Estriol, unlike estradiol, increases my libido, makes me more androgenic, impulsive and so forth.
It does this by displacing estradiol from the estrogen receptor and since estriol is a weaker estrogen (by 100x or something), it will in fact block the strong estrogen from doing its job. The end effect is less estrogenic activity and more androgen dominance. It is basically a natural 'RU' for estrogen.
Think about it. Anything that increases your androgenicity, libido, etc. cannot be good for your hair in the long run.
I can't comment about your personal experience with estriol, but many, including myself, have noticed strong libidos with estradiol. I also have great workouts and do not feel suppressed with b-estradiol. At the same time, I've had no improvement in hair with b-estradiol. I confirmed my blood levels of both estradiol and total E and I am very elevated from baseline.
I've followed your theories re: estrogen in another thread and have some issues with your ideas about with form is superior. While I understand the concept you propose about the weaker variant outcompeting estradiol for binding sites, the other variable is affinity for the receptor. I checked on a paper very quickly (
https://academic.oup.com/toxsci/article/54/1/138/1670624) and estradiol IC50 for ER is 0.9 nM, whereas estriol IC50 is 9 nM. Due to the higher affinity for ER of estradiol over estriol, I would speculate that adding a modest dose of estriol would in no way abolish estradiol's ability to bind to the ER receptor. Sure, there may be a little less estradiol binding, but it could be beneficial to have some ER activation of estriol in parallel. I propose that adding a mixture of both estrogens could be ideal.
The other issue you may not have addressed (sorry if I missed it), is that estradiol converts to estrone in the body. Estrone is bad (thanks
@bridgeburn). My blood test shows that I likely have significant levels of estrone since my estradiol is 61 pg/mL and my total E is 334 pg/mL. I believe most of my total E that is not estradiol is estrone because biochemically that's the most obvious path via alcohol oxidation to ketone. The beauty of estriol is that it does not convert to estrone, so you are guaranteed to only have 'good' estrogen on board when applying estriol.
Finally, doesn't b-estradiol also agonize the 'bad' ER receptor (is it ER-
alpha?)
Please do correct anything I've said that is off base. I care little about being right...just want to figure this stuff out.