Ok guys - I have been researching the misconceptions of progesterone lately and it came up in a thread with some other people. Since I spent the time writing it there I have just decided to cut and copy my response on that thread to this one for you guys to read.
------ This was the response ------
I am glad you asked - I have been researching this a bit actually and have come up with some interesting things about progesterone, it's effects on the body, and how to deal with it appropriately.
Progesterone is found in men and is actually beneficial in a lot of ways contrary to popular belief. It is the primary precursor of adrenal cortical hormones and testosterone. Males synthesize progesterone in amounts less than women (in fact men have about half what women do) but it is still vital. It also can be very useful for steroid users in preventing prostate cancer due to large amounts of testosterone. Progesterone regulates testosterone levels in males just as it does estrogen levels in females. It does this by preventing the body from converting testosterone to di-hydro testosterone. It does this by inhibiting the enzyme 5-alpha reductase.
As for gyno, progesterone alone does not cause gyno. But at any rate - gyno, in the literal sense of the word is not a feminizing characteristic. It's a fatty build up in the breast.
BUT....if you ask me I don't think that progesterone alone causes gynecomastia. Everyone thinks that there is such thing as progesterone induced gyno....I tend to disagree. I have been studying this a bit and have found that it seems that progesterone is only a risk for gynecomastia when in combination with C-17 components or others that cause activity at the progesterone receptor.
There have been studies done regarding the interaction with spironolactone. Spironolactone, trade name - Aldactone, was originally developed in the early 1970's as a competitive antagonist of aldosterone for the treatment of hyperaldosteronism, edematous states, and hypokalemia. In studies where Spiro was being test to combat heart failure it was noticed that the drug had interactions with the testosterone and progesterone receptors, thus causing gynecomastia. There were noticeable differeces in the levels of pre-existing progesterone in the trial patients. The difference correlated with those who did, and those who did not run into problems with gynecomastia.
So to make a long story short - it's my theory that nobody gets gyno from deca cycles alone converting to progesterone. I dont think gyno can be derived from progesterone levels alone. I think this excess progesterone is a vital part of the process BUT I would argue that it is the 17aa components that activate the progesterone receptors and let the excess amounts of progesterone start to create gynecomastia. I cannot possibly say what other elements would activate the receptors that would lead to increased risk of gynecomastia. I am sure that 17aa'a are not the only ones though. So how would you combat that risk?
RU-486. I know you didn't ask HOW RU-486 works but I figure if I explain how it is that RU-486 helps prevent and eradicate gyno, you would understand that RU-486 is most likely NOT the only compound to have this capability. RU486 (mifepristone) is a synthetic steroid related to progesterone. Unlike most progestins that mimic the action of progesterone, RU-486 blocks the action of progesterone. In other words, RU-486 renders progesterone biologically inactive.
RU-486 is a progesterone antagonist. It binds to the progesterone receptor, and in so doing prevents progesterone itself from occupying its receptor. Thus the gene transcription normally turned on by progesterone is blocked, and the proteins necessary to begin the process of gynecomastia are not synthesized.
So, that being why RU-486 actually helps progesterone RELATED gyno, it is also true that other progesterone antagonists will help in the same way. The only other commercially available progesterone antagonists that I know of is Onapristone (ZK 89.299). The only difference between these two progestrogen antagonists, is the difference in antiglucocorticoid activities for the glucocorticoid receptor (GR). RU-486 provokes this action while Onapristone does not. So, my point being that RU-486 actually blocks corticoid action, thus - the healthiest choice of progesterone related gyno combat tools, would actually be Onapristone. For which I am trying to research what the effective dose would be.
So my conclusion is that RU-486 is, contrary to popular believe, NOT the only way to combat this gyno and in fact - probably not even the healthiest way.
whew...sorry I know you didn't ask for all that but i's something I have been stewing on for a bit and I think what I am finding is very interesting.
Mike
**Note - another important fact about progesterone.
Progesterone is a natural and powerful inhibitor of the 5-alpha reductase enzyme. This means - that when on a testosterone/deca cycle and worried about DHT....proscar may not be the answer....
You don't need to take saw palmetto or proscar with a Test/Deca cycle to prevent testosterone from converting to DHT. Deca acts as progesterone which actually inhibits 5 alpha reductase far more effectively than Proscar and Saw Palmetto which are the more standard agents employed in traditonal and natural medicine.
Just a thought......