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The Causes Behind Poor Thyroid Conversion and Low T3 Levels

Today’s article will review why you develop Low T3 and what you can do to increase your levels of T3 levels naturally. It’s no surprise that the majority of people with thyroid disease suffer with ongoing thyroid symptoms and ongoing visits to the doctor or endocrinologist. Much of this has do with a thyroid conversion problems leading to low T3.

If one month your thyroid levels are up then the next month your thyroid levels are down, you are probably suffering with some kind of T4-3 conversion issue resulting in Low T3.  If the conversion of T4 to T3 is poor, then you will experience many of the common hypothyroid symptoms.

Symptoms of Low T3

  • Fatigue,
  • Depression
  • Sensitivity to cold temperatures,
  • Brain Fog (difficulty concentrating/Focusing)
  • Weight gain.
  • Hair Loss

Keep in mind, that this poor conversion of T4 into T3 can occur even if your TSH levels appear to be normal and in range.

How is it possible to have thyroid problems with normal labs?

Transcript of video

Dr. Hagmeyer clinic director at explains How Poor Thyroid Conversion or Low T3 is overlooked by many practitioners who only look at TSH and T4 blood tests.

This pattern of Hypothyroidism often shows up with “Normal” Thyroid Labs With Symptoms of Hypothyroidism – The Thyroid Under conversion Problem

90% of women taking thyroid hormones will fail to feel normal

Understanding T4-T3 Conversion and Low T3

Let me explain. There is two forms of thyroid hormone. Thyroxine, commonly called T4, and triiodothyronine, commonly called T3. T4 is the inactive form of thyroid hormone, meaning it does not have the ability to bind to cells and create a metabolic response. T3 is the active form of thyroid hormone, responsible for binding to cells and creating metabolic responses including weight loss.

Your thyroid gland produces predominantly inactive T4. This means that the body must convert T4 to T3, in order to have normal thyroid responses. This conversion takes place primarily in the liver and by the bacteria living in the gut mucosa.

Low T3 Symptoms and Causes


So What Does This Have to do With Thyroid Symptoms and “Normal” looking labs?

The negative feedback loop between the thyroid and the pituitary gland is with TSH and inactive T4. When T4 levels drop then TSH is elevated to tell the thyroid to produce more hormone. If T4 is elevated then TSH is suppressed. It works both ways.

So if T4 and TSH look normal on the lab panels, the true problem may never be investigated and the person may go on suffering indefinitely.

When there is under conversion of T4 to T3, we can’t have a normal thyroid responses. T4 does us no good if we can’t get it into an active form.

This thyroid under conversion issue is one of the many reasons why patients with hypothyroid symptoms go un diagnosed and mismanaged.

So What Causes T4-3 Thyroid Underconversion?

When our thyroid gland produces thyroid hormone, it is produced in the form of T4 which is not a very strong form of thyroid hormone. In order for the thyroid hormone to properly do its job, we have to convert the T4 into a more active form called T3.

Much of the conversion occurs in the liver. If the liver is not working well due to toxicity, insulin resistance, inflammation or some other liver disorder, then the conversion will not occur correctly. I have done a two part video series on the importance of liver function and thyroid disease here

Thyroid conversion is also carried out in the digestive tract. Gut Dysbiosis and other issues causing poor digestion can lead to poor thyroid conversion. Problems with cortisol caused by adrenal fatigue and chronic stress is another possible culprit when it comes to the poor conversion of T4- into T3 conversion.  Cortisol is crucial for the conversion of T4 thyroid hormone into the active T3.

Conversion issues also include the conversion of T4 into an inactive hormone called Reverse T3 (rT3).

Although reverse T3 is inactive, it does have the ability to block active T3 by binding to receptors that are designed for T3.

The Causes Behind Poor Thyroid Conversion and Low T3 Levels

Other Factors Affecting The Conversion of T4- T3 Which Must Be Addressed Include:

Low-Calorie Diets and Low T3

One of the most common symptoms I hear from female patients with Thyroid problems has to do with weight gain. More often than non, I see my female patients embark on low calorie diets. What I want you to know is that Low-calorie diets can be damaging to thyroid function and may reduce T3 concentrations by up to 50 percent (1).

When you severely restrict calories, your body will redirect your thyroid hormone (T4) into the reverse T3 version, which causes a drop in your metabolism (2). This is a protective mechanism to prolong your survival in times of famine and food restriction.

I see patients every day that have health histories that scream thyroid problems, yet they continue to suffer because no one ever looked at the whole picture. T3 levels are rarely ever used in thyroid screening panels, so the T4 to T3 conversion pattern is often missed. When it is found, additional testing to determine the cause of the Thyroid under conversion should be investigated. It’s a big problem, since this is such a common thyroid dysfunctional pattern.

Dr Hagmeyer Explains 5 of The Biggest Mistakes Thyroid Sufferers Make 1

Our Personal Thyroid Treatment Program Is A Great place To Start

The Personal Program Thyroid Recovery Program is a Natural Holistic Functional Medicine Based Treatment for people suffering with Thyroid Problems. Our office utilizes nutritional
supplements, Dietary modifications, Nutritional Counseling, Advanced Testing, Hormone and endocrine support formula, Dietary assessment, and lifestyle guidance.

Our Personal Thyroid Recovery Program Is Customized to the Individual Not The Disease.

The Personal Program Thyroid Recovery Program is a Natural Supportive Treatment for Low Thyroid function, Hypothyroidism, Hyperthyroidism and Hashimoto’s disease. Our office utilizes nutritional supplements, Dietary modifications, Hormone and endocrine support formula, and lifestyle guidance.

  • To Schedule a Free 15 minute Phone Consult to see if this program is right or to learn more about Dr Hagmeyer’s program,  Start Here
  • Still have questions? Our Free 15 minute personalized Phone consult is a great place to start.

We’re here to listen and help you through this frustrating and confusing time. Each person suffering with Thyroid symptoms problem has a different set of mechanisms or causes. Our office will customize a Thyroid Restoration Program based on your testing and  tailored to your individual needs.

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Most Popular Read Articles by Dr Hagmeyer

  1. Other Patterns of Thyroid disease that Don’t show up on standard Thyroid Testing
  2. How High Levels of Stress affect Thyroid Function
  3. Is your Blood Sugar Sabotaging your Thyroid- How Blood Sugar Dys-regulation impacts Thyroid Function 
  4. Most Frequently Asked Questions about Thyroid Disease 
  5. Lets Talk about the Thyroid Gland| Struggling with Weight gain, Hair loss, Fatigue
  6. How To Properly Get Tested for Hashimotos and Why Most Doctors Miss it.  
  7. 6 Warning Signs Your Thyroid Disease Is Being Mismanaged.


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