What is gray hair?

Causes and Symptoms

Hair color is produced by tiny pigment cells in hair follicles called melanocytes. Each melanocyte has long, arm-like extensions that carry the pigment granules known as melanin to the hair cells. In the course of a lifetime, the production of pigment-forming enzymes drops, and the activity of the melanocytes in each follicle begins to wane, resulting in gray hair. Each individual’s melanocyte clock is different, but in Caucasians the reduction of melanocyte activity usually occurs earlier than in other ethnic groups. On the average, graying starts at age thirty-four in Caucasians, in the late thirties in Asians, and at age forty-four in African Americans.

Pigment loss starts at the root, with some strands of hair gradually fading in color, while others may grow in gray or white. Initial graying can be accelerated by hyperthyroidism, anemia, autoimmune disease, severe stress, or vitamin B12 deficiency. Disorders of skin pigmentation, such as vitiligo, can also result in the loss of hair pigmentation.

Once gray hair begins to appear, the rate at which it progresses over the rest of the head depends entirely upon each individual. It does not appear to be a function of the original hair color or texture, ethnic background, or the condition of the scalp. By age fifty, 50 percent of Caucasians are significantly gray. As hair loses its pigment, it often gets drier, resulting in coarser, wirier hair.

Treatment and Therapy

For some individuals, gray hair is a symbol of maturity, while for others it is an embarrassing sign associated with the aging process. In most cases, graying can be readily masked if so desired. Effective chemical and vegetable rinses and dyes are available.

Bibliography

Dugdale, David C., III. "Aging Changes in Hair and Nails." MedlinePlus, November 5, 2012.

Feinberg, Herbert S. All About Hair. New York: Simon & Schuster, 2009.

Greenwood-Robinson, Maggie. Hair Savers for Women: A Complete Guide to Preventing and Treating Hair Loss. New York: Crown, 2000.

InteliHealth. "The Science of Gray Hair." InteliHealth, February 21, 2011.

Jewell, Diana Lewis. Going Gray, Looking Great! The Modern Woman’s Guide to Unfading Glory. New York: Fireside, 2004.

Levine, Norman, ed. Pigmentation and Pigmentary Disorders. Boca Raton, Fla.: CRC Press, 1993.

Schneider, Edward L., and John W. Rowe. Handbook of the Biology of Aging. 7th ed. San Diego, Calif.: Academic Press, 2011.

Scott, Susan Craig, and Karen W. Bressler. The Hair Bible. New York: Simon & Schuster, 2003.