Reverse T3 details
What Reverse T3 shows
Reverse T3 is an inactive form of T3 thyroid hormone, produced when your body converts T4 into reverse T3 instead of active T3 — something that can increase during illness, significant physical stress, or calorie restriction, as a way of temporarily slowing metabolism. It's sometimes checked alongside standard thyroid tests (TSH, free T4, free T3) when a thyroid hormone conversion problem is suspected despite normal standard thyroid results, though its clinical usefulness and the reliability of using it to guide treatment decisions is debated among endocrinologists, with mainstream guidelines generally placing less weight on it than on standard thyroid panels.
Normal ranges
Typical adult range
8–25 ng/dL
Most labs report a range close to this
Hormunity optimal range
10–25 ng/dL
A narrower functional target
Each lab sets its own reference range. Always compare your result with the range printed on your report, and review it with a healthcare provider.
Tests that include Reverse T3
Reverse T3 (rT3) is an inactive form of the thyroid hormone T3 that is produced under stress or illness when the body converts T4 into rT3 instead of active T3. It is used to assess thyroid hormone conversion efficiency and may help identify non-thyroidal illness or functional hypothyroidism.
- Reverse T3 An inactive form of T3 thyroid hormone. Sometimes checked alongside standard thyroid tests when thyroid hormone conversion issues are suspected.
Reverse T3 (rT3) is an inactive form of the thyroid hormone T3 that is produced under stress or illness when the body converts T4 into rT3 instead of active T3. It is used to assess thyroid hormone conversion efficiency and may help identify non-thyroidal illness or functional hypothyroidism.
- Reverse T3 An inactive form of T3 thyroid hormone. Sometimes checked alongside standard thyroid tests when thyroid hormone conversion issues are suspected.
Not sure how to read your results? We can help.
Schedule a consultation with a Hormunity specialist. We’ll walk through every marker, interpret what it means for you, and map out the next steps for your care.
Book a specialist