Chemical structure of the bioidentical hormones is the same as the natural hormone that is produced in human body.  Normally both bioidentical as well as the non-bioidentical types of steroid hormones are chemically manufactured using diosgenin.  It is one of the cholesterol like molecule that is normally found in the plants.  Normally in bioidentical hormone therapies normal characteristics and symptoms of the natural hormones are taken into consideration. There are of course some exceptions as well.  One of them is the Premarin extracted using the urine of mares that are pregnant.  The product also contains the horse estrogen molecules. Some of the molecules have human component while others are peculiar to horses alone. Both however are used for the bioidentical hormone treatments.