Aromasin (Exemestane)

Do you need to use Aromasin on your next Anabolic Steroid cycle? Find out below.

One of the major shifts in the use of anabolic steroids came with the introduction of Aromatase Inhibitors in the mid-1990s.

For the first time, a steroid user could avoid using a Selective Estrogenic Modulator Receptor or SERM as their first line of defense against unsafe estradiol levels. 

Aromatase Inhibitors suppressed the Aromatase enzyme which would otherwise convert any excessive testosterone into estrogen, to maintain homeostasis.

Preventing this conversion works phenomenally well in many situations.

There are two drugs that are primarily used as an Aromatase Inhibitor in a steroid cycle. That’s Arimidex and Aromasin.

Today, we will talk about Aromasin and how, why and when to incorporate it into your steroid cycle.

That’s if it is necessary at all.

If you have always wondered how to use an AI or whether you need to use it at all, then you are at the right place.

Sit back and enjoy the read.

What is Aromasin?

aromasin bodybuilding

Aromasin is the brand name for Exemestane, a steroidal aromatase inhibitor drug that’s used to treat breast cancer in post-menopausal women.

Breast cancer cells piggyback on Estrogen to spread in the mammary tissue. By blocking the aromatization process, Aromasin prevents the cancer cells from growing. Or slows down the growth in advance stages of the disease.

In a steroid cycle, it works in a very similar fashion. Some anabolic steroids have a strong estrogenic nature, due to which they convert readily into Estrogen via the aromatase inhibitor.

An increase in Estrogen amplifies the risk of forming gynecomastia in men. It can also lead to a spike in blood pressure, which in extreme stages can cause severe problems.

Using an aromasin during steroid cycles with such compounds can help users prevent estrogenic side effects.

Which anabolic steroids convert via the aromatase inhibitor?

Exemestane dosage

Here’s a quick glance at the commonly used anabolic steroids and the likelihood of them converting into E2 via the aromatase inhibitor.


Highly estrogenic in nature. And without an AI, there is a high likelihood of it converting into estrogen and causing estrogenic side effects. You will have to watch out for any red flags closely if you are running a test cycle without Aromasin. In fact, it is highly recommended that you stock up on aromasin before beginning your test cycle.


The Nandrolone hormone, which includes Deca Durabolin with the slow release, long acting ester and Trenbolone, displays very low estrogenic activity. Trenbolone in fact, does not aromatize at all. Deca has an aromatization rate of just 20% of Test. However, both these compounds display a strong progestin nature, which makes them more than capable of triggering estrogenic activity in mammary tissue. So, using an AI during a Deca cycle will save you from potential Gyno. Most users use Cabergoline during a Trenbolone cycle.

Boldenone Undecylenate or Equipoise:

Aromatizes at 50% the rate of Test. But it’s still possible to get gyno with Equipoise. Stock up on Aromasin and only use it if you notice any symptoms of high E2.


No estrogenic activity. In fact, Masteron is quite popular due to its anti-estrogenic effects.


No estrogenic activity. Primobolan does not aromatize.


Winstrol does not aromatize.


It’s a DHT-derived steroid that does not aromatize. Nor does it have a progestin nature. Despite this, it mysteriously stimulates estrogen receptors in mammary tissue and is very capable of causing gyno. However, since Anadrol does not aromatize, using an AI is not necessary and will be ineffective against the side effects.


Strong estrogenic compound. Very likely to cause Gyno and severe water retention if you do not use an AI during a Dianabol cycle.

Using Aromasin during the cycle vs. using it during PCT

aromasin pct

The verdict on this one is still out there.

A lot of seasoned steroid users use Aromasin to dial down their E2 levels during the cycle if they are using an estrogenic compound. But the PCT ‘drug of choice’ is usually Nolvadex or Clomid, or both. Aromasin is rarely used during PCT.

But some users have recently started to use Aromasin during PCT as it helps increase the production of endogenous testosterone by stimulating the pituitary gland to release more Leutinizing Hormone and Follicule Stimulating Hormone.

Also, Aromasin has a unique trait. It also stimulates the release of Insulin Like Growth Factor 1, which is very desirable for some athletes.

However, things aren’t as simple as they sound when you are dealing with hormonal drugs.

Aromasin can reduce your estrogen levels by as much as 85%. That in turn can be counterintuitive when you are trying to restore your body’s hormone levels to normalcy. When your E2 levels crash, it can cause some severe side effects.

So, irrespective of what bro-science you read on the internet, stick to Nolva and Clomid for the PCT. Reserve the use of AIs for the cycle.

Aromasin vs. Arimidex

Aromasin vs. Arimidex

The next conundrum faced by steroid users is whether to use Arimidex or Aromasin.

Well, it’s subjective.

Aromasin can reduce Estrogen levels by 85%. Arimidex reduces it by 80%. The difference is negligible.

Having said that, Arimidex is supposedly more difficult to dose accurately. (Based on anecdotal reviews)

There’s a high possibility that you might use a very low, ineffective dose or use a dose that can crash your E2 levels completely. The dosage has to be monitored continually to avoid a rebound.

Aromasin on the other hand is a suicide inhibitor that you can dose and forget. (

However, there are over 40 polymorphisms of CYP19A1, the protein that’s commonly called aromatase. And for this reason, different people aromatize at different rates.

This makes it very difficult to put a ballpark number to the dosage.

Start with the lowest dose of 6.25mg a day. And then increase or reduce if needed. Ideally, you’ll need bloodwork prior and after the cycle to determine how effective the dose was.

But more experienced users can dose accurately based on how they feel during the cycle. If you feel that the nipples are puffy or itchy, it’s a red flag.

Side effects of Aromasin

Aromasin is usually very well tolerated in normal doses (6.25 – 20mg a day).

However, in some users it can cause lethargy, fatigue, hot flashes, muscle cramps, joint pain and high blood pressure.

Watch out for any sides that become unmanageable.

Exemestane side effects