“Normal” Thyroid Labs With Symptoms Hypothyroidism – Low T3 Syndrome
A very common problem that we see in our office everyday is Thyroid Underconversion. It is now widely accepted that there are 6 major patterns of thyroid dysfunction and only 1 of these patterns responds well to thyroid replacement. For the purpose of this post, I will discuss one of the more common patterns called Thyroid underconversion or Low T3. Patients with Thyroid problems often suffer terrible with a laundry list of thyroid symptoms, but when the basic thyroid panel comes back the two main markers(TSH,T4) for hypothyroidism are normal. Why does this happen? If you read on, you will understand.
How is it possible to have thyroid problems with normal labs?
Let me explain.
There is two forms of thyroid hormone. Thyroxine, commonly called T4, and triiodothyroxine, 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.
Your thyroid gland produces predominantly inactive T4. This means that we must convert T4 to T3, called thyroid conversion, in order to have normal thyroid responses. This conversion takes place primarily in the liver and gut mucosa.
What about Reverse T3 and Low Thyroid
Elevated levels of Reverse T3 is a big problem for those Thyroid sufferers who have experienced prolonged stress. in this video below you can learn more about RT3, why you need to have it tested, the T3/Rt3 ratio and more.
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 underconversion of T4 to T3 we can’t have normal thyroid responses. T4 does us no good if we can’t get it into an active form. This thyroid underconversion issue is one of the many reasons why patients with hypothyroid symptoms go undiagnosed and mismanaged.
So What Causes Thyroid Underconversion?
Certain inflammatory cytokines involved in the stress response have been shown to down-regulate the enzyme responsible for peripheral conversion of T4 to T3. Fixing this problem requires lab testing to determine the source of the inflammation. It is necessary to also test the hypothalamus-pituitary-adrenal-axis.
By using natural interventions to normalize the faulty physiology we normalize the T4 to T3 conversion. This is one situation where thyroid hormone replacement would not work because ninety five percent of the time, synthetic T4 is administered, which cannot be converted to the active T3.
Another source of thyroid peripheral underconversion is increased gastrointestinal lipopolysaccharides, an endotoxin produced from bacterial overgrowth aka Leaky Gut.
The primary cause of this is intestinal dysbiosis, or a shift in the good vs. bad bacteria in your gastrointestinal system. What causes this?……unfortunately, its caused by antibiotics, antacids, Standard American Diet (SAD) and anything that reduce stomach acid. This problem is corrected by doing advanced gastrointestinal lab panels and normalizing the findings, with natural interventions. Very rarely does this require medication.
I see patients every day that have histories that scream of a thyroid problem, 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 underconversion pattern is often missed.
When it is found, proper testing to determine the source of the underconversion is not investigated. It’s a big problem, since this is such a common thyroid dysfunctional pattern.
Have questions, you might find them on our FAQ section
I will be posting more information about other pattern of Functional Thyroid disorders in the near future.