- Each hair root contains a cell called a melanocyte, which produces the melanin that gives hair its natural color. Melanocytes function for a set amount of time. Once they die, the hair without melanin grows out in a transparent shade of gray, silver or white. Gray hair is typically associated with growing older. However, genetic makeup largely determines when an individual gets gray hair, and how much gray he gets.
- David Bank, M.D., director of the Center for Dermatology, Cosmetic, and Laser Surgery in Mt. Kisco, New York, calls graying a natural process. However, if you have more than 50 percent gray hair by age 40, you're considered to be "prematurely gray." Because hair on the head grows faster than hair on other parts of the body, premature gray shows up first on the head. Genetics causes most cases of prematurely gray hair---if your family has many people with premature graying, you have a much greater chance of going prematurely gray yourself. However, prematurely gray hair doesn't mean that your lifespan will be any shorter.
- Certain underlying health conditions can also cause gray hair. These include thyroid disorders (hyperthyroidism), vitiligo and pernicious anemia, which is a result of vitamin B-12 deficiency. Gray hair may also be linked to decreased bone mineral density in women past the age of menopause. Contrary to old wives' tales, hair cannot turn white overnight due to stress or anxiety. However, an autoimmune disease called alopecia areata causes all dark hairs to fall out, leaving only the white hairs.
- No medications can reverse gray hair, although several "snake oil" treatments found online purport to reverse graying. Chinese herbs such as Fo-Ti and supplements containing vitamin B and folic acid have only anecdotal support, at best.
- The only way to "reverse" gray hair is to dye it. Permanent hair color works best, but even this can be a challenge. Colorist Henry Amador, formerly of The Elite Group, notes that hair without pigment is tough and coarse. Therefore, many hair dyes don't provide long-lasting results. Amador recommends pre-treating gray hair with a 20 percent peroxide solution to soften gray. Leave the solution on for 5 to 10 minutes then wash it out before you apply hair dye.
