Aromatase inhibitors are the compounds that serve to reduce estradiol levels in blood by eliminating the production of estradiol through binding to and disabling the aromatase enzyme, which is responsible for the conversion (or aromatization) of androgens into estradiol. Suicidal aromatase inhibitors serve to permanently inhibit and disable the aromatase enzyme to which it is bound to. This renders the enzyme inactive forever. The body will eventually manufacture more aromatase enzymes, but the currently-bound enzymes are bound indefinitely, eliminating any risk for estrogen rebound. This is the main difference compared alongside two other major aromatase inhibitors: anastrozole and letrozole, which are non-suicidal aromatase inhibitors that are only bound to the aromatase enzyme for limited time periods. If a non-suicidal aromatase inhibitor is halted too abruptly, the circulating inhibited aromatase enzymes that have not been metabolized out of the body will then become free again, and begin aromatizing androgens into estrogens at an often rapid rate. This is not the case with Exos.
HCG within the medical field is primarily administered via intramuscular (IM) injections, although it can also be administered subcutaneously, which has also become just as frequent as IM injections. Studies have found that when intramuscular and subcutaneous injections of HCG were compared, the results were almost the exact same for both, indicating almost no difference between the two  . The only difference between the two methods of injection is the difference in the rate of release from the injection site and the time required for peak blood plasma levels to be reached (6 hours for IM, and 16 – 20 hours for subcutaneous). The majority of anabolic steroid users will elect to inject HCG subcutaneously.