Stopping Vitex and earlier O?

[MrsPete]

I've been taking Vitex (agnus castus) for 6 months and finally decided to quit since it didn't seem to be helping. As soon as I stopped taking it my O moved from CD 21 to CD 16.... Haven't taken any more Vitex but my O has been on CD 16 for the past 2 months. I've been using progesterone supplements PO since I stopped the Vitex so I don't know if it lengthened the luteal phase or if it just resulted in an overall shorter cycle. At first I thought the progesterone was causing the earlier ovulation but today I looked at my charts and realized the earlier O started BEFORE I started progesterone. Still don't have a BFP but thought it was interesting.