Hormone Replacement Therapy can basically be divided into two types: First, Phytoestrogens, which are plant compounds that have beneficial, hormone-like effects in the body. Secondly, hormones which are natural or endogenous to the female body.  

Phytoestrogens come in two main classes:

1. Isoflavones (soybean is the major source)
2. Lignans (found mainly in flax seeds, whole grains and some     fruits and vegetables)

The Natural or Endogenous Hormones of the body most commonly talked about are as follows:

1. Estradiol (E2)
2. Estrone (E1)
3. Estriol (E3)
4. Progesterone (P4)
5. Testosterone
6. Dehydroepiandrosterone (DHEA)
7. Pregnenolone

There are a couple of misconceptions which people have about the Natural Hormones. They are considered to be of plant source, but not in the way that most people think.
A basic sterol structured compound is extracted from the plant (mainly soybean) and then semi-synthesized into the exact duplicate of the natural hormones found in the body. People have the notion that since they are "natural," they are found in the plant source as the exact hormone entity, and the idea that there has been some chemical process involved suggests that they are no longer "natural". Remember "natural" to these hormones means exact duplicates of the natural hormonal products found endogenous to the body.

Natural Hormones may not be indicated for everyone. Very careful consideration and evaluation is necessary when one is considering an HRT program.