Wondering if taking Vitex will bring on menstruation...?

I have never had regular periods (3-9 months apart) due to a thyroid issue (although it is regulated now), so I want to try using Vitex to normalize my cycles. I've used Provera before, but I want to try something natural and with better results. I heard it can help, however I can't find much about it other than if you're ttc. First and foremost, I just want to be normal! I have been taking one pill (400mg) in the morning and one at night for 2 days now. So, will Vitex bring on menstruation if my last period was 2 months ago? How long will it take? Do I continue to take it every day? If so, for how long? Any answers on the subject would be helpful! Thanks!