Exos (active agent - exemestane) is a very strong and very potent steroidal aromatase inhibitor of the suicidal type.  Exos is extremely effective at 25mg daily for the reduction of serum circulating estrogen levels by 85%.

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.

The fact that exemestane is a steroidal aromatase inhibitor is the prime reason as to why it is a suicidal aromatase inhibitor that remains permanently bound to the aromatase enzyme.

Exemestane is a steroidal aromatase inhibitor which keeps it from negatively affecting your lipids like some other non-steroidal AI’s. It is also not liver toxic, and can be run for longer lengths of time without negative effects. This makes it a better option to run on cycle from a pure health standpoint.

Another benefit on cycle is that exemestane lowers SHBG which increases bioavailability of testosterone and, respectively, cycle efficiency.

Finally, exemestane is a perfect drug for post-cycle therapy. There is simply no other aromatase inhibitor that can compare in terms of its effects on HPTA recovery. In studies, exemestane dosed at 25mg per day increased total testosterone by 60% in only 10 days.

Even better than that, is the fact that free (bioavailable) testosterone increased over 100% in the same time frame! In addition, exemestane also increases IGF-1 levels. There is no estrogen rebound from exemestane, and it is also a very powerful and effective treatment for gynecomastia.  All of this makes Exos a perfect choice for post cycle therapy as well as on cycle estrogen control.

The half-life of Exos is only about 9 hours, and clears quickly. However, because of how effective exemestane is at eliminating aromatase enzymes (80-90% after administration), estrogen levels will remain low up to 72 hours after a single dose of 25mg.

Post-cycle therapy (PCT)