Healthy Hormones

8 Common Causes of Thyroid Fatigue and How You Can Fix Them

Are you still fatigued even though you are taking your thyroid medication faithfully?


The fatigue found in thyroid disease can be because of many things.

Just taking your thyroid medication may not be enough to reverse these symptoms.

The many causes of thyroid fatigue include adrenal issues, autoimmune inflammation, food sensitivities, nutritional deficiencies, dietary issues, and even taking the wrong thyroid medication.

I will discuss each of these possible sources of fatigue and show you how to correct them.

Let's get started...


Causes of Thyroid Fatigue

Multiple things can influence your energy level.

Unfortunately, there usually isn't just one simple thing that you can do to reverse your fatigue.

It will require investigating all of the contributing factors and determining which of them may be playing a role in your particular situation.

Most doctors don't have the time in their busy office to dive into all of the possibilities.  Plus they may not even understand several of the causes or how to correct them.

That's why you need to become aware of the causes so that you can take more control of your own health and get yourself on the road to recovery.

1.  Adrenal Fatigue and Cortisol

The adrenal gland is your "stress" gland.  It produces the hormone cortisol.

Cortisol functions in the body by regulating blood sugar and metabolism, it activates the central nervous system, maintains blood pressure, and has anti-inflammatory actions.

Cortisol levels will go up during times of physical or emotional stress.  It speeds up metabolism so we are able to fight through that stressful time.

At first, people with elevated cortisol feel shaky, their heart may race, and they may have insomnia problems.

 Eventually the adrenal gland will not be able to produce enough cortisol to keep up with demand and the levels will drop and stay low.  This is called adrenal fatigue.

The thyroid and adrenal functions in the body are closely linked.

In fact, the TSH and cortisol levels tend to track together.

Even small changes in your cortisol level can cause significant symptoms, especially fatigue and brain fog.

Your symptoms will vary depending on how long you have been under stress.

To determine if you have an adrenal issue, I recommend either salivary cortisol testing or better yet, ordering a DUTCH test.

You can also also ask for a serum am cortisol level from your doctor.  This does not tell you as much information as a urinary cortisol level tested 4 times in a day, but it can still be helpful.

If your serum cortisol level is < 8, you most likely have an adrenal fatigue problem.

If it is >18, that also needs further investigation and treatment.

What to Do About It 

Stress management is essential for normal adrenal function.

This can include yoga, meditation, regular exercise, and scheduling time for hobbies and other things you enjoy.

It is also important to avoid stimulants such as caffeine and even ADHD medications.

Caffeine helps produce energy by putting pressure on your adrenal glands to produce more cortisol and increase adrenaline production.

That is not a good thing when the adrenal system is already weakened.

Therefore, try to wean off of your caffeine dependence if you have one.

Supplementation can also be extremely beneficial.

How to Supplement with Adrenal Support

Why I Like It

May boost energy and well being

Almost ALL hypothyroid patients have adrenal problems

May help boost immune function

Most patients experience improvement in 1-2 months

How to Tell if You Need

I don't always recommend testing for cortisol levels prior to treatment in every patient but if you do I recommend checking the following:

    • Serum Cortisol - AM cortisol should be between 14-16, anything less may be a problem (note: normal serum level doesn't rule out adrenal fatigue)

How to Use

    • 1-2 Tablets per day if using Glandulars (preferably taken in the am and at noon)
    • If using supplements designed to lower cortisol like phosphatidylserine then use it at night

My Recommended Brand and Product

Adrenal Glandulars (for more severe cases of adrenal fatigue.

Adrenal Adaptogens (for less severe cases of adrenal fatigue.

Phosphatidylserine (for cases of ELEVATED cortisol)

2.  Inflammation from Autoimmunity

Up to 90% of hypothyroidism is caused by Hashimoto's Thyroiditis.  Up to 10% of the population has Hashimoto's.  It is especially common in women (up to 20% of women may have it!).

Hashimoto's is an autoimmune condition.  This means that something has caused your immune system to go rogue and attack a part of yourself (in this case, the thyroid gland).

This attack results in inflammatory cells increasing in that part of the body. 

Inflammation causes you to feel "worn down," similar to how you feel when you are sick with a virus.

What to Do About It 

If you don't know if you have Hashimoto's, ask to be tested for it.

