Are grey hair strands mostly inherited or the result of stress?

At what age can one best tell which cause is the most likely contributor?

I, though not often, have found silver hairs on the right side of my head. I do go through a fair amount of stress in my life, but I am also part Finnish of Swedish descent therefrom. My hair is naturally dark brown in most lighting; couldn't tell you which specific brown.

Are grey hair strands mostly inherited or the result of stress?

Grey hair is a genetically inherited trait, and is not caused by stress. Something else however that can cause grey hair is certain medications.

Are grey hair strands mostly inherited or the result of stress?

Inheritance/genes. You will not develop gray hair simply from stress. Of course, the more stress you have will not be beneficial to a healthy lifestyle. Stress causes your body to "speed" up, therefore making the aging process happen faster. So I guess stress could contribute to gray hair IF it is in your genetic code (DNA). Hope that helps.