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Arimidex (Anastrozole) PCT 101: The Bodybuilder’s Guide

Discover the benefits and side effects of using Arimidex (Anastrozole) for PCT, including dosing recommendations, buying options, and more.
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Disclaimer: The following guide is based on my personal experience and does NOT promote the illegal use of PEDs.

Arimidex is an aromatase inhibitor that has long been used by bodybuilders while running a steroid cycle containing steroids that aromatize – that is, they bring about the conversion of testosterone into estrogen.

But what makes this aromatase inhibitor so good and so useful for anyone on an AAS? Are there any downsides to using Arimidex? Are there better options for you? I’ll reveal the answers to these questions and many more in my guide to Arimidex.

Let’s get into it!

What is Arimidex?

Arimidex could be the most popular ancillary taken by anabolic steroid users. As a steroid user, you would know that estrogen is vital for your health and your results. But I bet you also fear it!

Arimidex Aromatase Inhibitor
Arimidex Aromatase Inhibitor

Arimidex is here to act as your estrogen controller, and by using it wisely, you can move your estrogen levels up or down as needed. This makes Adex a truly powerful ancillary that many of us find essential!

History and Overview

The only approved use by the FDA for Arimidex is for hormone-receptor-positive early breast cancer in postmenopausal women. It also has approval as an advanced breast cancer treatment for women who haven’t responded to Nolvadex.

Arimidex initially got its FDA approval in 1995. But it was back in 1987 that a British company developed this AI called Imperial Chemical Industries – the same company that developed Nolvadex.

Like many drugs, Arimidex is sometimes prescribed off-label (which means the FDA does not approve its use) to men who are on testosterone replacement therapy (TRT) for the purpose of lowering estrogen levels.

While most studies on Arimidex have focused on its breast cancer treatment effectiveness, off-label treatment for male hypogonadism has received some scientific attention – and this is what is of the greatest interest to us. One study that I’ll mention below makes it clear that Arimidex is useful for a lot more than solely as a breast cancer treatment.

Mechanism of Action

Arimidex is an aromatase inhibitor, so its core function is to block androgens (testosterone) from converting to the estrogen hormone. It does this by binding to the aromatase enzyme. Studies show it takes 1mg per day of Arimidex to suppress aromatase to over 96% (far more than we would want on-cycle).

A study on men using Arimidex off-label alongside TRT found that this AI is effective at sustaining testosterone levels[1]. It’s also been shown that AIs can increase levels of LH, follicle-stimulating hormone (FSH), and testosterone in men with low testosterone[2].

Effects of Arimidex (Benefits) for Men

The number one benefit of Arimidex for men is that it gives you protection against estrogenic side effects of aromatizing hormones like testosterone, which can convert into estrogen. Some guys are naturally higher aromatizers than others. You might convert more testosterone into estrogen than I do, resulting in:

  • Water retention/bloating
  • Gynecomastia
  • High blood pressure

Getting tuned in to how YOU respond to aromatizing steroids can take a little while, and that means you might be experimenting with your Arimidex dosage until you get the effects you’re looking for.

What does this mean for you?

Well, it means all of the effects and benefits of Arimidex will relate to the above symptoms, and this is centered on one function: Reducing your estrogen levels. This is the core benefit of Arimidex for us. The associated control of gynecomastia and water retention are the direct result of reducing the estrogen that has come about from the process of aromatization.

Aromatase Inhibitors vs. SERMs: What’s the Difference?

Besides both being used to control estrogen in some way, aromatase inhibitors (AIs) and SERMs are two very different types of drugs. There are some similarities:

  • Both AIs and SERMs are used to treat breast cancer as their primary medical purpose.
  • Both have been used off-label to support testosterone function in men.

Here are the most important ways they differ:

Mechanisms of Action

  • AIs block the aromatase enzyme to stop the conversion of testosterone into estrogen.
  • SERMs target specific estrogen receptors where they can either block or promote estrogenic activity in specific tissues.

