Arimidex - Pain Caused by Crashing E2 or Another Reason?

[Cataceous]

... Third generation ai's don't have this effect, but they do seem to effect progesterone significantly.

Here are some papers that show reduced progesterone and/or progesterone receptor (PR) expression from the use of anastrozole:

Anastrozole Reduces Progesterone and Proliferation Index in Short Term Hormone Therapy. A Prospective Placebo Double Blind Study.

Short-term Anastrozole Therapy Reduces Ki-67 and Progesterone Receptor Expression in Invasive Breast Cancer: A Prospective, Placebo-Controlled, Double-Blind Trial.

Effect of Aromatase Inhibitors versus Clomiphene Citrate for Ovulation Induction in Infertile Women with Ovulatory Dysfunction (PCO).

...
Almost every man I've seen test their progesterone on trt are deficient. I find it more likely that ai-related sides are from reducing already low progestenic activity, rather than slightly reducing an already high estradiol.

The first two studies relate to the expression of the progesterone receptor in biopsies of ER-positive invasive breast cancer in post-menopausal women taking 1 mg per day of anastrozole. How exactly does this support the claim of reduced serum levels of many hormones in males taking order-of-magnitude lower doses?

The third study says that women taking clomiphene end up with higher progesterone levels than those taking letrozole. Their phrasing suggests they believe that clomiphene is increasing progesterone, not that letrozole is lowering it: "In the present study, clomiphene citrate significantly increased estradiol and progesterone levels compared to letrozole in cycle one and cycle 3. ...."

I also get the impression that TRT may suppress progesterone. I've been supplementing with it for some time to maintain normal levels. I believe it's helpful, but not any miracle cure.

...
Progesterone: 1.4 nmol/L (0.44 ng/ml) (Range: < 0.474 nmol/L)

First off, the range for male progesterone is wrong.
...
Despite being 3x above the 'healthy' range, my progesterone levels fall inline with most data that investigates male progesterone levels, with mine being considered high-normal.
...

It's an apples-to-oranges comparison if you're not using the same assay by the same lab.

 

[PhantomFear]

I appreciate your points, and I understand the limitations of those studies. I wasn't trying to claim that arimidex is dropping guys progesterone levels in half. I was suggesting that the side effect's associated with low doses - which are attributed to a reduction in estrogen, despite serum estrogen remains relatively unchanged, and often remaining high - are more likely a product of reduced progesterone and the expression of it's receptor.

If 1mg a day is causing a ~50% drop in progesterone receptor expression, you don't think 1mg a week is going to have any effect on prog at all? My point isn't that it's going to drop absolute serum levels by a large margin; more that any drop, even if small, is going to have a large impact on a man if they are already deficient in prog - as is the case for most men on TRT.

Out of curiosity, what dose of prog are you using? I never claimed it was a miracle cure, because I don't think any exogenous hormone is. I've taken it myself on TRT and got okay-ish results, but nothing that impressive. I found pregnenolone a much better option than progesterone whilst on T.

The < 0.141 nmol/L reading on TRT was run by the exact same lab that produced the 1.4 nmol/L reading only four weeks apart. I've never seen a man not test > 0.141 nmol/L when using the same lab - even those on TRT.

Saya noticed the same thing when the lab ranges first got changed. You can read his comments here.

 

[Cataceous]

...
If 1mg a day is causing a ~50% drop in progesterone receptor expression, you don't think 1mg a week is going to have any effect on prog at all? My point isn't that it's going to drop absolute serum levels by a large margin; more that any drop, even if small, is going to have a large impact on a man if they are already deficient in prog - as is the case for most men on TRT.
...

Considering there's an enormous body of research on anastrozole, it would be a lot more convincing if you could find studies demonstrating a statistically significant effect on serum progesterone. What is the proposed mechanism for this effect? Is it direct, or indirect via estradiol?

...
Out of curiosity, what dose of prog are you using? I never claimed it was a miracle cure, because I don't think any exogenous hormone is. I've taken it myself on TRT and got okay-ish results, but nothing that impressive. I found pregnenolone a much better option than progesterone whilst on T.
...

I inject 0.5 mg PROG subQ nightly. I never had very good results with pregnenolone. The latter seems to heighten anxiety.

...
The < 0.141 nmol/L reading on TRT was run by the exact same lab that produced the 1.4 nmol/L reading only four weeks apart. I've never seen a man not test > 0.141 nmol/L when using the same lab - even those on TRT.

Saya noticed the same thing when the lab ranges first got changed. You can read his comments here.

Since that post LabCorp has raised the top of its reference range to 0.5 ng/mL. Without harmonization it's unknown how this compares to methods showing higher values, e.g. the one cited by Wikipedia, originally 0.27-.9 ng/mL, but now 0.2-1.4 ng/mL.