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What is the Truth About Estrogen Blockers (aromatase inhibitors)?

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Many physicians and their patients know very little about estrogen blocorskers' actual effect (aromatase inhibitors /AI's). It is all too common for doctors to give these drugs to guys undertaking testosterone replacement therapy. Anastrozole (Arimidex ®), exemestane (Aromasin ®), and letrozole (Femara ®) are popular drugs that men take to stop the production of estrogen with a misguided belief that it's beneficial to their health. 

When our hormone experts talk to our patients for the first time, many ask if we prescribe estrogen blockers, and the simple answer is no. Most guys find this unusual and expect us to throw a box of Arimidex ® in with their prescription. When we explain the reality of what estrogen does, the benefits it has, and how dangerous it is to block, they never look back.

Why Don't We Prescribe Estrogen Blockers?

Estrogen is a byproduct of testosterone via an enzyme called aromatase. It, therefore, makes sense that administering testosterone will also increase estrogen levels. Testosterone exhibits its many benefits via this aromatase conversion, and most physicians and patients are so set in their ways they have no idea this is the case.

If estrogen was so bad, why are there no studies in the past 40 years exhibiting the adverse effects it supposedly has on the body? Compare that to the numerous studies showing the harm caused to the body when estrogen is blocked. 

When you give estrogen, you see an increase in bone density, a reduction in cholesterol, and reduced cardiovascular disease. Men treated with aromatase inhibitors experience bone density loss (fractures), elevated cholesterol, and increased heart disease risk. 

In one report (1) it states:

"Osteoporosis and low bone mass are currently estimated to be a major public health threat for almost 54 million U.S. women and men aged 50 and older (2010 data). Among the 54 million, 10.2 million adults are estimated to have osteoporosis."

As men age, testosterone production slows, as does estrogen production. Along with that, the protection it offers the body reduces as well. By blocking estrogen with medication, you risk losing those benefits.

  • Erectile function and libido
  • Increased bone density
  • Regulation of fat mass vs. lean mass
  • Brain function
  • Lipid metabolism 
  • Skin health

We also now understand that testosterone's many health benefits are a direct result of estrogen; this is the exact reason we do not prescribe estrogen blockers. Estrogen is prescribed to women to help them maintain bone density and support brain function, heart health, immune system, sexual function, and libido, all benefits that it brings to men, so why on earth would you take drugs to block it?

There are a few cases when estrogen blockers such as Arimidex ® are justified in small doses, for example, increased sensitivity to estrogen, which causes sore nipples and breast swelling. But, for the most part, you should never prescribe estrogen blockers with testosterone.

As we get more and more patients moving from their traditional, outdated TRT to our bioidentical daily treatment, we find patients who have estrogen levels as low as '0' because of their doctors gave them estrogen blockers. These guys are completely unaware that they run a higher risk of heart disease, bone density loss, Alzheimer's disease, high cholesterol, and memory loss.

A few clinicians also claim raised estrogen in men causes an increased risk of prostate cancer. Again there is no medical literature to back this up, and this is purely speculation. One of Male Excel's lead doctors, Dr. Rouzier, states

''I am not aware of any studies in the last 50 years that have demonstrated an increased risk of prostate cancer is due to elevated estrogen levels.' If estrogen does indeed cause cancer, then the standard practice would be to block it in women too, which of course isn't the case."

Why Do Guys Take Estrogen Blockers?

Testosterone therapy increases estrogen; there is no hiding this, but think about this fact. When you were 25 years old, and your testosterone levels were at their peak, so were your estrogen levels; why didn't doctors block estrogen when you were younger? Because it is good for you!

Estrogen is well known as a female hormone, and yes, women do produce it in far more significant amounts. Contrary to popular opinion, as a man, estrogen will not make you 'womanly,' or grow moobs (gynecomastia) and if you medically stop estrogen production, it certainly won't make you more manly!

Estrogen is Not the Enemy!

Many people taking testosterone to lose weight or to build muscle see estrogen as an enemy. They are led to believe, the more testosterone they take, the more is converted to estrogen and therefore wasted. Bingo! taking an estrogen blocker is their answer, thereby increasing testosterone. This approach is absolutely wrong for numerous reasons. 

Many fail to understand that fat is the issue, not estradiol (a form of estrogen). Excess fat, especially visceral fat around your belly and internal organs, produce an aromatase enzyme that converts testosterone from fat into estradiol. This increased estradiol level sends a signal to the brain to slow testosterone production, with the brain assuming the estradiol is coming from excess testosterone. 

So, fat cells increase aromatase activity, creating more estradiol. Generally, men with excess fat have low testosterone. Through this aromatase cycle, you can conclude that the estradiol is made from fat and not testosterone. It is not estradiol that is an issue; it is the fat.

So one would then assume that the next logical step is to block the estradiol with aromatase inhibitors. Absolutely not! Studies show that if you do, you increase the chance of heart attack. Yes, it will increase testosterone by stopping the estrogen conversion but as said before, your body needs estrogen, and blocking it can cause all sort of health issues such as:

  • Sexual dysfunction (ED, low desire, low libido, and reduced satisfaction).    
  • Poor cardiovascular health.  
  • Altered cholesterol levels (good and bad). 
  • Prostate issues
  • Decreased bone mineral density (osteoporosis)  
  • Poor insulin resistance (decline in lean muscle mass, increased belly fat, and diabetes risk).  
  • Compromised brain health and cognition issues. 

Being overweight is dangerous. Fat kills; it causes heart disease, diabetes, and often an early exit from this world. Many people believe that you can increase testosterone by blocking estradiol and use that to help burn fat and increase muscle. This concept sounds great, but unfortunately, for those who take this route, testosterone relies on estradiol to sensitize your muscles to testosterone! 

The answer is not to stop the estrogen. The answer is to give testosterone. Testosterone helps your body combat all the negatives that lead to visceral fat and help you lose this fat. We should be screaming the long term health benefits of optimizing testosterone levels from the rooftops along with its close and necessary relationship with estrogen.

To sum up, blocking estrogen (estradiol) is 100% the wrong thing, especially when undertaking testosterone replacement therapy. In particular, for those who are overweight, the answer is funnily enough to give estradiol in the form of testosterone. Testosterone replacement therapy increases muscle and reduces fat. Testosterone, DHT, and estradiol all work together to protect you against all sorts of age-related diseases. Next time someone tells you you should be on estrogen blockers, you can now correct them with confidence!

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Disclaimer: Information provided on this page is not a substitute for professional medical advice, diagnosis, or treatment. If you have any questions or concerns about your health, please feel free to contact us or consult your doctor.