Hidden Cause #21 Why You STILL Have Low Thyroid Symptoms-High Cortisol Blocking Receptors

Dr. David Clark, DC – Raleigh-Durham-Chapel Hill thyroid expert, explains how high Cortisol causes Low Thyroid symptoms.

Hidden Cause #21 why you STILL have low thyroid symptoms even though you may be taking thyroid medication, and even though your lab tests may look normal is…

High cortisol suppressing thyroid hormone receptors.

Now, we’ve talked before about cortisol doing a couple other negative things in terms of thyroid hormone chemistry (affecting conversion and the pituitary).

But this one today is one in which cortisol levels are too high and suppress the receptors for T3. 

What symptoms would high cortisol dampening these receptors cause?

It would cause low thyroid symptoms like these:

• brain fog
• depression
• hair loss
• weight gain
• constipation
• dry skin, dry hair
• muscle pain
• infertility
• high cholesterol. 

If you have those symptoms and go to your doctor–and they order a TSH and T4–you might get diagnosed as hypothyroid and start taking medication like Synthroid^® or Armour^®….

But, if you have this cortisol problem, you won’t feel any better.

This happens all the time…

So, you could have all the medication you want floating around in your bloodstream.  But even if the hormone docks onto the receptors, nothing happens. Nothing “clicks.”

Another way of talking about this is to call this “resistance.”

See, there’s a receptor on the inside of the cell.  And when the hormone comes along and docks, it causes some changes inside the cell because messages go to the nucleus of the cell and DNA starts to produce different proteins.

High cortisol basically shuts down the message from traveling from the receptor into the nucleus of the cell.  

So, if you’ve got the type of scenario in which you were diagnosed hypothyroid but you’re taking medication AND the labs look normal BUT you still feel low thyroid– well, then this could be one of the reasons why.  


There’s another scenario in which you never got diagnosed hypothyroid in the first place  because your lab numbers look totally normal the whole time. 

This actually happens quite a bit. 

You still have those low thyroid symptoms we just talked about.  But your T4, TSH, T3, all that looks normal. 

Blood tests don’t look at receptors.  Blood tests can look at levels of T4, T3 etc.  They can look at levels of thyroxine-binding globulins.  They can look at Reverse T3.  But there’s no way for blood tests to look at what’s going on at the level of the receptors. 

So, finding this hidden cause is a process of elimination. 

What causes high cortisol? 

…The three big reasons are:

1. Inflammation
2. Stress
3. Diet

#1 – So, let’s start with inflammation…

Anything that inflames you can cause high cortisol throughout your body. Things like these:

• Food sensitivities (you probably don’t know you have)
• Leaky Gut
• Infections (parasites, viruses, bacteria)
• Dybiosis (bacterial/fungal/yeast imbalances & overgrowths in the small or large intestine)

…they can all cause you to have HIGH cortisol and suppressed thyroid hormone receptors and low thyroid symptoms. 

#2 – Psychological and emotional stress are a big source of high cortisol. 

Who doesn’t have stress?  The problem is if you have too much stress over the long term…or a super large single stressful event, like a divorce or a trauma…that causes you to secrete a lot of cortisol. 

That cortisol can flood the body…suppress the activity of the thyroid receptor…and you suffer low thyroid symptoms.  

#3- A bad diet can also create HIGH cortisol.  

Eating lots of refined sugars, stimulants (caffeine & artificial sweeteners) and simple carbs will cause high cotisol that will shut down those thyroid hormone receptors. 

High cortisol messing with your thyroid hormone receptors is a hidden cause–and it’s quite a ways down on our list because to find it, your doctor has to eliminate all other possibilities.  

To do THAT,  your doctor has got to be able to give your history a thorough review–not just spend 5 minutes without even looking you in the eye. Your doctor would need to be able to RECOGNIZE what you’ve already tried that didn’t work. 

Or realize that even though your lab tests are “normal”, you could legitimately still have  low thyroid symptoms. Your doctor needs to spend some time really thinking hard about your case.

Sadly, that’s two things  a lot of doctors don’t want to do: spend time and think. 

Based on the stories my patients tell me, there’s a LOT of doctors out there who would really like for you to just show up, pay, leave and the doc never have to talk to you. 

I’ve met doctors like that. 

And I’m beginning to think there’s more and more of them.  I think they all still want to help.  They just don’t want to exert a lot of effort. 

So, to get help you must find someone that understands this fact: there’s a lot of reasons why you can have low thyroid symptoms.  And then tries to work through the possibilities.

How? By AT LEAST asking for a  complete history to discover what you’ve already tried (meds, supplements etc) that has or has not worked.  

Next, obtaining the necessary lab tests to investigate the possibilities I’ve listed above. 

Your doctor has got some work to do.