Why High 'Inactive' Thyroid Hormone Might Worsen Mental Health
The Influence of Reverse Triiodothyronine on Neuropsychiatric Disorders: A Narrative Review.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
This review looks at how a normally inactive thyroid hormone byproduct, called rT3, might actually block active thyroid hormones from working properly in the brain. When the body is stressed or inflamed, it makes more rT3, which can lower brain energy and mood regulation, potentially explaining why some people with mental health conditions don't respond well to standard treatments.
Surprising Findings
rT3, long dismissed as a useless metabolic waste product, actively blocks active thyroid hormone from binding to brain receptors.
Challenges decades of medical teaching that rT3 is biologically inert and merely a byproduct.
Practical Takeaways
If you have persistent depression, anxiety, or brain fog despite normal standard thyroid labs, ask your doctor about checking reverse T3 (rT3) and the T3/rT3 ratio.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
This review looks at how a normally inactive thyroid hormone byproduct, called rT3, might actually block active thyroid hormones from working properly in the brain. When the body is stressed or inflamed, it makes more rT3, which can lower brain energy and mood regulation, potentially explaining why some people with mental health conditions don't respond well to standard treatments.
Surprising Findings
rT3, long dismissed as a useless metabolic waste product, actively blocks active thyroid hormone from binding to brain receptors.
Challenges decades of medical teaching that rT3 is biologically inert and merely a byproduct.
Practical Takeaways
If you have persistent depression, anxiety, or brain fog despite normal standard thyroid labs, ask your doctor about checking reverse T3 (rT3) and the T3/rT3 ratio.
Publication
Journal
Military medicine
Year
2025
Authors
Mark L. Gordon, A. Gregg, Alicja B Poleszak
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Claims (6)
A thyroid hormone byproduct called rT3 might block the active thyroid hormone from working properly in your brain cells. This blockage could lower the hormone's effectiveness, which might play a role in causing certain mental health and brain development issues.
When your body is under long-term stress, trauma, or constant inflammation, it produces more of an enzyme that converts your main thyroid hormone into an inactive form. This leaves your cells starved of active thyroid hormone even though standard blood tests look normal, which can lead to brain fog, low mood, and cognitive problems.
People with certain mental health conditions like depression, bipolar disorder, and schizophrenia often have different thyroid hormone levels in their blood compared to healthy people. Specifically, they tend to have higher levels of a hormone called rT3 and a lower ratio of T3 to rT3. This pattern suggests that these different brain conditions might share the same underlying metabolic issue.
For people with mental health conditions, having higher levels of a specific thyroid hormone byproduct and a lower ratio of active thyroid hormones seems to go hand-in-hand with worse symptoms and less response to usual psychiatric medications. This suggests that how the body processes thyroid hormones might play a direct role in how severe the condition is and how well treatments work.
This claim suggests that checking a specific thyroid hormone called rT3 in the blood could help doctors better understand mood and thinking problems. Adding this test to regular thyroid checks might lead to more accurate diagnoses and treatments tailored to how a patient's body processes hormones.