Relative Potency of Type 1 and Type 2 Aromatase Inhibitors
Product Aromatase Inhibition (%) Residual Aromatase (%)
Formestane/
4-Androstenoldione 91.9 8.1
------------------------0---------------------------------------0--------------------------------------0
Aromasin/
Exemestane 97.9 2.1
------------------------0---------------------------------------0--------------------------------------0
Cytadren/
Aminoglutethimide 90.6 9.4
------------------------0---------------------------------------0--------------------------------------0
Arimidex/
Anastrozole 96.7 3.1
------------------------0---------------------------------------0--------------------------------------0
Femara/
Letrozole 98.7 1.3
-----------------------0---------------------------------------0---------------------------------------0
So far it would appear that Letrozole is the leader, huh?
Anti-Estrogens And IGF-1 Production
GH (Growth Hormone) is like a master hormone for tissue growth and fat regulation due to its own intrinsic qualities and its propensity to be converted into or trigger the production and release of Growth Factors. Of these Growth Factors, one of the best known in regard to muscle growth is IGF-1 (Insulin-Like Growth Factor-1).
As most are aware by now, IGF-1 is a powerful anabolic and anti-catabolic hormone. Whether in pre-contest mode or packing on the mass, the amount of circulating and stored IGF-1 an athlete maintains plays a powerful role in the results achieved. Obviously as IGF-1 levels decrease so does the potential for packing on the beef, and the amount of lean tissue lost during calorie-restricted periods increases as well. (Not good)
Estrogen, and more so estradiol, can trigger GH release from the pituitary gland. Aromatase inhibitors decrease the amount of circulating estrogen/estradiol and estrogen receptor antagonist keep estrogen out of the specific pituitary receptors. So in many regards the use of anti-estrogens can effect IGF-1 production and in some cases affect the number of IGF-1 receptors our tissues posses.
Product Effect Percentage
Formestane/
4-Androstenoldione Increases IGF-1 26%
-------------------------0----------------------------------0-----------------------0
Femara/
Letrozol Increases IGF-1 24%
-------------------------0----------------------------------0-----------------------0
Arimidex/
Anastrozole Decreases IGF-1 18%
-------------------------0----------------------------------0-----------------------0
Nolvadex/
Tamoxifen Decreases IGF-1 23.5%
-------------------------0----------------------------------0-----------------------0
Faslodex/
Fulvestrant Decreases IGF-1 70%
-------------------------0----------------------------------0-----------------------0
Cytadren/
Aminoglutethimide Increases IGF-1 27%
-------------------------0----------------------------------0-----------------------0
Aromasin/
Exemestane Increases IGF-1 28%
-------------------------0----------------------------------0-----------------------0
Hmmm, so now we have some major points in favor of Cytadren, Aromasin and Formestane.
Other things to consider pre-contest or simply as a matter of achieving desired results at any point in the pursuit of freak status include…
When attempting to evaluate "the best" choice for any item, the question of specific-intent should come into play first. If you asked for solely my opinion, then I would choose the product that covered the greatest number of needs for specific-intent or goal(s). Personally I prefer Formestane (under whatever name the product is provided, in the purest most active form).
Why?
Formestane increases IGF-1 secretion and activity.
Formestane decreases the number of progesterone receptors (inhibits the trenbolone and "deca-dick" type side effects and increases fat loss)
Formestane inhibits 91.9% of aromatase enzyme production
Formestane increases HPTA activity similar to HCG and Clomid together
Formestane is anabolic and androgenic (At 500mg weekly the product is similar in effects to 250mg of Primobolan Enanthate)
Formestane is a "suicide inhibitor" of aromatase. Specifically this means that it will irreversibly bind to the aromatase enzyme and permanently deactivate it
Formestane (The sterile injectable form) possesses a 4-day half-life
Formestane decreases SHBG 34% thus increasing androgen activity.
Formestane inhibits DHT (dehydrotestosterone) formation and activity.
Formestane possesses 1% of the binding affinity of DHT to DHT receptors
Formestane has been shown to decrease prostate concerns such as BPH.
Formestane has been shown to continue to increase HPTA function above natural levels even after 22 weeks of continuous administration.