How do i get rid of white hairs that are growing on head rapidly. i'm 25 years old male. why i am getting white hair in this early age? pls. help.

Some things: There are a few reported readily reversible causes like B12 deficiency and thyroid disease that can be readily tested for. There are some other less common causes like pigment diseases(think vitiligo), but again, these are rare. It's more likely that this is genetic. But you can do some things to help avoid worsening things, like avoid smoking and harsh chemical hair products.

Whitening of hair is: related to genetic predisposition. Age of initial graying is largely a matter of genetics. However stressors: nutritional deficiencies, chemotherapy, traumatic head injuries, low vitamin B levels, zinc deficiency, severe illness, surgery & marked emotional stress may impact earlier depigmentation in people who are already predisposed to gray hair. Aging is a significant factor. In general–genetics