Hormone Health Hub: Expert Insights on Testing, Balance & Better Living — thyroid hyperactivity

The thyroid is a small butterfly-shaped gland located in the front of the neck, just below the Adam's apple. It plays a crucial role in regulating various bodily functions by producing hormones that control metabolism and energy production. Thyroid hormones, primarily thyroxine (T4) and triiodothyronine (T3), influence the functioning of almost every organ in the body, including the heart, brain, muscles, and skin.The thyroid gland functions under the control of the hypothalamus and the pituitary gland. The hypothalamus releases thyrotropin-releasing hormone (TRH), which signals the pituitary gland to release thyroid-stimulating hormone (TSH). TSH then stimulates the thyroid gland to produce...

Reverse T3 (rT3) is one of the most misunderstood markers in thyroid testing. Often called the “hibernation hormone,” it is frequently claimed — without scientific basis — to block thyroid receptors and slow metabolism. In Part 2 of this series, Margaret Groves of ZRT Laboratory examines what the peer-reviewed literature actually says about rT3, when elevated levels are clinically meaningful, and how to interpret the T3/rT3 ratio in the context of a comprehensive thyroid assessment.