Even today, medical students are taught that the proper treament is estrogen replacement therapy. Estrogen does, in fact inhibit the osteoblast cells that function to resorb bone and as a result can slow the rate of bone loss. But estrogen alone cannot rebuild bone. Progesterone rebuilds bone by stimulating the osteoblast cells that re-mineralize and restore bone mass. Transdermal progesterone does this with virtually no side effects.
Progesterone also acts with estrogen on breast tissue.
Many undesirable side effects can occur with the use of test tube designed progestins or progestenogens prescribed by many doctors. In addition, they are not as effective as natural progesterone which is made by the body or made by plants. More than five thousand plants can produce progesterone. They are well accepted by the human body. Probably the most workable and effective from the standpoint of accuracy of dosage, and ease of usage is liquid progesterone derived from wild yam.