I have done tons of reading on this product and it's effect on lengthening the luteal phase and also increasing progesterone levels. I suffer from high prolactin levels and as a consequence I have low progesterone levels. Progesterone is VERY important to make a fertilised egg implant otherwise, even though you may have conceived, the egg breaks down and you will experience a period. From what I have read - Vitamin B6 must be taken with care. A dose higher than 200mg per day can cause nerve ending damage and you must ensure that you are getting enough of the other B vitamins. I am presently on a Prenatal and I have decided to supplement with Vitamin B6 and with Agnus Castus capsules. Dosage: It is suggested not to take more than 100mg unless it is given by a doctor. So I have decided to take 100mg per day - this is jumping in on the deep end really - LOL. If I experience any side effects - I will lower it to 75mg. If I do not get pregant soon, I will share my experience of taking this vitamin as I go along. I am three months off the pill and my cycle is at 32 days at present, it does not seem I have a luteal phase. I have "JUST" a 12 day luteal phase at present. But - I want to increase my progesterone level so if I lengthen my LP by 2 days in the process I'd be happy!