Quote from: KayXo on October 06, 2017, 09:12:29 AM
https://www.ncbi.nlm.nih.gov/pubmed/3297211
"Progesterone may also have an antagonistic activity against estradiol, mediated through a decrease in the replenishment of the estrogen receptor, and also through increased 17 beta-hydroxysteroid dehydrogenase which leads to accelerated metabolism of estradiol to estrone in the target organ."
Confirmed by several other sources and by the fact that progesterone opposes estrogenic effects on the uterus and breast.
Even John R. Lee said progesterone in excess would do this. Idea is to get them balanced.
It's interesting because I was taking a certain amount of estradiol per day orally for many years, then I took that same dose sublingual. My breasts swelled up (along with substantial development) along with improvements to my skin. The swelling and development slowed down after about 2 months to where they were no longer swollen but definitely had more tissue.
Well when I started on progesterone cream (USP Progesterone), with 1/2 the dose of my oral estradiol, I had the same exact thing happen: breasts are swollen and skin improvements. And it feels like my breasts are developing all the same -- I'll let you know in month or two. And now since I am on progesterone I should also get extra development since it'll be working on the lobules. Dr. John R. Lee also said the effects of the swelling are temporary and that they would wear off in about 2 months (interesting because that's how long extra dose of estradiol took to wear off, i presume due to resistance over time) and said it was the influence of estrogen due to sensitization of the receptors -- he said this can happen in women who were severely deficient in progesterone for a while.
So this leads to me to believe if I was progesterone deficient (which I was since I didn't take it before), that the progesterone I rubbed on my skin absorbed immediately and started working, sensitizing estrogen receptors. Making the 50% dose of oral estrogen work as well as 100% dose estradiol sublingual.
I've been reading on hystosysters forum that swelling and pms symptoms can happen if there is an imbalance of either hormone, not just too much progesterone, as I think you are lead to believe.
I haven't ruled out that, for the best development, cycling isn't a better method, since the two hormones would switch back and forth to balance each other out and not desensitize the receptors. I need to look into this more.. just a thought I have.
Btw, I've read in other studies that excess doses of estradiol does in fact down regulate the receptors, makign the cells more resistant. They do this for other hormones like insulin etc.. why not sex hormones as well?