Causes of Low T3 Levels in Thyroid Health

Wondering what the thyroid levels from your thyroid lab test mean? I’ll break down what the different thyroid hormones indicate and dispel some misconceptions about which levels actually require medication. 

If you have any additional questions you would like answered in the future, let me know in the comments!

• Optimal Thyroid Levels: https://drruscio.com/optimal-thyroid-levels 

• Hyperthyroidism vs Hypothyroidism: https://drruscio.com/hyperthyroidism-vs-hypothyroidism/ 

• Early Signs of Thyroid Problems: https://drruscio.com/what-are-early-warning-signs-of-thyroid-problems/ 

• How to Get Off Thyroid Medication Naturally: https://drruscio.com/how-to-get-off-thyroid-medication/ 

• Thyroid & Hair Loss: https://drruscio.com/thyroid-hair-loss/ 

• Why Your Thyroid Diagnosis Might Be a MISDiagnosis: https://drruscio.com/thyroid-diagnosis/ 

00:00 Intro to the thyroid  

03:57 TSH

05:02 Free T4 

05:59 Free T3 

07:07 TPO (thyroid antibodies) 

08:13 Hashimoto’s 

10:00 TG (thyroglobulin) 

12:58 Defining hypothyroidism

13:27 Defining hyperthyroidism 

13:48 The grey area “Sluggish thyroid”

18:07 Treatments 

20:20 Where symptoms can come from

24:25 Thyroid lab interpretation guide

• Physiology, Thyroid: https://pubmed.ncbi.nlm.nih.gov/30137850/ 

• Serum TSH, T(4), and thyroid antibodies in the United States population (1988 to 1994): National Health and Nutrition Examination Survey (NHANES III): https://pubmed.ncbi.nlm.nih.gov/11836274/ 

• Serum thyrotrophin and circulating thyroglobulin and thyroid microsomal antibodies in a Finnish population: https://pubmed.ncbi.nlm.nih.gov/760358/ 

• The prevalence of undiagnosed thyroid disorders in a previously iodine-deficient area: https://pubmed.ncbi.nlm.nih.gov/14558922/ 

• Hypothyroidism Prevalence in the United States: A Retrospective Study Combining National Health and Nutrition Examination Survey and Claims Data, 2009-2019: https://pubmed.ncbi.nlm.nih.gov/36466005/ 

• Correlation between sonography and antibody activity in patients with Hashimoto thyroiditis: https://pubmed.ncbi.nlm.nih.gov/24154902/ 

• Laboratory Testing in Thyroid Conditions - Pitfalls and Clinical Utility: https://pubmed.ncbi.nlm.nih.gov/30215224/ 

• Hashimoto thyroiditis: an evidence-based guide to etiology, diagnosis and treatment: https://pubmed.ncbi.nlm.nih.gov/35243857/ 

• Anti-Thyroperoxidase Antibody Levels >500 IU/ml Indicate a Moderately Increased Risk for Developing Hypothyroidism in Autoimmune Thyroiditis: https://pubmed.ncbi.nlm.nih.gov/27607246/ 

• Hyperthyroidism: https://pubmed.ncbi.nlm.nih.gov/32206604/ 

• Subclinical Hypothyroidism: https://pubmed.ncbi.nlm.nih.gov/30725655/ 

• Transient high thyroid stimulating hormone and hypothyroidism incidence during follow up of subclinical hypothyroidism: https://pubmed.ncbi.nlm.nih.gov/34879182/ 

• Association of Thyroid Hormone Therapy With Quality of Life and Thyroid-Related Symptoms in Patients With Subclinical Hypothyroidism: A Systematic Review and Meta-analysis: https://pubmed.ncbi.nlm.nih.gov/30285179/ 

• Treating hypothyroidism is not always easy: When to treat subclinical hypothyroidism, TSH goals in the elderly, and alternatives to levothyroxine monotherapy: https://pubmed.ncbi.nlm.nih.gov/34766382/ 

• Symptoms Originally Attributed to Thyroid Dysfunction Were Instead Caused by Suboptimal Gastrointestinal Health: A Case Series and Literature Review: https://pubmed.ncbi.nlm.nih.gov/35999903/ 

• The Relationship between Gastrointestinal Health, Micronutrient Concentrations, and Autoimmunity: A Focus on the Thyroid: https://pubmed.ncbi.nlm.nih.gov/36079838/ 

• Combined treatment with Myo-inositol and selenium ensures euthyroidism in subclinical hypothyroidism patients with autoimmune thyroiditis: https://pubmed.ncbi.nlm.nih.gov/24224112/ 

• Effects of vitamin D on thyroid autoimmunity markers in Hashimoto's thyroiditis: systematic review and meta-analysis: https://pubmed.ncbi.nlm.nih.gov/34871506/ 

• Probiotics Ingestion Does Not Directly Affect Thyroid Hormonal Parameters in Hypothyroid Patients on Levothyroxine Treatment: https://pubmed.ncbi.nlm.nih.gov/29184537/ 

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DISCLAIMER: The information on this site is not intended or implied to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of your physician or other qualified healthcare provider before starting any new treatment or discontinuing an existing treatment.

Music featured in this video: "Modern Technology" by Andrew G, https://audiojungle.net/user/andrew_g 

*Full transcript available on YouTube by clicking the “Show transcript” button on the bottom right of the video.