This is a blood test that checks for 2 antibodies:

  • TPO antibodies
  • Thyroglobulin antibodies

If either antibody level is >35, you have Hashimoto's Thyroiditis.

You should also talk to your doctor about any other autoimmune conditions that could be present.

It is also important to eat organic, natural food and avoid processed food and sugar.

Meal plans such as Whole 30, Paleo, and others are great for helping you stay on track and reducing the inflammation caused by the inflammatory food-like substances found in much of the standard American diet.

If you need more help, I would strongly recommend hiring a certified nutritionist to help you learn how to eat properly.

This will be discussed more below under blood sugar imbalances.

3.  Food Sensitivities

Thyroid disease is commonly associated with food sensitivities.

The most common of these is gluten.  Gluten is a protein found in grain products, especially wheat.

It is estimated that up to 1/3 of the population has some level of gluten sensitivity.

About 90% of all food sensitivities occur from the following foods:

  • Wheat
  • Milk
  • Soy
  • Eggs
  • Peanuts
  • Tree Nuts
  • Shellfish
  • Fish

These food sensitivities cause inflammation of the digestive tract which can impair its ability to absorb nutrients.  When you are deficient in nutrients, fatigue is typically a major symptom.

What to Do About It 

The gold standard for identifying food sensitivities is the elimination diet.

You can either remove one food at a time for 3 weeks, then reintroduce it and see if you react. This process could take 6 months or more to get through all of the foods.

Or, you can bite the bullet and remove all of the top 8 culprits together for 3 weeks, then reintroduce each one separately every few days.

If you react, keep that food out of your diet. If you don't react, you can continue to eat it then reintroduce the next one on the list.

There are also some reference labs that have IgG food sensitivity testing available.

I believe the data supports that ALL thyroid disease patients should be gluten-free and probably dairy-free, even if you don't react while eating an elimination diet.

I will discuss diet more under Blood Sugar Imbalances below.

4.  Low Ferritin/Iron

Ferritin is the storage form of iron.

Having optimal iron levels in the body is essential for normal energy production.  It also is required for normal thyroid hormone production.

A deficiency of iron causes fatigue and other symptoms such as hair loss, decreased exercise tolerance, frequent infections, and GI issues such as gas and bloating.

Hypothyroidism also affects the ability to properly absorb iron.  This creates a vicious cycle that results is severe fatigue.

Even when there is no evidence of anemia (low hemoglobin), supplementing with iron has been show to  improve energy and reduce fatigue.

What to Do About It 

Ask your doctor for a complete iron study.

This will include a serum ferritin, total iron, and TIBC.

If your levels are suboptimal or if you continue to have symptoms of low iron, consider supplementing.

How to Supplement with Iron

Why I Like It

May boost energy levels

Up to 50% of Hypothyroid patients are deficient in iron

Helps promote thyroid conversion & function

Generally works within 1-2 months

How to Tell if You Need It

Check your iron studies and only supplement if your levels are sub optimal or low:

  • Ferritin - Optimal Levels = 40-50
  • Serum Iron - Middle of the reference range
  • TIBC (Total Iron Binding Capacity) - Middle of the reference range
  • Percent Saturation - 35-38%

How to Use

  • Liquid Iron:  start with 10 ml each day, do not exceed 20 ml per day (if you take more than 1 dose per day make sure to split it apart from one another and take at least 4 hours away from your thyroid medication)
  • Iron Capsules:  start with 1 capsule of iron and increase up to 3 per day as tolerated and based on your serum iron/ferritin levels (take at least 4 hours away from your thyroid medication)

My Recommended Brand and Product

Use liquid iron if you have intestinal issues such as gas, bloating, diarrhea, constipation or if you have previously failed capsule forms of iron:

Use this capsule form if you don't tolerate the liquid iron version above (some patients have various symptoms on liquid iron such as teeth pain or simply can't tolerate the taste or texture of the liquid):

5.  B12 Deficiency

Thyroid disease is commonly associated with low stomach acid levels.  If you don't have adequate stomach acid, you can't fully digest your food and extract the nutrients from it.

Inflammation from autoimmunity such as Hashimoto's only makes the absorption of the nutrients worse.

Lack of thyroid hormone causes nutrient deficiencies in certain vitamins such as B12.

In fact, up to 40% of hypothyroid patients have suboptimal levels of vitamin B12.

