PaPE-1 is a "Pathway Preferential Estrogen" that activates the extranuclear signaling pathway without activating the nuclear signaling pathway. PaPE-1 bound 50,000-fold less well to ERα and Erβ estrogen receptors. PaPE-1 activated extranuclear-initiated ER-regulated genes, but showed essentially no activation of nuclear-initiated estrogen receptor (ER) gene targets such as the progesterone receptor. Unlike estradiol (E2), PaPE-1 did not stimulate proliferation of MCF-7 breast cancer cells. Like estradiol, PaPE-1 strongly activated MAPK and mTOR pathway. Instead, it showed preferential estrogen-like activity in non-reproductive (metabolic and vascular) tissues, reducing body weight gain and fat accumulation in ovariectomized mice and accelerating repair of endothelial damage in the vascualture.