Hi Reba,
Yes, you can take them if you are not pregnant, but not sure for how long? I took them for a couple of months before I became pregnant (dr. recommended it). I am pregnant now, and take a prescription chewable ones(the whole ones made me sick). I did see that you can get regular ones at Sam's Club.
I don't know if they make your hair grow faster, but I do know that when you are pregnant, your hair does not fall out (it is not in that phase-there's the growth phase, the resting phase and the shedding phase). That is probably why when women get pregnant, their hair is much fuller (maybe the vitamins help with growth?). Hope this helps!
-Jen