B12 is directly involved in energy production due to its effects on mitochondria in the cells.

A deficiency of B12 will decrease the efficiency of the mitochondrial energy production, which will result in fatigue.

If the deficiency is severe, it can also cause a type of anemia called pernicious anemia.


Up to 60% of the population has some form of this gene mutation.

MTHFR (methyltetrahydrofolatereductase) is an enzyme that adds a methyl group to certain nutrients which allows our body to metabolize them.  When that enzyme is deficient, we cannot metabolize nutrients as efficiently which can result in a deficiency of that nutrient.

The B vitamins such as B12 and folate are metabolized in this way.  Their levels can be suboptimal in a patient with an MTHFR mutation.

It can also cause an elevation in homocysteine levels, which increases the risk for cardiovascular disease.

Read more about MTHFR by clicking here.

What to Do About It 

You should ask your doctor to be tested for the following:

  • Serum B12 - should be > 1000
  • MCV (mean corpuscular volume) - part of a Complete Blood Count - should be >92
  • Homocysteine - should be < 9
  • MTHFR - if heterozygous or homozygous for either mutation, you will need to take a methylated B vitamin supplement.

If any of the results are abnormal, consider supplementation. 

Supplementing with a B complex in addition to vitamin B12 shots can dramatically improve energy levels.

Make sure to find a B complex with high levels of B6 like this one.

You should also consider supplementing with B12 shots.

Why not oral or sublingual?

Shots are superior to oral forms because they get directly into the tissues and bypass gastrointestinal absorption.

Many thyroid patients have issues with constipation, SIBO, and other GI related issues that can impair absorption of nutrients.

Completely bypassing the GI tract can help ensure that the B12 is absorbed as much as possible.

B12 shots are one of the best ways of increasing energy levels in hypothyroid patients.

Remember - It is important to make sure your B complex and your B12 shots are methylated unless you know that you don't have the MTHFR mutation.

How to Supplement with B12 Shots

Why I Like It

May boost energy and reduce fatigue

May help increase metabolism and fat loss

Help improve mood and increase concentration

Generally works within 1-2 weeks

How to Tell if You Need It

Patients with the following symptoms should consider using B12 shots:

    • Obesity or weight gain
    • Fatigue or low energy levels
    • Lack of sleep or insomnia
    • Depression or anxiety
    • Hair loss or lack of hair growth
    • Serum B12 levels < 1000
    • Homocysteine levels > 9
    • MCV (mean corpuscular volume) > 92
    • High levels of inflammation

How to Use

    • Take 5,000 mcg of Methylcobalamin every 7 days for at least 10 weeks
    • You will need 10 weeks worth of injections to saturate tissues and increase cellular B12 levels

My Recommended Brand and Product

Make sure you get methylcobalamin shots in a high enough dosage (5000 mcg) for best results.

6.  Blood Sugar Imbalances

The standard American diet is loaded with processed foods, sugar, and simple carbs.

Sugar and simple carbs provide a quick energy boost because they are rapidly absorbed and metabolized, but they are harmful in the long run.

When you eat sugar or simple carbs, your glucose level surges.  That triggers your pancreas to release insulin which transports the glucose into the cells.

The insulin then drives down your sugar.  Sometimes your body overcorrects and your glucose levels drop too low.

This causes symptoms such as fatigue, shakiness, brain fog, and the desire to eat more sweets or carbs.

You therefore eat more sweets or carbs, and the cycle starts all over again.

The higher levels of insulin also results in long term weight gain and/or difficulty losing weight.

If you find yourself feeling tired around late morning and mid afternoon, your blood sugar is probably on such a roller coaster.

What to Do About It 

The body can produce energy by using 2 substances for energy:  sugar or fat.

Since most people eat way more sugar and carbs than they should, their bodies use sugar as the default energy source.

In order to get off of the sugar/carb roller coaster, you will need to "train" your body to use fats preferencially over sugar.

The best way to do this is to cut sugar and simple carbs completely out of your diet.

Yes, you can do it!

It typically takes 3-4 weeks to convert your body into a fat-burning machine.

You might feel a little woozy and tired the first few days, but those symptoms will go away. 

You will then notice a increase in energy and a drop in your appetite.  Plus, you will most likely drop several pounds.

