Anti Estrogen Or Anti Aromatase
A lot of info is banded about on which is better Arimidex or Nolvadex etc...
What does "anti-estrogen" mean? How are anti-estrogens like Cytadren, Clomid,
and Nolvadex different from each other? Is Proviron an anabolic steroid, or not?
Anti-estrogens are drugs which act to reduce estrogenic activity in the body.
This can be done either by reducing the amount of estrogen, or by reducing the
activity of whatever estrogen is present.
Competitive aromatase inhibitors, such as Cytadren, Arimidex, and probably
Proviron, bind to the same binding site on the aromatase enzyme that
testosterone does. By doing this, they allow less testosterone to bind to
aromatase. So, less testosterone is converted to estradiol (estrogen).
Here's an important thing: the effectiveness of competitive inhibitors decreases
as the amount of the normal substrate increases. Suppose that you had equal
amounts of inhibitor and normal substrate in the blood, and they bound to the
enzyme equally well. Then the inhibitor would at any moment be taking up half
the sites that the normal substrate otherwise would, so it would reduce
conversion rate by 50%. But if the amount of substrate is increased 10 times
while the amount of inhibitor remains the same, then the inhibitor would be out
competed by the more numerous substrate molecules. It would therefore be rather
For example, with more testosterone molecules available, and similar binding
strengths, the enzyme will mostly bind testosterone. It will then mostly be
working to produce estrogen. To obtain the 50% reduction we had before, then the
amount of inhibitor would also have to be increased 10 times.
To be really effective, the inhibitor must either be present in higher
concentration than the normal substrate, or must bind more tightly.
With Cytadren or Proviron, it takes quite a lot of inhibitor to out compete high
testosterone levels. With Arimidex, rather little, even 1 mg/day, can be
sufficient because it binds so strongly.
The other general approach is estrogen receptor antagonism. If a molecule binds
strongly to a hormone receptor, but does not activate that receptor and makes it
unresponsive to the normal hormone, then it is a receptor antagonist. Clomid
(clomiphene) and Nolvadex (tamoxifen) follow this approach. These drugs are very
similar structurally. They are both what are called triphenylethylenes, and are
not steroids. The differences are relatively minor, but seem to affect an
important characteristic of these compounds: drug metabolism.
Both tamoxifen and clomiphene are metabolized to other related compounds which
can be estrogenic or anti-estrogenic. Both act as estrogens in bone tissue,
perhaps after metabolism, which is a very useful property for female patients,
for whom these drugs are usually intended. (Otherwise, an anti-estrogen could
lead to osteoporosis.) Tamoxifen seems particularly prone to acting as an
estrogen in the liver, which may account for reduced IGF-1 levels seen when this
drug is taken.
Users generally seem to agree that when tamoxifen is used, gains are a little
less than what otherwise would be expected. (Let's not take this too far though:
many people have made great gains while using tamoxifen as an anti-estrogen. And
it's always hard to say what "would" have been the case if a drug had not been
included.) I've heard nothing but good about clomiphene, though.
Proviron, an anabolic steroid, is particularly interesting. I suspect that it
not only acts as an anti-aromatase but in an unknown DHT-like anti-estrogenic
manner. This might involve estrogen receptor downregulation for example. In any
case, aromatase inhibition and/or Clomid don't seem to give the same effect on
appearance and muscle hardness as when Proviron is included.
How much of these agents is needed for effective estrogen suppression?
Again, it depends on the dose of anabolic/androgenic steroids (AAS) and it
depends what type of AAS is being used.
With Primobolan or trenbolone there is no need for these drugs.
With nandrolone, an aromatase inhibitor will be of no use, because aromatase is
not used in the aromatization of nandrolone. A rather small amount of estrogen
receptor antagonist can be useful. 12.5 to 25 mg Clomid would be plenty for 400
With testosterone, stacking of an aromatase inhibitor and an estrogen receptor
antagonist will give the best results. Cytadren use should not exceed 250 mg/day
in my opinion. This alone would not be sufficient for say 1 g/week or more of
testosterone. With such a dose, ideally one would add in 50 mg/day Clomid.
