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Why Estrogen Blockers are Prescribed for TRT Patients?

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Written by

Science & Humans

Medically approved by

Medically approved by

Maria Jacob

Last updated

Sunday, November 7, 2021

If you've been on TRT for a while, you may have heard the word "estrogen" thrown around a lot. And if you're like us, you might be wondering: What is it, exactly?​

Estrogen is a hormone that's produced in both men and women. It plays a role in bone metabolism, as well as cardiovascular health and reproductive development. In short, it helps keep your body running smoothly—and when levels get too high or low, things can start going haywire pretty quickly!​

So what does this mean for men who are taking testosterone replacement therapy (TRT)? Well, the good news is that testosterone does not aromatize—which means that when it gets into your body, there’s no conversion from testosterone to estrogen (the opposite of what happens with women). That said, external testosterone from TRT after a while might increase estrogen levels from aromatization which needs to be countered. Too much estrogen can lead to side effects such as gynecomastia or male breasts among other side effects. ​

Men are from Mars and women might be from Venus, but hey, we all share the same hormones, but in different proportions. Estrogen (E) is also crucial for men’s health as much as women's though. Maintaining hormonal balance of different hormones as nature intended while optimizing deficits should be the goal of TRT for men. ​



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One of the reasons TRT patients are monitored diligently at Science&Humans via blood work and quarterly check ups is also to monitor estrogen levels. Means not eliminating estrogen from the body, but making sure the proper proportions of hormones are maintained for optimum health. ​

Testosterone is the most significant hormone for male sexual development and function. Naturally in males, testosterone levels decline with age, and estrogen levels increase. When large fluctuations of testosterone production occur, such as when anabolic steroids are injected, this creates an imbalance of hormones in the body. The body then corrects such an imbalance by aromatization or converting testosterone into estradiol, a form of estrogen. ​

Higher the levels of anabolic steroids imbibed, higher amounts of estrogen synthesized. Bodybuilders inject high doses of anabolic steroids, hence the aromatization of testosterone into estrogen is also very high. ​

Estrogen is synthesized from testosterone. TRT over a period increases testosterone which can lead to excess estrogen in men which is not a good thing. ​

Aromatization is the biochemical process in which an aromatase enzyme catalyzes or speeds up the conversion of testosterone into estradiol, the fundamental pathway for the synthesis of estrogens. ​

Why is it a necessary hormone for men?

Estradiol is crucial to male sexuality. If estradiol is not in balance with testosterone, problems will start to be noticed with sex drive, the ability to have an erection, and the production of sperm. High estrogen levels in males also increase risk of other conditions such as diabetes and cancer.

Estrogen is also crucial for executive functioning, impulse control, intelligence, controlling anti-social behavior as well as bone health. In fact, it is produced in skin, brain and penis in a man’s body which shows that it plays an important role in man’s health as well. But over-production of estrogen is counter-productive to TRT.

Why does estrogen spike affect testosterone replacement therapy?

Obesity - Obese men may convert the testosterone from TRT into estrogen, which will actually reduce the benefits of testosterone replacement.

High levels of E in the body is corrected by reducing Luteinizing Hormone(LH) and Follicle Stimulating Hormone(FSH) secretion. These two are crucial for natural synthesizing of testosterone and sperm generation. Means high E will actually reduce natural testosterone production in the body.

And then there is this aromatase gene which naturally produces excess E in some men. TRT has to be administered with estrogen blockers for such cases.

Estrogen blockers are also known as Aromatase inhibitors. Usual meds prescribed are:

  • Arimidex (chemical name: anastrozole)
  • Aromasin (chemical name: exemestane)
  • Femara (chemical name: letrozole)

While excess E needs to be controlled, abusing estrogen blockers by taking OTC dubious preparations, supplements, herbs is counter-productive to one’s health since estrogen has an important role in men’s health. A trained clinician is best left on deciding medication.

Further reading

Understanding the Importance of Regular Testosterone Checks

Understanding the Importance of Regular Testosterone Checks

Men may want to think about getting their hormone levels checked this year for a number of reasons.

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Can Testosterone Replacement Therapy Help with ED ?

Can Testosterone Replacement Therapy Help with ED ?

Low levels of testosterone and poor blood flow to the penis can contribute to erectile dysfunction (ED). TRT and PDE5 inhibitors can be taken with him to improve outcomes ...

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Testosterone Cypionate versus Testosterone Enanthate

Testosterone Cypionate versus Testosterone Enanthate

Testosterone injections are recommended for low-T treatment, but avoiding peaks and valleys in testosterone levels is the best option. Two popular options are subcutaneou ...

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