Side Effects

  • Some SERMs can have a beneficial effect on your cholesterol, while AIs can increase cholesterol levels. This is important for us to consider when we use any AAS that negatively affects cholesterol.
  • AIs are more likely to cause muscle and joint pain as well as bone loss due to a drastic reduction in estrogen levels.
  • SERMs come with a small risk of blood clots.


  • Many SERMs are excellent for both on-cycle and PCT use.
  • AIs are considered best for on-cycle estrogen control only and are rarely used for PCT.

Arimidex for PCT

New steroid users will often assume that Arimidex is the best drug to use for PCT. But in fact, it’s best not to use Arimidex or any AI during PCT (instead, SERMs and HCG should be taken to stimulate testosterone).

Once you’re comfortable using Arimidex and know how you respond, it’s an excellent way of managing or even micro-managing your estrogen on-cycle. Making minor adjustments to your dosage up or down as needed can make all the difference to how you feel on-cycle and how well you can manage (and prevent) estrogenic side effects.


Medical doses of Arimidex for the treatment of breast cancer are usually much higher than we would want to take. The standard recommended medical dose is 1mg daily[3]. If male steroid users were to take such a high dose, we can expect our estrogen levels to crash very quickly and severely.

At the other end of the spectrum, some doctors will prescribe Arimidex for men who are on testosterone replacement therapy, and this can be at doses as low as 1mg per week. Here are the dosages of Arimidex you should be considering:

Arimidex Dosage On-cycle

I can’t state strongly enough how important it is that your on-cycle Arimidex dose is dialed in according to the:

  • the compounds being used, their ability to aromatize, and their dosages
  • your personal response to Arimidex

Starting with 0.25mg every three days is a good starting point, but it won’t suit everyone or every cycle. From there, you can (and should) adjust the dosage as needed.

Too much water retention or gyno worrying you? Boost the dose to 0.5 or, in more extreme cases, to 1mg every three days and monitor both positive and negative effects. If gyno signs start developing, even a single 1mg dose can clear it up quickly, and you can discontinue using the AI.

Taking too much Arimidex will have you feeling horrible pretty fast, and it’s a sign not to ignore: drop that dosage back to 0.5mg or 0.25mg if you start getting symptoms of low estrogen.

Arimidex Dosage for PCT

Arimidex is not recommended for PCT use despite the fact it has been shown to increase testosterone – however, these studies concerned primarily elderly men with permanently low testosterone levels.

Arimidex is perfect for estrogen control on-cycle, but if we use it during PCT, its estrogen-crushing effects will destroy your hormone recovery. I’ve heard about some guys using this AI for PCT, though (perhaps they had no access to SERMs, which is what we should be using for PCT). A dosage of 0.5mg daily or even just 0.25mg is a good starting point to evaluate the effects.

Suppose you’re going to continue on TRT after stopping your steroid cycle. In that case, Arimidex can be very useful, and it’s here we can consider similar doses to those used for medical TRT purposes – 1mg per week is often enough to take care of all your needs.

Dosing Schedule, Half-life, and PCT Length

Arimidex has an approximate half-life of 2 days. Most bodybuilders will take it every three days, and you can expect it to start working quickly. On cycles where aromatization is extreme, some will take Arimidex every two days or even every day – but do not try that strategy unless you absolutely know what you’re doing – estrogen crushing is a real risk with daily Arimidex dosing.

Since we will rarely want to use Arimidex as part of PCT, your use of it will typically stop at the end of your steroid cycle. If you are running Arimidex during PCT, a standard cycle length still applies for 4-6 weeks.

Proper Administration and Timing

Arimidex comes in a simple pill form, which is easy to take. The big question a lot of guys have is whether you should take Arimidex for your entire cycle or only when you need it. There are MANY variables to consider, the first one being what AAS you’re using and how they impact your estrogen levels.

In most cases, I only want to use Arimidex WHEN NEEDED. This means starting Arimidex if I get some nipple puffiness or tingling to stop that gyno in its tracks. I might only need two or three doses, and then I’ll stop taking Arimidex. This also helps with reducing any negative impacts on your cholesterol.

Your timing will also depend on how long your AAS takes to kick in and start causing estrogenic issues – long-ester testosterone, for example, can mean waiting around three weeks until you need to start thinking about taking Arimidex.

