Carhartt, the only reason I was thinking of putting nolva and aromasin together is because of an article I found: Aromasin with Nolvadex
I've always been in favor of using Nolvadex during PCT, along with an Aromatase inhibitor (AI), because reducing estrogen levels has been positively correlated with an increase in testosterone (7) so in my mind, it's be beneficial to increase testosterone by as many mechanisms as possible while trying to recover your endogenous testosterone levels after a cycle. SO which Aromatase inhibitor (AI) do we use? Letro or A-dex? Well, why don't we just keep using whichever one we used during the cycle, and add in some Nolvadex? Unfortunately, Nolvadex will significantly reduce the blood plasma levels of both Letrozole as well as Arimidex (8). So if we choose to use one of them with our Nolvadex on PCT, we're throwing away a bit of money as the Nolvadex will be reducing their effectiveness. This, of course, is where Aromasin comes in, at 20-25mgs/day.
Aromasin, at that dose, will raise your testosterone levels by about 60%, and also help out your free to bound testosterone ratio by lowering levels of Sex Hormone Binding Globulin (SHBG), by about 20% (12)';SHBG is that nasty enzyme that binds to testosterone andrenders it useless for building muscle. But what about using it along with Nolvadex for PCT?
Difference Between Type-I and Type-II Aromatase Inhibitors
To understand why Aromasin may be useful in conjunction with Nolvadex while both Letro and A-dex suffer reduced effectiveness, we'll need to first understand the differences between a Type-I and Type-II Aromatase Inhibitor. Type I inhibitors (like Aromasin) are actually steroidal compounds, while type II inhibitors (like Letro and A-dex) are non-steroidal drugs. Hence, androgenic side effects are very possible with Type-I AIs, and they should probably be avoided by women. Of course, there are some similarities between the two types of AIs;both type I & type II AIs mimic normal substrates (essentially androgens), allowing them to compete with the substrate for access to the binding site on the aromatase enzyme. After this binding, the next step is where things differ greatly for the two different types of AI's. In the case of a type-I Aromatase inhibitor (AI), the noncompetitive inhibitor will bind, and the enzyme initiates a sequence of hydroxylation; this hydroxylation produces an unbreakable covalent bond between the inhibitor and the enzyme protein. Now, enzyme activity is permanently blocked; even if all unattached inhibitor is removed. Aromatase enzyme activity can only be restored by new enzyme synthesis. Now, on the other hand, competitive inhibitors, called type II AI's, reversibly bind to the active enzyme site, and one of two things can happen:
1.) either no enzyme activity is triggered or
2.) the enzyme is somehow triggered without effect.
The type II inhibitor can now actually disassociate from the binding site, eventually allowing renewed competition between the inhibitor and the substrate for binding to the site. This means that the effectiveness of competitive aromatase inhibitors depends on the relative concentrations and affinities of both the inhibitor and the substrate, while this is not so for noncompetitive inhibitors. Aromasin is a type-I inhibitor, meaning that once it has done its job, and deactivated the aromatase enzyme, we don't need it anymore. Letrozole and Arimidex actually need to remain present to continue their effects. This is possibly why Nolvadex does notalter the pharmacokinetics of Aromasin (11).
Conclusion
Before we close the book on Aromasin, it's worth noting that you can (and should) still use one of the non-steroidal AIs during your cycle to reduce estrogen, if necessary. When you are ready for PCT, you can then switch over to Aromasin and still experience the full effects of an Aromatase inhibitor (AI), since there is no cross-over tolerance experienced between steroidal and non-steroidal AIs (9). Since Aromasin is about 65% efficient at suppressing estrogen (10), it's certainly a very powerful agent, especially considering you won't experience reduced effectiveness because of your concurrent use of Nolvadex or from any sort of tolerance developed by using other AIs on your cycle(9). There is also a decent amount of preclinical data suggesting that Aromasin has a beneficial effect on bone mineral metabolism that is not seen with non-steroidal agents, and it may also have beneficial effects on lipid metabolism that are not found in the non-steroidal Letro and A-dex (9).
Finally, as we're going to be using Nolvadex for PCT anyway, and we ought to be using an Aromatase inhibitor (AI) with it for maximum recovery';I think Aromasin- considering it's compatibility with Nolvadex and beneficial effects on bone mineral content and lipid profile, has finally stopped being the black sheep of AIs and found a home in our cycles.
