Vitex Agnus Castus or ‘Chaste tree’, does not supply a hormonal substance but acts directly on the Pituitary gland to inhibit the secretion of FSH (follicle stimulating hormone) and promote the secretion of LH (lutinizing hormone).
FSH causes the granulosa and theca cells in ovarian cells to grow and secrete a follicular fluid that contains a high amount of estrogen. Therefore inhibition of FSH secretion should reduce elevated estrogen levels.
LH is essential for the creation of the corpus luteum in the ovaries.
The corpus luteum then produces progesterone. When enough progesterone is produced, it slows the pituitary influence.
If LH is limited because of pituitary imbalance, oestrogen continues to be the dominant female hormone during the second phase of the cycle, known as the ‘luteal phase defect’, and leads to symptoms such as cramping, breast tenderness and mood swings, (the typical PMS symptoms).
Therefore what appears to be an oestrogen excess can actually be a deficiency of progesterone.
Vitex Agnus Castus also inhibits the secretion of prolactin. As prolactin suppresses the corpus luteum, this leads to a reduction in progesterone production. Therefore if prolactin is reduced it follows that the corpus luteum would increase its production of progesterone.
Vitex Agnus Castus, then will have a balancing effect on hormones with particular effect on increasing progesterone. It can decrease PMT symptoms, help regulate an irregular cycle and other menstrual irregularities and can help in cases of infertility due to luteal phase defect.