When my period stopped my mom put me on a regimen of black cohosh. I think it might have helped a little, because I got my period back for a short time while still underweight, and when I stopped taking it, my period became irregular and then went away again until I got up to 120 pounds. I'm back down to 110 again, my "natural" weight, and haven't lost my period thus far (though it's only been back since January). I take black cohosh now to try to regulate my period, to no avail, so I'm starting the Pill this month.
I've also heard about chaste tree berry, but I haven't really seen that in any stores I go to. Of course, I wasn't looking too hard because I don't miss my period when it's gone.
A quick search provided this list of herbs and spices used in an Ayurveda menstrual treatment called Angelica Rasayana #7:
Dong Quai, Angelica, Shatavari, Mugwort, Gotu Kola, Sage, Cinnamon, Parsley, Kelp, Valerian, Rosemary, Celery, Penneyroyal, Shilajit, Amalak, Rose, Chamomile, Saffron, Turmeric, Ginger, Asafoetida, Myrrh
Maybe combining some of these might help?
Also, I found this
. Hope that helps!