They talk to cells through specific receptors that are made for them. For example, bio-identical estradiol (a type of estrogen
) in patch
form, gel or cream (brand names: Estragel, Estradot, Tri-Est, Bi-Est) acts just like the estradiol our ovaries secrete into the bloodstream. However, bioidentical estradiol in pill form (brand names: Estrace, Tri-Est, Bi-Est) has the negative effect of increasing blood clots because it is not natural for estrogen to enter the bloodstream through the stomach.