The Connection Between Chronic Fatigue Syndrome and Low T3

Chronic Fatigue Syndrome and Low T3 (The Connection)

When Traditional Thyroid Testing and Treatment Fails

Did you know that some people who have chronic fatigue syndrome have some very interesting thyroid lab tests?

These lab tests may shed light on what is happening to cause chronic fatigue syndrome, at least in some individuals. 

Why is this important?

Because the thyroid lab findings in these patients are not the “typical” way that thyroid disease presents. 

In addition, it may be that the thyroid dysfunction found in these patients is a potential treatment option and one way to actually treat and manage chronic fatigue syndrome. 

To highlight these facts I am going to be pulling information from a new clinical study (done in 2018) which highlights the connection between chronic fatigue syndrome and low T3

I will be using this study to help elaborate (1) on what could be causing chronic fatigue syndrome or CFS for certain individuals. 

I’ve long held the view that certain cases of hypothyroidism can actually result in a chronic fatigue-like syndrome as well as a fibromyalgia-like syndrome

And the key here isn’t that the low thyroid state results in these syndromes but more so that these syndromes can be TREATED and MANAGED with the right thyroid​​ medication.

So if you are someone who has chronic fatigue syndrome then this article is for you!

You may also find this article helpful if you have the symptoms of chronic fatigue syndrome AND known (or suspected) low thyroid function. 

Let’s dive in…


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Thyroid Causes Fatigue & Low Energy

The first thing you should know is that low thyroid function causes fatigue

But the fatigue caused by hypothyroidism is typically not sufficient enough to be labeled chronic fatigue syndrome.

Chronic fatigue syndrome is typically much worse, doesn’t really improve with most therapies, and renders people who have it unable to perform even daily tasks. 

The fatigue associated with hypothyroidism tends to be moderate in that it still impacts your daily life but you can still function. 

But, like anything, the fatigue associated with hypothyroidism exists on a spectrum. 

And on this spectrum, there will always be people who are hit harder than others. 

In fact, there are many people with hypothyroidism who have mild fatigue but other symptoms on the extreme end. 

On the flip side, there are also people who present PRIMARILY with fatigue and other mild symptoms. 

It is these people that I want to focus on. 

There seems to be some subgroup of thyroid patients who get harder on the fatigue spectrum than others. 

And these people can often present with symptoms that match those found in chronic fatigue syndrome. 

Does this mean that they have chronic fatigue syndrome and not hypothyroidism?

I don’t think so. 

It’s much more likely that they have chronic fatigue syndrome caused BY hypothyroidism. 

A Hidden Cause of Chronic Fatigue Syndrome?

Chronic fatigue syndrome is known to be a very difficult-to-treat condition, as pretty much anyone with the disease will tell you. 

The problem with managing chronic fatigue syndrome is that no one really knows what causes it. 

In fact, multiple different causes (2) have been identified but there isn’t necessarily a unifying factor among these various causes. 

The study we are evaluating today took into account the multiple causes of chronic fatigue syndrome and tested around 100 patients for the following:

  • Thyroid function
  • Inflammation
  • Gut wall integrity
  • Nutrient status

They found that of about 100 chronic fatigue syndrome patients, most of these patients had similar thyroid lab studies. 

While almost all of these patients had abnormal thyroid lab tests (low thyroid function or hypothyroidism) they found a correlation between those with inflammation and low T3. 

This information suggests that certain individuals with chronic fatigue syndrome experience a set of thyroid lab tests in line with a condition known as non-thyroidal illness syndrome or NTIS

I’ve talked about the connection between NTIS and other conditions such as mold exposure in articles such as this

But what you need to know here is that most doctors consider this abnormal thyroid lab pattern to be normal. 

The problem with this logic is that many patients who have NTIS lab patterns actually improve with thyroid hormone replacement!

They do not, however, improve on conventional thyroid hormone replacement medications such as levothyroxine and Synthroid

Instead, they often need to use T3 thyroid hormone medications such as Cytomel or liothyronine

And these medications are just not commonly prescribed. 

This leaves many patients suffering from chronic fatigue syndrome secondary to thyroid conditions, never getting appropriate treatment. 

Thus the reason for this article! To explain the connection and talk about new treatments for this condition. 

The Low T3 Connection

What’s the connection between chronic fatigue syndrome and thyroid function?

It has to do with a few important findings. 

The first is that those people who have low-grade chronic inflammation tend to experience thyroid dysfunction. 

But the dysfunction that they experience is NOT typical of standard hypothyroidism. 

Most people who have hypothyroidism or low thyroid function present with a high TSH and normal to low free thyroid hormone levels (these aren’t often tested by doctors but if you do get them tested you would find that they are low or normal). 

But people who have chronic fatigue syndrome, according to this study, didn’t have a high TSH but exhibited a different set of thyroid lab abnormalities. 

These patients were found to have LOW T3 and HIGH reverse T3. 

If you know a little bit about thyroid function, or if you’ve been reading my blog, you know that these lab tests are probably the two most important thyroid lab tests to look at. 

But, unfortunately, they are hardly ever ordered by most doctors!

The researchers in this study speculated that the thyroid plays an important role in regulating energy levels by virtue of its impact on cellular tissues. 

What you need to understand is that your thyroid drives energy production in your cells. 

