VITEX Angus pills

So I have a pretty regular period, it ranges between 23 to 27 days. I've been TTC for about 3 years did some check ups even had an HSG done which showed no blocked tubes. But for everything I can't get pregnant I feel like I'm not doing something right. Basically I'd like to know how you ladies feel about using vitex when I don't have PCOS neither do I have irregular periods. I do feel as though my luteal phase is pretty short is about 12 sometimes 13.