Proviron as an aromatase inhibitor
Proviron is said to bind to the aromatase enzyme, rendering it useless. As a result, it is believed that this enzyme is no longer available (or in reduced amounts) to convert testosterone into estradiol.
The following can be read in the green book (Anabolic Steroids 1994, by Grundig/Bachmann):
Unlike the anti-estrogen Nolvadex... Proviron And Sustanon 250 prevents the steroids from aromatizing from the ground up. ... It's fair to say that Proviron gets to the root of the problem, while Nolvadex only treats its symptoms.
So the authors of the green book want to get to the root of the problem (with the help of Proviron). This is a common view, also found among Americans:
W. Llewellyn in "Anabolics 2002":
Among athletes Proviron is primarily used as an antiestrogen. ... The result is somewhat comparable to Arimidex, the drug acting to prevent the buildip of estrogen.
This is in contrast to Nolvadex, which only blocks the availability of estrogen to bind and activate receptors ...
L. Rea in "Chemical Muscle Enhancement": Proviron And Sustanon 250
Unlike Nolvadex (which only keeps estrogen from bonding with its receptors by blocking them), Proviron actually prevents the formation of estrogen.
It almost sounds as if the two of them had copied a little from the green book.
Bill Roberts is a little more cautious when he inserts the word "probably". Found under Differences Between the Antiestrogens, Anti-aromatases versus Estrogen Antagonists
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).
Is it possible that all of these luminaries are wrong on the subject of Proviron And Sustanon 250?
In a Belgian study1 published in 1991, 27 men received 150 mg of mesterolone (Proviron) daily for 12 months. As is usual in such studies, there was also a control group of 25 men who received a placebo instead of Proviron.
Hormone levels were determined before the start of the study and after 3, 6, 9 and 12 months. When measured before the start of the study, the mean values for LH, testosterone and estradiol in the Proviron group were as follows:
Testosterone: 5.1 ng/ml
LH: 5.64 IU/L
Estradiol: 60.7 pg/ml
If Proviron had the claimed aromatase-inhibiting effect, then this would have to be reflected both in the absolute estradiol value and in the ratio of testosterone to estradiol.
A significant decrease in testosterone levels was observed in the Proviron And Sustanon 250 group. The reduction varied somewhat over time, ranging from 20 to 40%. The LH value also tended to decrease
The estradiol value did not change significantly. Only a slight decrease was observed after 12 months (just over 10%).
So what can one conclude now? Proviron And Sustanon 250
Although testosterone decreases significantly, estradiol does not. The testosterone / estradiol ratio therefore shifts more in the direction of estradiol under Proviron And Sustanon 250.
An aromatase-inhibiting effect of Proviron therefore seems very unlikely. In fact, quite the opposite is the case.
Would be a very good idea if Llewellyn & Co. would make a few small corrections to their works.
Say power and strength sports are the events where results can you
expect from. Greater fat burning capacity that work like peak levels
obtained by the second dose with no accumulation over time (15). Toss,
this will restore it right back starts ...