If you don’t have enough T3 thyroid hormone to interact with your cells you may enter what is known as a hypometabolic state (3). 

A hypometabolic state is just a state of low energy production, depressed metabolic function, and decreased mitochondrial energy production. 

The net result is a decrease in total energy production and, therefore, fatigue. 

Pretty straightforward as long as you lose all of the medical jargon! 

It’s important to note that not EVERY patient with chronic fatigue syndrome had these abnormal thyroid lab tests. 

In fact, only about 16 of the 100 or so patients had them. 

The patients who had low T3 levels were also the ones who had high levels of inflammation as tested by hs-CRP which is a test used to evaluate for inflammation. 

So we can conclude that high levels of inflammation in certain patients result in low thyroid function, low t3 levels, and high reverse T3 levels. 

And these patients represent only a subgroup of ALL chronic fatigue syndrome patients. 

This is why I stated earlier that certain people exhibit a chronic fatigue-like syndrome and perhaps not a true chronic fatigue syndrome. 

I personally believe that many patients diagnosed with chronic fatigue syndrome actually have low thyroid function masquerading as chronic fatigue syndrome. 

But the key here is that these patients CAN be treated and their fatigue CAN resolve… at least with the right treatment. 

Treating CFS with T3 Thyroid Medication

The study we are evaluating today didn’t actually go into treating chronic fatigue syndrome due to thyroid dysfunction but I still think it’s important to touch on. 

The study merely showed that there seems to be a connection between low T3, chronic fatigue syndrome, and inflammation in people who have chronic fatigue syndrome. 

This can be easily explained. 

But what isn’t explained is how to actually treat the problem. 

And here is where I am going to draw from my own personal experience treating patients with chronic fatigue syndrome using T3 thyroid hormone. 

So here’s one big problem with hypothyroidism and why many people who take thyroid hormones don’t often feel better:

It has to do with the fact that they are taking the wrong thyroid medication. 

The most commonly prescribed thyroid medications (levothyroxine and Synthroid) only contain T4 thyroid hormone. 

But we know from studies like this one, and MANY others by the way, that it’s possible to take Synthroid and levothyroxine and not convert it to T3 (the active thyroid hormone). 

This occurs due to problems with thyroid conversion. 

Here’s where things get interesting…

You can take all of the levothyroxine and Synthroid that you want (even to the point that it suppresses the TSH) but if your body isn’t converting it to T3 then you simply won’t feel better. 

And this problem is occurring more than people probably realize. 

One of the most common inhibitors of T4 to T3 conversion is inflammation. 

This makes perfect sense as the researchers in this study found that those people who have high levels of hs-CRP (a marker of inflammation) had LOW levels of T3 and high levels of reverse T3. 

This is the exact lab pattern we would expect if someone wasn’t converting T4 into T3. 

Instead of taking that T4 and converting it to T3, we would see a buildup of T4, a reduction in free T3, and an elevation in reverse T3. 

So it really doesn’t matter how much T4 you are taking if your body isn’t converting it. 

This is where T3 thyroid medications such as Cytomel and liothyronine come into play. 

These medications provide your body DIRECTLY with T3 thyroid hormone and bypass the need for thyroid conversion and the need for T4. 

And, in my experience, this is exactly what patients with chronic fatigue syndrome need. 

They tend to benefit greatly by providing the body with that T3 which results in immediate energy production at the cellular level

Final Thoughts

Why does this matter to you? 

It’s important for you to understand that chronic fatigue syndrome can be caused by MULTIPLE different conditions and problems. 

But one of those problems may be related to your thyroid function. 

And if it is related to your thyroid function then it CAN be treated. 

But you may never know if this is the case unless you get tested properly. 

And most doctors are not likely to start ordering the tests which are necessary to figure it out. 

If you have chronic fatigue syndrome (known or suspected) then it would be a great idea for you to ask your doctor to order a complete thyroid lab panel which includes the following:

If you can get these tests ordered then you can figure out if your chronic fatigue syndrome is actually low thyroid function. 

If this is the case then you CAN get treatment and most likely completely recover. 

My experience suggests that most people with chronic fatigue syndrome (provided it’s due to low thyroid function) will see significant improvement with the use of T3 thyroid hormone. 

In fact, most people with chronic fatigue syndrome in general still benefit at least a little bit from the use of T3 thyroid hormone. 

This thyroid hormone gets directly into your cells, bypasses thyroid conversion, and turns on your cells to produce more energy and ATP. 

Also, don’t be afraid to print out this study and bring it with you to your next doctor’s appointment! 

Doctors tend to respond well to medical research and this research is still very new (this study was done in 2018). 

But now I want to hear from you:

Do you have chronic fatigue syndrome?

Do you ALSO have thyroid dysfunction or hypothyroidism?

Have you had your free T3 levels or reverse T3 levels tested?

If so, what were your results?

Leave your questions or comments below!




chronic fatigue syndrome and your thyroid

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About Dr. Westin Childs

Hey! I'm Westin Childs D.O. (former Osteopathic Physician). I don't practice medicine anymore and instead specialize in helping people like YOU who have thyroid problems, hormone imbalances, and weight loss resistance. I love to write and share what I've learned over the years. I also happen to formulate the best supplements on the market (well, at least in my opinion!) and I'm proud to say that over 80,000+ people have used them over the last 7 years. You can read more about my own personal health journey and why I am so passionate about what I do.

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