AC (aka Vitex) takes around 3 months to build up enough in your system to be effective. So, if you don't wait long enough it won't do anything. It is a slow working supplement, which is why it doesn't have many (if any) side effects. I have been taking it for 2 months, my cycles before were ranging from 28-36 days, which isn't too bad but they were getting longer and longer. This last cycle I o'd on CD16 and had a 12 day LP= 28 day cycle. I mainly started taking it because the doc told me BC was the only way to get rid of my ovarian cysts. Well, I haven't had any cysts or cyst pain for the last 5 weeks. I can't say for sure it's the vitex, but I think it is as that is the only thing I changed.