It is true that stress is one of the factors of premature greying of hair. Normally, it is occurred by two factors. Firstly, it is a genetic factor. If someone in your family have white hair before age, you are also prone to have early white hair. Greying of hair before age of 30 is considered as premature greying.
Another factor usually found nowadays is stress. The study found that our hair follicle, generally, has stem cells producing hair pigments. However, as these stem cells have limited amount, when we grow older, it is gradually reducing until pigments are unable to be produced. Therefore, our hair turns white.
In stress condition, our body will respond by stimulating sympathetic nervous system which rapidly reduces the stem cells and leads to premature graying. It is found that this condition cannot be cured. Therefore, decreased stem cells are unable to be reproduced. That’s why greying of hair before age is permanent. Furthermore, stress level directly affects to stem cell reduction rate. You may have ever heard that some people facing the unexpected event or having suddenly stress, shock, or fear can have white hair in very short duration.