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How A Cortisol Blocker May Affect Your Thyroid

Learn about the science behind cortisol blockers and if this class of medication is safe for your thyroid.
How A Cortisol Blocker May Affect Your Thyroid
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Cortisol is a stress hormone released by the adrenal glands. We all have cortisol in our bodies, and there are times when this stress hormone can benefit us. However, chronically high cortisol levels can have damaging effects. Cortisol blockers are medications that decrease the amount of cortisol in your body. These medications are necessary to treat health conditions like Cushing's syndrome. However, some people use them as a dietary supplement for weight loss and muscle building. Let's explore if a cortisol blocker is safe to use outside of medical purposes if you live with a thyroid condition like hypothyroidism (underactive thyroid) or Hashimoto's disease (autoimmune thyroiditis).


What is cortisol?


Cortisol is a hormone made and released by the adrenal glands that sit just above the kidneys. This hormone is often referred to as the stress hormone because it is released when we are stressed. 


Cortisol drove the "fight or flight" response for our primitive human ancestors. When we sensed a threat like a predator, the hypothalamus in the brain signaled the adrenal glands to release cortisol, so blood and energy could shift to the organs necessary for saving our lives—primarily the heart, lungs, and muscles. Another hormone released in this process is adrenaline, which helps direct blood flow away from "non-critical" tissues like the gut, sending it to the heart.


Of course, this "fight or flight" system is still present in our modern human bodies and shows up in various scenarios. For example, many people fear public speaking and feel their "fight or flight" systems activate when approaching a group of people. Regrettably, chronic stress can also lead to higher cortisol levels for sustained periods, leading to health complications down the road. 


The following may also impact cortisol levels:

  • Temperature
  • Shift work
  • Poor sleep, or lack thereof
  • Exercise
  • Diseases, infections, and trauma
  • Obesity
  • Certain medications like steroids and birth control pills
  • Pregnancy
  • Alcohol and caffeine
  • Nutrient deficiencies

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Why do some people take cortisol blockers?


Cortisol blockers are a medication class that prevents the release of cortisol in your body. These medications are a common treatment for a rare condition called Cushing's syndrome, where the body produces too much cortisol.


However, some claims also suggest that cortisol blockers help with weight loss and fat reduction, which is why you may see non-prescriptive cortisol blockers marketed by fad dietary and supplement companies. Additionally, some people also take cortisol blockers when they are weight training so that cortisol does not slow down muscle building. 


According to Katherine Zeratsky, R.D., L.D., with the Mayo Clinic, there is no concrete evidence that cortisol blockers help with weight loss or are helpful in strength training. Indeed, the FDA and Federal Trade Commission have fined some dietary supplement companies that make cortisol blockers because they had false claims about providing rapid and permanent weight loss. The information we have on the dietary use of cortisol blockers is purely anecdotal and not research-based. 


Are cortisol blockers harmful to your thyroid?


Given how little we know about cortisol blockers outside of their effectiveness in treating medical conditions like Cushing's, it is best to avoid products labeled as cortisol blockers. In addition, people who live with a thyroid condition should be especially wary of cortisol blockers, as manipulating your cortisol levels can directly affect your thyroid.


Cortisol increases thyroid-stimulating hormone (TSH). When cortisol levels are high, it signals the thyroid gland to stop producing as much thyroid hormone. Cortisol also restricts the conversion of the thyroid hormone T4 to the active thyroid hormone T3, which is the form of thyroid hormone that cells can use.


With this, it may seem plausible that taking a cortisol blocker could help increase thyroid hormone in your body. However, there is no research to show that cortisol blockers effectively regulate thyroid hormones. And, because the body so tightly controls hormones, it comes as no surprise that manipulating one hormone may have consequences on other hormone levels.


Why decreasing cortisol is vital for your health


We know that cortisol certainly plays an essential role in our survival. However, it can also have damaging effects on our bodies, especially when we sustain higher than normal cortisol levels for some time. 


One of the big things cortisol does is inhibit the effectiveness of insulin, causing blood sugar levels to rise. This mechanism is vital in response to a threat as it gives our body a quick energy boost. Over time, however, it can lead to chronic health problems like type 2 diabetes, eye problems, or kidney disease.


Cortisol also suppresses the function of the gastrointestinal tract, reproductive system, and immune system. Again, in response to an immediate threat, this is important for our survival. Still, with time, it can lead to other health conditions like infertility and gastrointestinal disorders. It may even increase one's risk for autoimmunity.


As you may gather, some of the most significant risks of having sustained high cortisol levels include poor sleep problems, weight gain, anxiety, and chronic health conditions. Thus, it is evident that curbing cortisol levels is vital for your health and wellbeing. 


While taking a cortisol blocker is not the answer to warding off conditions like weight gain and anxiety, it is crucial to reduce your cortisol levels by other means. For example, it is necessary to eat well, make your schedule more manageable, and carve out time for regular exercise and mental breaks. Of course, working with a healthcare professional to treat any underlying chronic health conditions like hypothyroidism is also vital for reducing the stress load on your body. 


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Julia Walker, RN, BSN

Clinical Nurse

Julia Walker, RN, BSN, is a clinical nurse specializing in helping patients with thyroid disorders. She holds a Bachelor of Science in Nursing from Regis University in Denver and a Bachelor of Arts in the History of Medicine from the University of Colorado-Boulder. She believes managing chronic illnesses requires a balance of medical interventions and lifestyle adjustments. Her background includes caring for patients in women’s health, critical care, pediatrics, allergy, and immunology.

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