Prenatal vitamins are dangerous if you arent pregnant.They are meant for the baby not for hair.Taking them when you are not pregnant could lead to organ damage.
I know because after my pregnancy I continued to take mine for about 3 months. I was tested by my doctor to make sure everything was back on track,and was told my iron counts were so high I could do serious damage if I didnt stop taking them right away.
Biotin is good though,and the scalp massages.
Also,getting plenty of sleep~hair grows fastest while sleeping.