There are three “parent” estrogen compounds - estradiol, estrone, and estriol.
They are “processed”, meaning they are then metabolized, in the liver into a set of the next generation, or “kid” estrogens, called catechol estrogens. These catechol estrogens have their own actions. The main catechol estrogens are the 2 series, the 4 series, and the 16 serie…