Do you have any of the following symptoms:
A strong urge to sleep?
These are common symptoms of hypothyroidism. But what if your blood work always comes back in normal ranges?
What’s going on?
Could you still have hypothyroidism (even when your lab tests are normal)?
Odds are, it has more to do with incomplete data. You see, the test(s) your doctor runs does not tell the whole story about your thyroid. In reality, it’s just a tiny piece of the puzzle. You could have a condition known as subclinical hypothyroidism or euthyroid sick syndrome. Both of which are common causes of fatigue – even when your thyroid lab tests are normal.
Your thyroid gland & fatigue
If your thyroid gland is not functioning at optimal levels, you’re going to experience fatigue. It’s as simple as that. And the prevalence of diminished thyroid function in developed countries is on the rise.
In community surveys, the prevalence of clinical hypothyroidism varies from 0.1 to 2 percent. (1) In Canada, that’s almost 800,000 people with hypothyroidism. In the United States, that’s up to over six million people diagnosed with hypothyroidism.
The prevalence of subclinical hypothyroidism is even higher. The presence of subclinical hypothyroidism is anywhere from 4 to 10 percent of adults. (2) That’s up to 3.7 million Canadians with subclinical hypothyroidism. And up to thirty-two million Americans with a low-functioning thyroid gland – even though their doctor(s) say otherwise.
To clarify, subclinical hypothyroidism is a condition where you may have many of the symptoms commonly associated with low thyroid (like fatigue!) but your TSH lab value still falls into normal the range. This often occurs in a condition called Hashimoto’s thyroiditis. Hashimoto’s is the autoimmune form of low thyroid. It is thought that up to 80% of low thyroid cases are actually Hashimoto’s. (3)
Normal thyroid labs & fatigue
When your doctor tests your thyroid function, he/she will perform a test called TSH. TSH stands for thyroid stimulating hormone. TSH signals to your thyroid gland to release thyroid hormone.
TSH is what’s known as an inverse marker. If your thyroid function is low, you’ll have elevated TSH levels. If your thyroid function is in excess (hyperthyroid), you’ll have low levels of TSH. Unfortunately, if your TSH comes back within “normal” ranges, your doctor will tell you that your thyroid function is fine. And that’s where the investigation stops.
What is a normal TSH reading?
In conventional medicine, a TSH reading of 0.2mIU/L – 4.0 mIU/L is normal. (4) The normal range is developed by screening large numbers of people within a particular population. But as I referenced earlier, the prevalence of hypothyroidism is on the rise. With more people testing positive for low thyroid function, what’s “normal” starts to shift upwards.
Imagine if everyone in a country had hypothyroidism. Then hypothyroidism would be “normal”. Normal does not equate to healthy. To get a better idea of what a healthy (not normal) TSH reading looks like, you need to look to functional medicine.
Functional medicine looks at healthy members of a population (in this case, those without hypothyroidism) and determines the reference range based on what is ideal, not normal. The functional reference range for TSH is 0.5 mIU/L – 2.0 mIU/L. Notice how the upper end of the functional reference range is half that of the conventional range.
If your TSH reading is above 2.0 mIU/L, your thyroid is under-functioning. Meaning your thyroid gland could be the root cause of your fatigue. (5)
But what if your TSH is within the functional reference range, does that mean your thyroid is healthy?
Thyroid antibodies and fatigue
Testing TSH alone is not enough to determine the health (or lack thereof) of your thyroid gland. Nor is testing TSH, T3, and T4. In order to properly asses thyroid function, you need to look at something called thyroid antibodies.
Antibodies are small proteins made by your immune system. They are used to kill/neutralize foreign invaders like bacteria and viruses. But sometimes your immune system gets confused. Sometimes it creates antibodies to its own tissue(s). Thyroid antibodies are created when your immune system thinks part of your thyroid gland is an invading bacteria or virus!
Did you know: more than 80% of hypothyroidism is caused by an autoimmune condition.
Autoimmune hypothyroidism is known as Hashimoto’s disease. It occurs when your immune system attacks your thyroid hormone – causing low levels of T3 and T4, and elevated levels of TSH (remember, TSH is an inverse marker).
What’s most important about thyroid antibodies is that they appear in your bloodwork years before your TSH, T3, or T4 goes out of range. In fact, antibodies can be prevalent in your blood up to ten years before your TSH goes out of range. (6) And if your antibodies are out of range, fatigue and all the other hypothyroid symptoms could start to manifest – even if your TSH is within normal ranges.
What is the normal range for thyroid antibodies?
