Can white hairs be replaced by black hair? If they can, will no white hair will grow afterwards?

Thank you for posting your question on realself.com sanskar bansal. Replacing your white hair with black ones might seem like a good idea, but it would not last as the black hairs may also turn white as well. There are a number of ways to safely color your hair.

You cannot "replace" a grey hair with a black hair.  Even if you could, the black hair may later turn grey.

This is not an uncommon question.  If your hair is turning white, even if only dark follicles are harvested and transplanted they will eventually turn white also.