Going gray, by itself, does not mean you have a medical problem, except in rare cases.
Contrary to popular belief, stress has not been shown to cause gray hair. Scientists don’t know exactly why some people go gray early, but genes play a large role.
Also, a vitamin B-12 deficiency or problems with your pituitary or thyroid gland can cause premature graying
Gray hair is, along with premature balding, one of the greatest fears of image conscious men and women everywhere,
Anemia may also be a contributing factor, but whatever the cause, the results can be distressing and lead to a loss of self confidence