[AbiDrew85]

Well. There is entirely too little research done on BO to conclusively call ANYTHING about it fact. PM and in fact almost ALL phyto's however, is absolute fact that they bind more strongly to beta receptors. There are ample studies to prove it if you just do a simple google search on the topic. That's part of why they have an anti-cancer activity. They're weaker than estradiol, but not too much, but it's just enough to prevent cancerous activity which seems to be more commonly activated by estrogenic activity on the beta's.

BO is more extrapolation on my end since it's animal source and there has been a lot of research on other animal source estrogens that aren't human. They typically bind more strongly to the alpha's, even compared to human estradiol. And practically ignore the beta's. This is based mainly on studies done on premarin. Which are horse estrogens conjugated from their urine.

Likewise, there are supporting studies which indicate that increased binding of alternative estrogens to beta receptors encourages increased binding of natural estradiol to the alpha's. I'd say that in most women, they shouldn't need to combine. It is more expensive.