There are several excellent diet plans on the market that can help you make this lifestyle change (I don't like the word diet, which sounds temporary).

My favorite dietary programs include:

7.  Poor Sleep Hygiene

Low (or high) thyroid hormone may directly reduce the QUALITY of your sleep.

It has been shown that thyroid hormone is involved in both REM and non REM sleep.

This may explain why some patients can still have fatigue despite sleeping 10 or more hours per night.

It doesn't matter how long you sleep if the quality of that sleep is poor.

If hypothyroidism is causing a reduction in your quality then you will need thyroid hormone replacement to fix this problem.

If you aren't sleeping well as a result of high stress, anxiety or reliance upon caffeine then you really need to step it up and focus on getting more sleep.

Another important factor is to consider WHEN you are getting your sleep.

People tend to have better functioning circadian rhythm's when they sleep through the EVENING, and not through the daytime.

In fact, studies show that people who work nights have an increased risk of DEATH from all causes and an increase risk of heart attacks.

What to Do About It 

Get at least 8 hours of sleep per night.

Your bed should be reserved for sleep and sexual activity ONLY.  Avoid TV, reading, computer work, or playing on your smart phone while in bed.

Try to go to bed at the same time every night and get up at the same time every morning.

We are creatures of habit.  Our body will respond better to a consistent routine.

Avoid any stimulants in the evening.  They will affect your sleep pattern.

Obstructive sleep apnea is also a common cause of sleep issues.  You should consider seeing your doctor to have it ruled out if nothing has worked to this point.

If sleep apnea has been ruled out and you are still not sleeping or sleeping well, it may be time to consider supplements.

How to Supplement to Improve Your Sleep

Why I Like It

May help improve energy levels

May help to decrease levels of inflammation

May help reduce brain fog and mental slowness

Requires lifestyle change for best results

How to Tell if You Need It

    • You should be getting 8 hours of quality sleep every night.
    • If you find yourself waking up exhausted then you should consider checking for sleep apnea or a trial of the following supplements to improve sleep

How to Use

    • Take each supplement as indicated on the bottle or as recommended below
    • In addition to these supplements make sure you practice adequate sleep hygiene, that means: black out curtains for your bedroom, noise cancelling ear plugs, having a consistent sleep schedule, and avoiding all electronics 3 hours prior to your scheduled bed time

My Recommended Brand and Product

For minor sleep issues start with supplements containing 5-HTP which may promote proper melatonin production and induce sleep naturally (take 100mg 30 minutes before your scheduled bed time):

For more difficult cases consider the addition of melatonin + 5-HTP, start with 1-3mg of melatonin and don't be afraid to use melatonin if you need it.

For more the most difficult cases consider using serotonin and GABA potentiators. These supplements help enhance GABA and serotonin neurotransmitters in the brain and help induce deep sleep.

8.  Are You On The Right Thyroid Medication?

It's important to end this article by discussing your thyroid medication.

Most physicians are trained to manage thyroid disease by monitoring the TSH level.  "Normalizing" the TSH is typically the only treatment that is done.

However, even when the TSH is "normal," studies show that patients may have 20-30% less circulating T3 and T4 levels compared to age-matched controls.

The most sensitive marker to determine cellular levels of thyroid hormone is the reverse T3:free T3 ratio.

That's why it's important have a complete thyroid panel drawn, not just a TSH.

By far the most common medication used by physicians when treating hypothyroidism is a T4 only medication like levothyroxine or Synthroid.

If you're body isn't converting T4 to T3 like it should, then adding a T4 only medication will not be enough to increase your cellular thyroid hormone levels.

If your cellular thyroid levels are low, fatigue will be a predominant symptom.

What to Do About It 

Ask your provider to order a complete thyroid panel which includes:

If your reverse T3:free T3 ratio is < 0.2, ask your provider about changing to a natural dessicated thyroid (NDT) medication such as Armour Thyroid, WP Thyroid, or Nature-throid.

These medications consist of about 20% T3 and 80% T4.

Adding T3 only medication such as Cytomel to your levothyroxine is also an option.

I discuss thyroid medications in much more detail in my article found here.

If your doctor is unwilling to do this, you may need to find a different doctor that is willing to work with you.  A doctor who specializes in functional medicine would be preferred.


