Elevated reverse triiodothyronine (rT3) levels can disrupt thyroid hormone signaling. rT3 is an inactive form of T3, the active thyroid hormone. When rT3 is high relative to T3, it can bind to T3 receptors, effectively blocking T3 from exerting its effects on cellular metabolism. This can lead to symptoms of hypothyroidism even when TSH and T4 levels are within normal ranges. Therefore, managing rT3 is crucial for optimal thyroid function. For instance, if a person experiences fatigue, weight gain, and hair loss despite normal standard thyroid tests, high rT3 might be a contributing factor.
Addressing elevated rT3 levels is significant because it allows for more effective utilization of available thyroid hormone. Optimizing thyroid hormone function can improve energy levels, mood, cognitive function, and metabolic rate. Historically, the focus of thyroid management centered primarily on TSH and T4. However, acknowledging rT3 provides a more complete understanding of thyroid hormone metabolism and potential imbalances. Benefits of lowering high rT3 include restoring proper thyroid function and alleviating associated symptoms.