Bio-identical hormones have the same chemical structure as hormones that are made by the human body. The key to natural or bio-identical versus synthetic is the molecular structure of the hormone. In order for a replacement hormone to fully replicate the function of hormones which were originally naturally produced and present in the human body, the chemical structure must exactly match the original.
Researchers have long held that there are significant differences between hormones that are natural to humans (bio-identical) and synthetic (including horse) preparations. Structural differences that exist between synthetic or animal and human hormones can be responsible for side effects that are experienced when non-bio-identical hormones are used for replacement therapy, It is the structure of the hormone, not the source that is key, The term “bio-identical” does not indicate the source of the hormone, but rather indicates that the chemical structure of the replacement hormone is identical to that of the hormone naturally found in the human body. Bio-identical hormones are chemically processed from precursors found in yams, or soy plants, yet they are Identical to the hormones produced by the human body; hence the term “bio-identical plant-derived hormone.” These hormones are able to follow normal metabolic. pathways so that essential active metabolites are formed in response to hormone replacement therapy, Synthetic––”patented,” “conventional,” “artificial,” or “horse”––hormones have been chemically altered, and are not identical in structure or activity to the naturally occurring hormones they are intended to replace.
Side chains are added to a natural substance to create a synthetic product that can be patented by a manufacturer. A patented drug can be profitable to mass-produce, and therefore a drug company can afford to fund research as to the medication’s use and effectiveness. However, bio-identical substances cannot be patented, so scientific studies are less numerous on these natural hormones, as medical research is frequently funded by drug companies.
Today’s women prefer natural hormones. In a survey of a nationally representative sample of 1,009 women aged 40 and older. 83% said they would prefer to use hormones that are similar to their own body’s hormones. Bio-identical hormones include estrone (E1), estradiol (E2), estriol (E3), progesterone, testosterone, dehydroepiandrosterone (DHEA), and pregnenolone.
Benefits of Natural Hormone
 Replacement Therapy
•    Fewer side effects versus synthetic derivatives
•    Protection against heart disease
•    Reduced risk of breast cancer
•    Improved cholesterol and lipid profile