🐊GATOR
Thyroid

Reverse T3 (rT3)

Reverse T3 is an inactive form of thyroid hormone produced when the body converts T4 to rT3 instead of active T3. Elevated rT3 can cause hypothyroid symptoms despite normal TSH and T4.

Common in chronic stress, caloric restriction, illness, and overtraining.

What It Measures

Concentration of inactive reverse T3 hormone.

Reference Ranges

StatusRange (ng/dL)
Optimal9.2–24.1 ng/dL
Normal9.2–24.1 ng/dL
Borderline> 24.1 ng/dL
Out of Range> 30 ng/dL

How GATOR Tracks This

Lab Providers

Function HealthLabCorp

Related Clinical Ratios

FT3/RT3

Related Biomarkers

This content is for informational purposes only and does not constitute medical advice. Reference ranges may vary by laboratory and individual factors. Consult a qualified healthcare provider for interpretation of your results and treatment decisions.

Track Reverse T3 in GATOR

Import your lab results and see how this biomarker trends over time with AI-powered context.

Get Started Free