If you want to learn how estrogen blockers work, how effective they are, and what kind of side effects they cause, then you want to read this article.

You’re probably here because you want to gain muscle or lose fat faster and you’re wondering if estrogen blockers can help.

You’ve probably also seen fantastical claims about what these drugs and supplements can do to your physique.

You’re not alone.

Thousands of others are searching about estrogen blockers every day, too, because they’ve heard the same blarney that brought you here.

And in this article, we’re going to get to the bottom of it all.

Now, the war against estrogen is at a fever pitch these days because it’s riding on the coattails of its big brother, testosterone, which is also on a lot people’s minds.

It’s common knowledge that raising your testosterone levels can help you gain muscle and strength and lose fat faster, which is why more and more people are snapping up testosterone booster supplements and signing up for testosterone replacement therapy.

Most people also know that raising testosterone levels also raises estrogen levels, and that high estrogen levels is generally associated with higher levels of body fat, erectile dysfunction, and feminizing effects like gynecomastia.

Furthermore, it’s also often assumed that lowering estrogen levels in and of itself can improve body composition and virility, and especially in people that are “estrogen dominant” and thus incapable of gaining any considerable amount of muscle and strength.

Is all the estrogen hype warranted, though? And are estrogen blocking drugs and supplements effective, safe, and legal, like many people claim?

Well, here’s the long story short:

Synthetic estrogen blockers absolutely work. With the right drugs, you can plunge your estrogen to rock-bottom levels.

Unfortunately, however, that isn’t going to help you build a better physique, and it’s going to screw up your health, to boot.

And what about natural estrogen blockers?

Well, they’re even more worthless in that they won’t even significantly impact your estrogen or testosterone levels, let alone help you gain muscle or lose fat faster.

By the end of this article, you’re going to understand all this and more, so let’s start at the top…

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What Is Estrogen?

Estrogen is a hormone, which is a chemical messengers that your body uses to communicate with cells.

You can think of hormones as outgoing mail that contains orders on how cells are supposed to behave. When they reach a cells’ “mailboxes”–hormone receptors–the orders are carried out.

In the case of estrogen, it’s produced primarily in women’s ovaries (the adrenal glands and fat cells also produce small amounts), and it affects the body in many ways, including:

What Are Estrogen Blockers?

Strictly speaking, estrogen blockers are a group of drugs that reduce either the production and/or effects of estrogen in your body.

Some common ones are…

  • Arimidex (anastrozole)
  • Aromasin (exemestane)
  • Cytadren (aminoglutethimide)
  • Femara (letrozole)
  • Nolvadex (tamoxifen)
  • Clomid (clomiphene)

The term “estrogen blocker” has also come to include natural supplements, though, that contain various ingredients purported to positively impact your hormone profile, including resveratrol, grape seed extract, curcumin, maca, wild nettle root, and 3,3′-Diindolylmethane.

There are many more natural substances that are purported to balance or reduce estrogen levels, but we can save ourselves time and just cut to the chase:

None of them have ever been proven to work in healthy humans.

In short, they’re just as much of a scam as natural testosterone boosters.

The bottom line is natural estrogen blockers aren’t going to meaningfully alter your hormones or help you get jacked faster, so not only should you spend your supplement money elsewhere, you should actively boycott any fitness “gurus” or companies that claim otherwise.

Pharmaceutical estrogen blockers are a whole other story, though.

Most of these drugs were developed to help combat breast cancer because estrogens can be carcinogenic in female breast tissue, and the science here is clear:

They work remarkably well–in some cases, they can reduce estrogen levels by 90% or more.

I don’t want to put you to sleep with too much technical jargon, but estrogen blocking drugs accomplish their purpose in one of two ways:

  1. By suppressing your natural estrogen production
  2. By making the estrogen that you produce unable to affect your body

The first point is straightforward enough, but if you’re wondering how number two works, allow me to explain. 🙂

A large portion of the estrogen in men’s bodies is created from testosterone using an enzyme called aromatase.

Many estrogen blockers simply render this enzyme ineffective, thereby reducing the amount of testosterone that gets turned into estrogen.

Others work by denying estrogen entry to cells’ “mailboxes” (receptors), leaving it to wander around aimlessly in your system and eventually be eliminated.

Why Do Fitness Folk Take Estrogen Blockers?


The reasons many gymrats take estrogen blockers are simple:

  1. They’re on steroids, and/or;
  2. They think it’ll improve their body composition

The reason people on steroids also take estrogen blockers is because synthetic testosterone and other anabolic drugs also greatly increase estrogen levels.

Thus, estrogen-blocking drugs are included in steroid cycles to prevent problems associated with elevated estrogen levels like water retention and bloating, “bitch tits,” fat gain, and the like.

