E2 (17β-estradiol) is one of the most potent sex hormones and it is the most potent estrogen: being 10-times as potent as E1 (estrone) and 80-times as potent as E3 (estroil). It is also the form of estrogen used by many during their male-to-female transition.

But how does PM's estrogen-like potency measure up to the estrogenic potency of E2? This is a question that I've been thinking of lately (for various reasons). After reading more than a few articles, studies, and the like, I've found a few things that I want to crowd-source. I'm not advocating anything, just putting out some things I found and I'm not a medical doctor so I may be wrong about my understandings and, most importantly, I'm not responsible for any decisions that you may make.

To begin, the most estrogenic component of the PM is miroestrol which closely mimics the properties of estrogen. A 100mg PM dose contains approximately 0.02mg miroestrol so a standard 500mg PM dose contains 0.1mg miroestrol. Furthermore, miroestrol is reported to be only a quarter as potent as E2. Given all this, how many mg's of PM are needed to be on estrogenic par with 1mg of E2?

(If I screw up any of the conversions, I'm sorry and please correct me.)

1mg E2 = 4mg Miroestrol

If 0.1mg miroestrol = 500mg PM,
1mg miroestrol = 5000mg PM

20,000mg PM = 1mg E2

Therefore, 40 PM tablets are equal to 1mg E2.

Considering most transitioning male-to-females take about 2mg - 4mg of E2 per day, that would translate to 80PM - 160 PM tablets per day to have roughly the same estrogenic potency. (DO NOT TAKE 80PM - 160 PM tablets per day or any quantity that technically exceeds the amount proscribed by Ainterol or any PM provider.)

But that's just if we consider miroestrol the ONLY PM component that is estrogenic. Which it isn't. Also included in PM are daidzin, daidzein, genistin, genistein, and puerarin. To some extent, all are estrogenic. What this means is probably that PM is more than a quarter as potent as E2. How much more? Half-as? Three-quarters-as? I don't have a clue. To get a better picture, we'd have to know the potency ratios to E2 for all the aforementioned components. Maybe, then we could begin to figure out how estrogenic PM is in comparison to E2.

Eloise, this is some good information. Thanks!

Hmmm, comparing apples to oranges comes to mind. Are miroestrol and estradiol really comparable? How are we to measure potency? Do both activate the same E-receptors? Can quantity replace quality?

If someone uses PM to grow breasts to a certain point and stalls, will taking significantly higher dosages of PM restart growth? Will taking estradiol?

Clara

Well ClaraKay I was on 3000-5000 mg PM and I started kinda slowing down.... Ive been on E2 for a week and I can say thats not a problem anymore

Really they are very close as far as how they make me feel but the E2 wins so far

I have tried smaller amounts of PM with the E2 and I can still feel the effect of the PM even while on the E2....

Hmmm, comparing apples to oranges comes to mind. Are miroestrol and estradiol really comparable? How are we to measure potency? Do both activate the same E-receptors? Can quantity replace quality?

If someone uses PM to grow breasts to a certain point and stalls, will taking significantly higher dosages of PM restart growth? Will taking estradiol?

Clara

All good questions.

Are miroestrol and estradiol really comparable?

Yes. Since miroestrol is a phytoestrogen and mimics the estrogenic properties of estrogen produced in our bodies, to the extent our bodies cannot tell the difference, the comparison can be made. But this does raise a good point: Which estrogenic properties does miroestrol mimic? E1? E3? or E2? Most of the studies examined miroestrol in comparison to E2 without ever specifying. If anyone has the answer, please please share.

How are we to measure potency?

If E2 is the best estrogen anyone can use, let's say it's 100% potent. (Obviously, that varies person-to-person because of the differences in our bodies but for the sake of this theoretical exercise, let's just over look this point.) So, if E2 is 100% potent and miroestrol is only a quarter as potent as E2, that's how I measured potency.

Do both activate the same E-receptors? (Interesting question!)

There are two variants of the estrogen receptor, alpha (ER-α) and beta (ER-β) and many phytoestrogens display somewhat higher affinity for ER-β compared to ER-α. Whereas E2 works on both.

Can quantity replace quality?

If you mean: Can a lot of PM replace the quality of E2?, all I can say is I'm not sure.

If someone uses PM to grow breasts to a certain point and stalls, will taking significantly higher dosages of PM restart growth? Will taking estradiol?

Stalling may be caused by a number of things. Maybe the person is over-flooding receptor sites with too much PM, for example. Once again, though, I don't know. Taking E2 would probably spark growth but that's a question best answered by an endo.

Eloise you're on the right track,

I've posted this a couple of times already, but E dominance slows receptor sensitivity, progesterone corrects this over burden. I've also posed a similar thread of yours, what I've found is that synthetics vs. phytoestrogens are metabolized differently. But this is your thread my dear, and I'm so impressed with your knowledge, in fact I'm so impressed with everyone's knowledge tbh.

So keep going the answers are there!


P.S. Don't forget about dexymiroestrol

http://www.ncbi.nlm.nih.gov/pubmed/21856387

Eloise you're on the right track,

I've posted this a couple of times already, but E dominance slows receptor sensitivity, progesterone corrects this over burden. I've also posed a similar thread of yours, what I've found is that synthetics vs. phytoestrogens are metabolized differently. But this is your thread my dear, and I'm so impressed with your knowledge, in fact I'm so impressed with everyone's knowledge tbh.

So keep going the answers are there!


P.S. Don't forget about dexymiroestrol

http://www.ncbi.nlm.nih.gov/pubmed/21856387

Oh, I also have to add that E2 has a half life of three hours, if you can find this info you'll get a gold star! well how about props instead!

You might find this study from Nutrition Research Journal interesting.

Bimodal action of miroestrol and deoxymiroestrol, phytoestrogens from Pueraria candollei var. mirifica, on hepatic CYP2B9 and CYP1A2 expressions and antilipid peroxidation in mice.

The aim of the present study is to investigate the impact of miroestrol and deoxymiroestrol (Fig. 1) on the regulation of hepatic CYP2B9 and CYP1A2 at both transcriptional and enzymatic levels. We hypothesized that because miroestrol and deoxymiroestrol have similar structures compared with estradiol and possess estrogenic-like activities, these 2 compounds should regulate mouse hepatic P450s in a similar manner as estradiol. Furthermore, the antilipid peroxidation activities of these 2 compounds were determined in the mouse brain to provide additional beneficial biologic activities.

Nutrition Research Journal

Happy Reading.

Denita

Half-life info: http://www.breastnexus.com/showthread.php?tid=14002&highlight=deoxymiroestrol

And thank you Denita. I'll have to give that a read.

Half-life info: http://www.breastnexus.com/showthread.php?tid=14002&highlight=deoxymiroestrol

And thank you Denita. I'll have to give that a read.

Unfortunately the OP in that thread discovered that the half life figures quoted weren't in fact for deoxymiroestrol, but in any case half life is only part of the story. More to the point is how long does it and miroestrol take in acting on estrogen receptors. As for Denita's and Lotus' links ,they are almost completely above my head.