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

Discover the benefits of hormone testing in saliva, dried blood spot, and dried urine spot methods. Learn how each approach enhances accuracy, convenience, and health insights for hormone balance.

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.