscles that cause your hair to stand up. These muscles make you have "goose bumps". Sebaceous glands, which produce oil or sebum, are connected to the hair follicle and help to keep your hair and scalp lubricated.

  Your hair shaft is made up of two or three main parts. The cuticle is the outer layer and consists of scale-like cells that overlap. When the cuticle layer is healthy and undamaged, your hair is shiny and strong. The cortex contains melanin which gives your hair its color. It is located in the middle of the hair shaft. The cortex contains fibrous protein cells that give your hair its elasticity. It is in the cortex that hair color and perming solutions have their effect. The innermost layer of your hair is called the medulla. It is composed of round protein cells. Not everyone has this layer. Natural blondes and people with very thin hair usually do not have this layer.

Hair Growth

• Your hair grows approximately 1/2 inch per month. Women's hair grows faster then men's. Your hair grows at its fastest rate between the ages of 15 and 30. Growth slows down considerabely after the age of 50.

Hair Color

• Melanin within your hair's cortex contains the pigment that determines your hair's color. Naturally occurring melanin called eumalanin is responsible for brown and black hair color. The natural hair colors of red and ginger to blonde tones are caused by the melanin called pheomelanin.

Gray Hair

• Canities is the technical term for gray hair. Gray hair is caused by a loss of the melanin in the hair's cortex. This loss of melanin occurs naturally as you age. It can also be caused by illness, anxiety or worry. Congenital canities is a condition that occurs at or soon after birth. It is commonly seen in albinos who are born with no pigment in their hair, skin and eyes.

Types of Gray Hair

• Except for the lack of melanin, gray hair is usually has the same structure of pigmented hair. Ringed gray hair has the appearance of alternating rings of gray with natural pigment on the hair shaft. Resistant gray hair has a very tight cuticle structure and can be a very hard to color. The cuticle cells are tightly closed and do not allow hair color molecules to enter easily. This can result in an uneven look after you have your hair colored. Resistant hair can be softened before hair color is applied by the use of perm solution. The perm solution helps to open up the cuticle layer to let the hair color molecules enter and thereby changing the hair's color.