There are many studies on bioidentical hormones.
I'm a pioneer in the serum dosage of estradiol and progesterone. I have been doing that since January 2005. I was my own teacher. There was nothing on the subject. It was always said that measuring female hormones was pointless. I went to read the literature, I checked the journals, and there was nothing on it.
There was a lot of small-scale research, though. For example, in cardiology, it was observed that when middle-aged women had a certain dosage in perimenopause, they began to suffer from hypoestrogenism and osteoporosis.
There have been small studies on high blood pressure, depression and so on. There have also been many studies on osteoporosis, particularly about protective factors. With all of that put together, many doctors around the world are now adjusting doses for hormone therapy.
The study I was talking about was a major study published in the United Kingdom that came to more or less the same conclusions as mine.