← All Biomarkers

Reverse T3

Thyroid Unit: ng/dL

Inactive T3 metabolite; elevated in non-thyroidal illness

Also known as: rT3,Reverse Triiodothyronine

Reference Ranges

Clinical Reference 9.2 – 24.1 ng/dL
Optimal Range 9.2 – 15.0 ng/dL

Elevated in stress/illness; blocks T3

Related Conditions

Hypothyroidism High

Food & Lifestyle Recommendations

🍎 Food Include selenium-rich foods: Brazil nuts, seafood, eggs Selenium-dependent deiodinase enzymes convert T4 to active T3 rather than reverse T3
🍎 Food Ensure adequate zinc intake: oysters, beef, pumpkin seeds Zinc is involved in thyroid hormone conversion; deficiency may favor reverse T3 production
🧘 Stress Address chronic stress — cortisol impairs T4-to-T3 conversion Elevated cortisol from chronic stress shifts T4 metabolism toward reverse T3 production

Evidence-Backed Supplements

When High

  • Selenium Tier A May Decrease

    Moderate evidence; selenium supports proper T4-to-T3 conversion, reducing reverse T3 accumulation. Deiodinase enzymes are selenium-dependent.

    Reduce selenium intake Consult physician N/A
    PMID 29376219 PMID 23440843 PMID 26214143
  • Zinc Tier A May Decrease

    Limited evidence; zinc is involved in thyroid hormone metabolism. May support conversion of T4 to active T3 rather than reverse T3.

    Zinc picolinate 15–25 mg/day Evening
    PMID 33724446 PMID 36994923 PMID 27996088

Questions to Ask Your Doctor

  • Could my elevated reverse T3 indicate a conversion problem rather than a thyroid production issue? High reverse T3 may indicate impaired T4-to-T3 conversion, often related to stress, illness, or selenium deficiency.

Upload your blood test to see how your Reverse T3 compares to reference and optimal ranges.

Upload Blood Test