I don't know, sorry, but I'll ask before anyone else does: why are you asking? Was I polite enough there, Plazma?
Fear is said to turn your hair white. Maries Antoinette's hair is said to have blanched on the eve of her execution. A chemical that made you very fearful might work.
So basically to turn you hair white, go to the cemetery and sleep there on a tomb...listen to every sound around you. perhaps the hair will turn white next day.
That just has to be a myth. At the most charitable, it would qualify as "an extraordinary assertion requiring extraordinary substantiation." Hair is not living tissue, except for the root. How could it be alive? It has no blood supply, no nerves, etc. No biological processes can take place in strands of hair. Therefore nothing that happens to us physically or mentally can be expressed as a change in our hair. Unless it happens to the hair directly of course, such as drying out, split ends or treatment with chemicals.
If you deactivated the telomerase in your scalp, you'd get gray hair. Probably end up with no hair, though.
Not bad, because it's not your fault. You cannot help being rufous. Are you sure you mean ginger? I'm not talking about red hair, I'm talking orange.
Since I've quit eating meat my hair colour from dark brown gradually has become a lot lighter brown. Maybe there are other factors as well.
