Estrogen is an unwanted by-product of Steroid use. In some tissues of the male body, there is a nasty little Enzyme called the “Aromatase” Enzyme. This Enzyme is responsible for turning Testosterone and other male hormones into female ones like Estrogen, and Estradiol or other girly-like hormones. An abundance of Female hormones in the male body can cause a whole list of bad side-effects, like male breast tissue growth and water retention. Bodybuilders use a lot of different drugs and compounds to combat these bad side effects. The best way to keep Estrogen from causing problems is to make sure it is never created in high amounts in the first place. Using a compound that inhibits the Aromatase Enzyme is a sure way to make sure Testosterone and other Steroids are never converted into side-effect causing Estrogen.
A compound that inhibit the Aromatase Enzyme from creating Estrogen is called an Aromatase Inhibitor, or AI for short. There are a lot of options out there when it comes to AI's (Aromatase Inhibitors), and Aromasin is certainly one of the most popular options for bodybuilders that cycle steroids for a number of reasons.
Aromasin is a suicidal Aromatase inhibitor, which makes it a better choice than other AIs. Exemestane binds with aromatase enzymes and then subsequently permanently disables the enzyme by destroying it.
Aromasin is a steroidal AI which keeps it from negatively affecting your lipids like other non-steroidal AIs. It is also not liver toxic, and can be ran for longer lengths of time without negative effect. This makes it a better option to run on cycle from a pure health standpoint. Aromasin will not hurt your gains on cycle like other AIs, but may actually help them. Another benefit on cycle is that steroidal AIs lower SHBG which increases the ratio of free to bound testosterone. What that means during your cycle is a very positive impact on your gains. This (in a sense) makes your Anabolic Androgenic Steroids more bio-available.
The half-life of Aromasin 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. This is why aromasin is very effectively dosed every other day. In one study, users were still 40% below baseline estrogen values 72 hours after their dose. This makes aromasin very versatile for dosing and not require more frequency.
Now, the place where Aromasin really shines is in post cycle therapy (PCT). There is simply no other Aromatase inhibitor that can compare in terms of its effects on recovery. We already mentioned how Aromasin lowers SHBG, which increases free testosterone.
What does that mean?
In a study, Aromasin dosed at 25mg per day increased total testosterone by 60% in only 10 days. Even better than that, is the fact that free (useable) testosterone increased over 100% in the same time frame! In addition, Aromasin also increases IGF-1 levels. There is no estrogen rebound from Aromasin, and it is also a very powerful and effective treatment for gynecomastia. All of this makes Aromasin a no-brainer for post cycle therapy as well as on cycle estrogen control.