- The largely accepted theory as to the cause of premature graying is genetics. Other suggested cause include: cigarette smoking, stress, chemical imbalance, lack of vitamin B12, thyroid problems or overuse of Vitamin E or Echinacea.
- According to a report published by the Journal of Investigative Dermatology in 2005, the age at which a person goes gray seems to be determined by heredity. Scientists involved in studying gray-hair causes can only determine that even if stress and/or other factors are proven to play a role, it is genetics that causes these susceptibilities, as some people gray at certain ages and some never gray at all.
- A 1996 study published in the British Medical Journal found a relationship between cigarette smokers and premature graying and hair loss. It is unclear whether the connection is due to premature aging caused by cigarettes, or specific toxins in the smoke that cause hair follicles to cease pigment production.
- Stress has often been named a culprit for gray hair, but no studies have found conclusive evidence that stress leads directly to graying. It is most likely, however, that if there is a relationship between stress and graying, genetics must still play a role to determine whether a person is susceptible to stress-related premature graying.
- A CNN report published in 1999 stated that vitamin E and Echinacea are among certain herbs and supplements known to cause graying. A lack of certain vitamins has also been linked to graying, specifically vitamin B-12. Graying has also been linked to thyroid conditions and pernicious anemia, a condition that makes the body unable to absorb vitamin B-12.
- A gray-hair report, published in February, 2009, in the Journal of the Federation of American Societies for Experimental Biology (FASEB), suggests that catalase, an enzyme found to be low in skin lacking pigment was found to break down hydrogen peroxide. The report linked this enzyme and hydrogen peroxide levels to the same absence of pigment in graying hair, and the scientists hope to be able to use the information to determine why these chemicals are being slowed prematurely.
- Many people link stress and premature aging to grayness, while experts hold that this is not the case, or at least not proven. People who go gray prematurely do not have shorter lives than those who do not, meaning it is most likely not a sign of premature aging. Other misconceptions as to the causes of premature graying involve beliefs that an unhealthy scalp condition can cause premature graying.