Arimidex vs. Other PCT Options

Some of our other best PCT options are also excellent on-cycle ancillaries. This will include primarily SERMs for PCT, while there are other AIs you can choose for on-cycle use, and it’s worth comparing these to Arimidex.

Arimidex vs. Enclomiphene

Enclomiphene has become a favored SERM for PCT because it’s fantastic at kickstarting testosterone production after a suppressive cycle.

Enclomiphene SERM
Enclomiphene SERM

When it comes to on-cycle use, Enclomiphene doesn’t hold a candle to Arimidex. In fact, we really don’t want to use Enclomiphene on-cycle at all.

  • Arimidex will stop water retention and gynecomastia in their tracks by lowering your total estrogen levels.
  • Enclo, on the other hand, only targets specific estrogen receptors and has zero effect on your total estrogen level.

What does this mean for you? You don’t have to choose between Enclomiphene and Arimidex because they can be incredibly beneficial for different purposes: Arimidex for on-cycle estrogen control and Enclomiphene for PCT testosterone recovery.

Arimidex vs. Aromasin

There are a lot of opinions out there between guys who love or hate either Arimidex or Aromasin. There’s nothing wrong with preferring one over the other, but there’s a ton of misinformation as well.

Aromasin Aromatase Inhibitor
Aromasin Aromatase Inhibitor

Both are very effective AIs and very popular. Most of the opinion is based on how each of us responds to each AI. Many guys find the risk of estrogen crashing is less with Arimidex compared to Aromasin. Arimidex works fast, and this lets you quickly make changes that will take effect rapidly and allow for small adjustments.

Because Aromasin is what’s known as a suicidal AI (irreversibly binds to the aromatase enzyme, unlike Arimidex, which binds reversibly), we tend not to get any estrogen rebound when stopping Aromasin at the end of a cycle. This means some guys find it easier to come off Aromasin without any side effects. Arimidex can require more care in coming off so you don’t get rebound symptoms – this can require tapering your dose slowly.

Aromasin has a shorter half-life (1 day), so it is typically dosed daily instead of once every three days with Arimidex. And a big one: Aromasin has been shown to have a “neutral effect” on total cholesterol, while Arimidex can raise your LDL and total cholesterol levels[4].

Arimidex vs. Letrozole

Letrozole is very similar chemically to Arimidex, but it mainly excels at reversing gyno rather than being useful for water retention.

Letrozole Aromatase Inhibitor
Letrozole Aromatase Inhibitor

Letrozole could very well be the best AI to take for gyno, and that is its main purpose. But Letrozole is very strong compared to Arimidex, and it’s mostly used by guys who are what we’d call “heavy aromatizers,” where other AIs aren’t strong enough to combat gyno.

There have even been studies comparing the effects of Arimidex and Letrozole (on women with breast cancer). One study found that Letrozole suppresses estrogen more so than Arimidex in the breast and circulating estrogen levels[5]. Needless to say, it’s going to be easier to crush your estrogen with Letrozole, and I’d use it with caution and only for a very good reason or if you can’t get hold of Arimidex or another AI.

Arimidex Side Effects in Men

Most men will tolerate Arimidex well, and you can definitely use it without any notable side effects – as long as you’ve got your dosage dialed in and, ideally, you’re monitoring estradiol levels through bloodwork (including before you start taking this AI). A long list of side effects is recognized for this AI when it’s used for medical purposes.

But here’s the thing: When Arimidex is prescribed for female breast cancer patients, we have to keep in mind that this is usually a long-term treatment – a 5-year Arimidex treatment is standard.

The role of estrogen in males and females is different. What this means is that male users of Arimidex are unlikely to be at risk of many or even any of the medically listed side effects of Arimidex. Here, I will focus on the sides that are known to affect some men who use Arimidex on-cycle:

Increased Cholesterol

Arimidex can raise your cholesterol – this includes increasing LDL and total cholesterol. Studies on the long-term use of Arimidex showed this to be a problem[6]. But at the same time, the patients recorded an increase in HDL (good) cholesterol levels. This was, however, after one year – much longer than most of us will use Arimidex continuously.

