Reverse T3 · high result
What does a high Reverse T3 mean?
Short answer
Reverse T3 is an inactive form of thyroid hormone the body makes more of during illness, fasting, severe calorie restriction, surgery, and with some medications (amiodarone, glucocorticoids, beta-blockers). A high level is a marker of that physiological stress — not, by mainstream guidelines, a thyroid disease to treat. It is interpreted alongside TSH, Free T4 and Free T3.
Medically reviewed by Youmna DiStefano, MD · Last reviewed September 2026
What is the normal range for Reverse T3?
- age 18+: 8.00 – 25.0 ng/dL
Can reflect physiological stress, illness, severe dieting, or certain medications.
Full reference table, citations and testing options: Reverse T3 biomarker page.
What are the common causes of high Reverse T3?
- Acute or chronic illness, hospitalization, sepsis
- Fasting, very low-calorie dieting, eating disorders
- Medications: amiodarone, propranolol, glucocorticoids, iodinated contrast
- Levothyroxine dose changes (transient)
- Older age (mild)
What symptoms go with high Reverse T3?
- None from reverse T3 itself; fatigue and cold intolerance are usually from the underlying illness or calorie deficit
What do clinicians usually check next?
- TSH, Free T4 and Free T3 — the actionable thyroid tests
- Review recent illness, dieting and medications
- Retest when well and eating normally; most values normalize
Follow-up tests available at TestWell: TSH (Thyroid Stimulating Hormone) ($26.99), TSH + Free T4 ($27.99), Free T3 (Triiodothyronine) ($30.99), Free T4 (Thyroxine) ($23.99), T3 Uptake ($22.99).
How do you recheck Reverse T3?
Prices are cash-pay; every order adds one $6 lab processing fee. Physician authorization is included; no insurance or referral needed.
| Test or panel | Type | Price | Fasting | Results |
|---|---|---|---|---|
| Complete Thyroid Panel | Panel · 4 tests | $109.99 | No | 3–7 business days |
| Advanced Thyroid Panel | Panel · 7 tests | $129.99 | No | 3–5 business days |
| Men's Hair Health Panel | Panel · 19 tests | $499.99 | No | 4–7 business days |
| Reverse T3 | Test | $35.99 | No | 4–7 business days |
Common questions
Should high reverse T3 be treated with T3 medication?
Major endocrine guidelines do not recommend it. Reverse T3 rises as a normal response to illness and calorie deficit; addressing those, not adding hormone, is the evidence-based path.
Sources
Educational content, not a diagnosis. Lab results are one input; a clinician interprets them with your history and exam.