David said: The research on plant SERM’s is actually not as clear as one might think. They do not necessarily “fill” estrogen receptor sites, they act as competitive partial agonists . Different plant SERM’s seem to do somewhat different things such as the effects of lignan’s or isoflavones. As for Shatavari it works via the HPA axis, and as such seems to balance the pituitary (possibly FSH and LH), as well as other endocrine activity (this can include the ovaries, etc).