Vitex

Backstory: went to an OB appointment for a check up and mentioned to her that we are TTC but I haven't gotten a positive opk even though I've been having semi regular periods. She said that if I go another three months without a positive opk, she's putting me on metformin. I'm trying to avoid that. I've read that a supplement called Vitex helps with irregular cycles and hormones and the like. Has anyone tried it (not necessarily to conceive, I just want to know that nothing crazy happened like you went temporarily blind or your vagina falling out or something)