Fatigue is a very common symptom of thyroid disease and may indicate a deeper problem ranging from hormone imbalances to nutrient deficiencies.

Simply replacing thyroid hormone may not be enough to completely energize your body and reduce your fatigue.

It is important to take a comprehensive approach to the problem and investigate all potential contributing factors.

The combination of these therapies above has proven to be very effective in my patients and I believe they can help you as well.

Make sure to employ ALL of the therapies that are relevant to you and your situation.

Now it's your turn:

Are you suffering from thyroid fatigue?

What have you tried?

Leave your comments below!

About the Author Dr. Jeff Whelchel

Dr. Whelchel is a family physician who specializes in functional medicine, especially hormone optimization. He has over 20 years experience in private practice managing patients with various medical issues. His passion is helping patients reach their full potential of wellness and quality of life. He grew up in the Texas Panhandle where he currently lives. He is married and has 3 awesome children.

Leave a Comment:

Kelly Irons says September 5, 2017

Good article

    Dr. Jeff Whelchel says September 5, 2017

    Thank you Kelly. I hope you are doing well.

Tonya MacDonald says September 6, 2017

Dr. Whelchel, Thanks for sharing your amazing article! God bless you. Your patient, Tonya MacDonald

    Dr. Jeff Whelchel says September 6, 2017

    Thank you Tonya.

Jade says September 6, 2017

I have been needing an injection for B12. I do not have insurance. How can I get it and How much? I will also be calling to make an appointment with you to discuss our options because my T3 levels are low.

    Dr. Jeff Whelchel says September 6, 2017

    Hi Jade. Come see me and we can discuss the T3 plus the B12 shots.

Robyn says September 6, 2017

Dr. Whelchel, I wanted to tell you that Brittany introduced me to the Ketogenic diet. It has made a huge difference for me emotionally and physically. I’m down about 20 lbs since I saw you last. Mom has also started this and has lost 9 lbs in 10 days. I don’t necessarily like to call it a diet. It’s more like a new way of eating. After about a week of eating this way, I knew I never wanted to go back to the way I ate before. Just wanted to put this out there for anyone thinking of possibility trying the Keto diet. Thank you for all you’ve done for me and my family.

Debbie Barron says September 7, 2017

Great article! Currently Dr.Larance McAfee’s patient, but because of insurance change, I may need a new primary care physician. Are you taking new patients?

    Dr. Jeff Whelchel says September 7, 2017

    Hi Debbie. I’m not currently accepting new patients. However, I will be starting an online hormone practice very soon. Stay tuned!

Janie says September 7, 2017

Doc this is great maybe we need to do blood work haven’t done it in a while

Sarah Battle says September 14, 2017

Thanks for the info! Based on this, I need to add B and iron (duh!) I don’t want to take synthetic ANYTHING. I have a good B vitamin product through my wholesale account with Young Living. I see that ferrous gluconate is not synthetic. Are any of the other ingredients in the Floradix synthetic? Are the ingredients in Opti-Ferin-C synthetic?
A friend recommended this iron supp that you might consider: Gaia Herbs Plant Force Liquid Iron
Thanks again! So glad you are a Functional practitioner!

Rene' Schultz says September 20, 2017

Great article! Informative and easy to understand. I’ve been studying and reading about hypothyroidism, adrenal fatigue, and Hashimoto’s. With your articles and guidance I think I may be able to get my dr to get onboard.
Rene’ Loyless Schultz

    Dr. Jeff Whelchel says September 20, 2017

    Thank you, Rene’. I hope it helps! Take care.

Best B12 Shots says August 19, 2018

Great to see your blog. Awesome information you shared. Looking forward to more great content.

debra fountain says April 1, 2019

my cortisol was just tested and morning cortisol was 32.8, of course all hormones are all over the place. My ferritin is 224 , I have been on Armour about 2 1/2 months. I have had alot of labs done , but Dr just says come back in a month

    Dr. Jeff Whelchel says May 11, 2019

    Hi Debra. That is a very high morning cortisol level. I would insist on speaking to the doctor about it or scheduling with another doctor that is comfortable assessing adrenal function.

Michael Levine says May 25, 2020

Do you know of any physicians in Jacksonville, FL who specialize in functional medicine?

    Dr. Jeff Whelchel says November 11, 2020

    Go to and click on “Find a Provider.” Best of luck.

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