You can produce two different antibodies to your thyroid gland. One is called thyroid peroxidase antibodies (anti-TPO). The other is called thyroglobulin antibodies (TG antibodies). It is completely healthy to have a few antibodies in your blood. This becomes problematic when your antibodies rise too high. The ideal ranges for thyroid antibodies are:
- Thyroid peroxidase antibodies (TPO) = 0 – 34 IU/mL
- Thyroglobulin antibodies (TG) = 0–0.9 IU/mL
Common thyroid conditions that are hidden causes of fatigue
Ok, now you know some of the basics regarding your thyroid health. Now, I’m going to show you a couple of thyroid conditions that could be the hidden cause of your fatigue.
- Subclinical hypothyroidism
- Euthyroid sick syndrome
Subclinical hypothyroidism and fatigue
Subclinical hypothyroidism is diagnosed when your TSH (thyroid stimulating hormone) is elevated but your T3 and T4 thyroid hormones are within normal ranges. In conventional care settings, you’ll often be told to exercise a little more and eat healthily. But you will rarely be treated.
This lack of treatment occurs even if you’re symptomatic. If you’re fatigued, depressed, anxious, gaining weight, and/or constipated, you’ll often be told there’s nothing that can be done until your T3 or T4 values go out of range.
Those of you with subclinical hypothyroidism can find it incredibly challenging to get help from your medical doctor. All too often, conventional medicine plays a wait and see approach. Meaning, come back in six to twelve months and if your T3 or T4 levels are out of range at that time, then I’ll treat you.
That sounds crazy, doesn’t it?
Why would you wait to treat a condition that in all likelihood is going to develop?
It makes sense to start treatment now – before you go on to develop clinical hypothyroidism. Especially if you are symptomatic. To do this, I recommend finding and working with a knowledgeable functional medicine practitioner. There, you can determine if your thyroid condition is caused by an autoimmune response inside your body (it probably is). And get to work on increasing your energy right away!
Euthyroid sick syndrome and fatigue
Euthyroid sick syndrome is another hidden cause of fatigue. Euthyroid sick syndrome is diagnosed when your TSH is within normal range but you have elevated thyroid peroxidase antibodies and/or thyroglobulin antibodies.
Since conventional thyroid testing rarely involves thyroid antibody tests, euththyroid sick syndrome is rarely diagnosed in a conventional setting. This is incredibly unfortunate as you now know that up to 80% of hypothyroidism is caused by Hashimoto’s disease.
Remember, Hashimoto’s disease is an autoimmune condition. You can have elevated antibodies (TPO and/or TG) up to ten years before your TSH goes out of range.
Even if your TSH is within normal ranges, you can still experience all the symptoms of hypothyroidism (like fatigue) just with elevated antibodies. This is euthyroid sick syndrome. And if you want to overcome fatigue, it needs to be treated.
I recommend working with a knowledgeable functional medicine practitioner who can help you identify the underlying trigger for your autoimmune reaction. Often, it’s due to the food you eat. You can start your journey towards increased energy by performing the fatigue reset diet. It’s the perfect starting place for conditions like euthryoid sick syndrome.
Proper thyroid testing when dealing with fatigue
In order to properly diagnose your thyroid function, you need to be aware of two principles:
- Conventional versus functional lab ranges.
- Always compare your lab values to the functional reference range.
- Functional reference ranges are based on health. While conventional ranges are based on disease.
- A TSH value of 3.99 mIU/L is still within the conventional range. Meaning it’s unlikely your doctor will treat you. Even though you’re bound to feel fatigued.
- The overwhelming majority of hypothyroidism is caused by an autoimmune attack on your thyroid.
- Therefore, in order to get a complete picture of your thyroid health, you need to run both thyroid peroxidase and thyroglobulin antibodies.
To gather a big picture view of your thyroid health, I recommend running the following tests:
- Free T3
- Free T4
- Total T3
- Total T4
- Reverse T3
- Thyroid peroxidase antibodies
- Thyroglobulin antibodies
This is far more comprehensive than just TSH. Unfortunately, many state-funded healthcare systems do not have the resources to run this thorough of a thyroid panel. This is why TSH is usually the only lab run.
In order to get a comprehensive view of your thyroid, you may need to look to private laboratory testing. If you’re dealing with chronic fatigue syndrome or any other unknown cause of fatigue, proper thyroid testing is absolutely essential.
Now, I want to hear from you!
How has your thyroid health affected your energy levels? Reply in the comments section below!
Want to know more than your doctor about fatigue? Check out all our writings on how to obtain a fatigue-free body!
Also published on Medium.