How much faster will vitamins make my hair grow?

I've heard that certain vitamins help hair grow stronger and faster. I'm on multivitamins and am hoping that my hair will grow more quickly.I know that hair, on average, grows about 1cm-1/2inch per month. How much faster might my hair grow by taking multivitamins?If it helps, I take 1 vitamin C supplement and another "complete" multivitamin everyday.

Hair growth rate is genetically determined and no pills will make your hair grow faster however they might improve the overall health of your hair.