Hypothyroid Symptoms, But Thyroid Test Is Normal, Now What?

February 12, 2023

Many patients can improve their health by properly adjusting their thyroid function, but this area of medicine is often mismanaged and under-evaluated due to incomplete testing. If you have already tested T4 and T3, free and total, TPO Antibodies, Thyroglobulin Antibodies, Reverse T3, and Thyroglobulin, what other tests should be considered?

Clinicians often see patients who test normal for thyroid function but still experience symptoms such as difficulty losing weight, fatigue, hair loss, and constipation. These patients may see some improvement in their symptoms when their thyroid is treated, but their symptoms may not disappear entirely.

To further understand these persistent symptoms, a good next step is to consider an Advanced Intestinal Barrier Assessment and an Oxidative Stress Test.

Why are these tests important?

a) Oxidative stress can impair the activity of glutathione peroxidase, the major antioxidant system in the thyroid. Low levels of glutathione peroxidase are associated with an increase in oxidative stress, which can decrease the function of T4 and T3, even if their levels are normal. Oxidative stress can also reduce the conversion of T4 to T3. By addressing oxidative stress, you can improve the function of thyroid hormones and increase the conversion of T4 to the more active T3.

b) High levels of LPS, as indicated by the Intestinal Barrier Assessment, can cause down-regulation of thyroid receptors. LPS can also affect the conversion of T4 to T3. If there are high levels of LPS, you may have normal levels of hormones but no receptors for them to bind to, resulting in symptoms of hypothyroidism even though your test results are normal.

Here are some studies that support the idea that oxidative stress and gut health can affect thyroid function:

  1. "The role of oxidative stress in the pathogenesis of thyroid diseases." (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5664067/)
  2. "The gut-thyroid axis: a critical interplay in health and disease." (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6493369/)
  3. "The gut-thyroid connection: how dysbiosis contributes to hypothyroidism." (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7016616/)
  4. "Gut microbiota and its relationship with thyroid hormones: a systematic review." (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7384199/)

These studies provide evidence that oxidative stress and gut health can play a role in thyroid function and support the idea of considering an Advanced Intestinal Barrier Assessment and Oxidative Stress Test in patients with persistent symptoms of hypothyroidism despite normal test results.