I haven't tried it before but I have seen people talking about it on JM and they all seemed to like it quite a bit.
I did some quick googling too and of the various options available Fertili-tea seems to be generally considered pretty safe. There is the warning to make sure you don't take it once you are actually pregnant, so I think if I were to try it I would maybe stop taking it by 7DPO, although they say it is safe until you get a positive test.
If you try it you will have to let us know how it goes

you have peaked my interest in it again.