I know people who take prenatal vitamins to help with hair and nail growth, but never head of anyone putting them (or birth control) pills in shampoo. Don't really see how that would have any effect on one's hair at all.
Hair grows from beneath your scalp. Nothing you put ON hair helps it grow. The hair you see is no longer growing, it is dead keratin just like your fingernails. People have been taking vitamins to help hair grow, but they swallow the vitamins....they do not put them ON their hair.