The reason everyday gymgoers take these drugs and, more commonly, supplements is because they believe it’ll help them get bigger, leaner, and stronger, faster.

The idea is that by suppressing estrogen’s effects in the body, you can enhance testosterone’s, and even increase total testosterone levels by reducing the amount that’s naturally converted into estrogen.

This, in turn, is supposed to increase muscle growth.

Well, as I mentioned earlier, this might sound good in theory but it doesn’t pan out. Let’s find out why.

Estrogen Blockers and Building Muscle

It’s often claimed that estrogen blockers can help you build muscle faster by increasing your testosterone levels.

Well, research shows that synthetic estrogen blockers do indeed raise testosterone levels, sometimes by as much as 50%.

Interestingly though, these drugs don’t appear to raise testosterone levels in skeletal muscle, meaning that you don’t see the muscle-related benefits normally associated with increased testosterone production.

Scientists aren’t completely sure why this is, but it explains why estrogen blockers have never been proven to enhance body composition.

Estrogen Blockers and Performance

Another way that estrogen blockers are sold to hopeful bodybuilders is the claim that they’ll enhance workout performance, thereby enabling you to push yourself harder and gain muscle faster.

Well, as of now, no studies have demonstrated that estrogen blockers can improve athletic performance, and, in fact, there’s good reason to believe that they could actually worsen it.

One of the most common side effects of estrogen blockers is fatigue (because estrogen heightens attention and sharpens focus), and that makes for notably worse workouts.

This is why many people on powerful cocktails of anabolic steroids and estrogen blockers often experience chronically low energy levels despite getting adequate sleep.

Estrogen Blockers and Steroids


Guys and gals on steroids don’t include estrogen blockers in their steroid cycles because they’re anabolic per se.

They use them so they can take larger amounts of anabolic steroids with fewer side effects.

The base of any “steroid stack” is always testosterone, and it’s not uncommon for people to increase their testosterone levels to over 10 times what their bodies produce naturally.

This, of course, raises estrogen levels as well, because the more testosterone you have floating around in your system, the more will be converted to estrogen.

Next often comes other anabolics like deca-durabolin, Dianabol, and Sustanon, which only further raise estrogen levels.

Thus, an estrogen blocker is more or less a necessity if you want to take a few grams of #dedication per week.

(Certain steroids, though, like Primobolan, trenbolone, and drostanolone [Masteron] don’t impact estrogen levels, which is one of the reasons they’re very popular.)

Now, an estrogen blocker can often be left out if you’re only on a low dose of testosterone, but that’s not going to deliver the types of results that people expect when they get on steroids. For that, you have to stack and dose aggressively, which is going to inevitably raise your estrogen levels higher than you want them to be, requiring the addition of estrogen blockers.

Are Estrogen Blockers Safe?


Research has shown that estrogen blockers are likely safe if used for short periods (a few months), but there’s good evidence that long-term use could lead to health problems.

For example, studies show that these types of drugs can increase the risk of bone demineralization and fracture, osteoporosis, and joint pain, as well as elevated cholesterol and triglyceride levels, an increased risk of heart disease and stroke, and deep vein thrombosis.


Estrogen blockers are also known to increase the incidence of hot flashes, constipation, vertigo, skin itching, nausea, and depression.

All in all, not a pretty package.

It is worth mentioning, however, that most of the human research we have on these drugs was conducted with women who were fighting breast cancer, so we may not see the same effects in healthy people.

There are also no long-term studies conducted with men, so that’s just a big question mark.

That said, you could absolutely count on experiencing at least some negative side effects if you were to take estrogen blockers. Just as artificially increasing estrogen levels would disrupt your physiology to one degree or another, so would artificially decreasing them.

Yes, estrogen blockers are legal to purchase, but they typically require a prescription as their main use is for cancer treatment.

The Bottom Line on Estrogen Blockers


If you’re like most people, you came here because you’re considering buying natural supplements that claim to lower estrogen levels and thereby help you improve your body composition.

Well, you can skip them all.

(The same can be said for natural supplements of any kind that purport to enhance your hormone profile, by the way–they’re all more or less worthless.)

That said, there are a handful of drugs that can greatly reduce your estrogen levels. These are the types of estrogen blockers that many people on steroids use to minimize unwanted side effects.

While these drugs work, they also won’t help you gain muscle or strength or lose fat faster. The only drugs that can do that are anabolic steroids.

So, instead of trying to speed up your progress by “hacking” your endocrine system with estrogen blockers and other supplements or drugs, focus on the basics of proper diet, training, and rest, and stay patient, and you’ll do great.

What’s your take on estrogen blockers? Have anything else you’d like to share? Let me know in the comments below!