Combined with the use of AAS, which can also increase your cholesterol, you will want to do regular bloodwork to monitor your lipids on-cycle.

Low or Crashed Estrogen

The risk with taking any AI is causing too much of a reduction in your estrogen levels, and it’s here that we have the main side effect risks of Arimidex. Us males need some estrogen to function properly. You do not want to crush your estrogen levels through the misuse of an AI.

Thankfully, low estrogen-related side effects are easily avoided with the proper use of Arimidex. With its fast-acting effects, you can quickly adjust your dosage and see a recovery from these side effects within a matter of days. Some of the noticeable problems that could indicate your estrogen has got too low on Arimidex are:

  • Joint pain
  • Loss of sex drive
  • Erectile dysfunction
  • Low energy/fatigue
  • Depression or low mood
  • Bad memory and poor concentration
  • Lack of motivation
  • Anxiety

Yes, many of the signs of low estrogen are similar to those of low testosterone! But if you’re using Arimidex and experience the above, lower your dose slightly and evaluate your response.

Where to Buy Arimidex?

Buying Arimidex should not be a complicated process for you, although it also won’t be the cheapest ancillary you ever buy. Most of our favorite steroid or SARMs suppliers will carry one form of Arimidex or another.

Many will sell it under the name Anastrozole – whether it be generic pharmaceutical grade, underground labs, or in liquid form from a research chemical supplier.

Availability of Arimidex

Arimidex is one of the easier ancillaries to buy, and you should find it widely available. Of course, having a prescription is very unlikely, considering the only approved medical use for this AI is for older women. So obtaining the ultimate pharmaceutical grade Arimidex will depend on what sort of contacts and sources you have.

Underground lab and chemical research suppliers will all have a good supply of Arimidex, but quality can always be hit and miss. I would only stick with the most reputable sellers who have been around a long time and/or those who have a solid reputation among the bodybuilding community.

Arimidex is a prescription-only drug in most major countries, including the US, UK, and Australia. This means you can’t legally buy it over the counter at a pharmacy or anywhere else.

Still, it’s not classed as a controlled or prohibited substance in the same category as anabolic steroids. So if you’ve got Arimidex in your possession, you’re not going to come under the same scrutiny as if you were carrying steroids.

Arimidex isn’t a banned substance by WADA or other organizations as it hasn’t been recognized as having any performance-enhancing benefits.

Typical Pricing

We can get used to the most common ancillary drugs being very cheap to buy. But Arimidex is actually quite expensive, and on a per-tablet basis, you’ll pay a lot more for this AI than we do for most SERMs.

1mg tablets are the standard product, and if you can get a pharmaceutical grade (either branded or generic), you can expect to pay $80 or more for a box of 30 tablets. Underground labs can vary substantially in pricing – anywhere from almost $1 per tablet up to more than $7. All I will say is you CAN get excellent UGL Arimidex at high purity, but I would avoid the very cheapest suppliers to minimize the risk of a bunk product.

Finally, if research chemical grade is your preferred (or only) option, then a 30ml bottle of 1mg/ml concentration costs $40 and up. Some companies will offer discounts on bulk vial purchases.

Final Thoughts

When something is as popular as Arimidex has been for so long, you know we’re on to something good. Plain and simple: Arimidex is such a useful tool, and I won’t go without it. Just don’t make the error of thinking you always need to be on it the entire time on cycle.

Unless I’ve done a certain cycle a few times and know exactly what to expect and when in terms of sides, I always prefer to wait until those first signs of estrogenic side effects show up before taking an Arimidex dose. And this strategy works well thanks to Arimidex taking effect so quickly.

Don’t crush your estrogen, monitor your cholesterol, and stick with the dosages that experts recommend, and you will find Arimidex to be an invaluable tool in your arsenal.


— Furious Joe

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Joe Robles a.k.a Furious Joe

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What I talk about here is something I've done. From anabolic steroids to SARMs to peptides and ancillary drugs, I've done it at some point in my life, and I can relate.

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