Proviron at 100 mg/day could substitute for the Cytadren. Or Cytadren and
Proviron can be used in combination, 125/50 or higher, together with 50 mg/day
For lower doses of testosterone, proportionally less antiestrogens can be used.
Arimidex is very effective but extremely expensive. 1 mg/day of this is at least
as effective as 250 mg/day Cytadren. If a milligram per day cannot be afforded,
use of half a milligram would allow Cytadren use to be cut in half, which may be
How does Clomid "stimulate" testosterone production at the end of the cycle?
It really doesn't. Rather, by acting as an estrogen receptor antagonist, it
reduces the inhibition that results from elevated estradiol levels. This helps
return LH to normal levels, which helps testosterone to return to normal levels
(if the testicles have not atrophied).
How does HCG help?
Acts as an LH receptor agonist, thus substituting for LH. It does nothing to
help the hypothalamus and pituitary. Thus, it can be effective during the cycle
to help avoid testicular atrophy, but is not best used in the taper when one is
attempting to restore LH production. Increases in natural testosterone,
stimulated by the HCG, will act to inhibit LH production. Thus, you can see
where HCG use is counterproductive in the taper itself.
Can Clomid, taken throughout a cycle, completely eliminate inhibition?
I do not believe so. There is also androgenic inhibition mediated by the
androgen receptor, which has nothing to do with the estrogen receptor.
Androgenic inhibition is unavoidable and cannot be helped by estrogen receptor
antagonists. However, use of Clomid throughout a cycle can definitely reduce the
degree of the inhibition and allow a speedier recovery at the end of the cycle.
Is it safe to take Clomid for so many weeks? I heard it should only be taken for
The two week idea comes from the fact that medically its main use is to help
women with fertility problems. Because of the menstrual cycle, there are only
certain times of the month when there is any chance of ovulation. It is
pointless, then, for these women to take the drug for more than two weeks at a
time. Some have misconstrued this to apply to males.
Men have taken the drug in clinical studies for a year continuously. It is a
rather safe drug.
Why do you say not to use more than 250 mg/day of Cytadren?
Cytadren has two main therapeutic activities. At high doses, such as a gram per
day, it is a very effective inhibitor of the enzyme desmolase, which is required
for all steroid production, and is rate limiting for the production of cortisol.
So the drug is very useful for treating patients with Cushing's Syndrome, who
produce abnormally high levels of cortisol.
It is also an inhibitor of aromatase, and it is a better aromatase inhibitor
than a desmolase inhibitor. About 250 mg/day is sufficient for fairly good
inhibition of aromatase, resulting in only fairly low levels of desmolase
As dosage increases, aromatase inhibition does not improve much, but desmolase
inhibition increases greatly.
Even at 250 mg day, there is still significant desmolase inhibition. Other side
effects, such as lethargy, may bother some individuals even at this dose.
Why is desmolase inhibition bad? I have read that cortisol is the enemy of our
muscles, and we want to reduce it.
Those articles are written by people trying to sell you alleged
While abnormally high levels of cortisol are indeed muscle wasting, abnormally
low levels of cortisol do not result in extra muscle growth, and cause joint
You've talked about tapering off Cytadren. Why?
There is a feedback mechanism for production of cortisol. Low levels of cortisol
enhance release of corticotropin releasing hormone from the hypothalamus, and
ACTH from the pituitary. Both will result in higher production of cortisol.
So moderate inhibition of desmolase will temporarily reduce cortisol, but soon
it will be back to normal as this feedback mechanism compensates.
If you then suddenly discontinue the drug, then these elevated ACTH levels will
result in abnormally high cortisol for a time, until the body adjusts again.
This can be avoided simply by tapering down over about a week.
Should Cytadren be taken all at once, or in divided doses?
Because the half life is only 6 or 8 hours, if the drug is taken only once, then
through part of the day there will be little drug in the system, and little
I think the best approach is to use half the dose on arising (or an hour or two
afterwards) to get blood levels from a somewhat low level up to the desired
maintenance level. This would then be followed by quarters of the dose at 7 or 8
hour intervals twice after that.
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