T3 Uptake
T3 uptake is an indirect measure of how much thyroid hormone-binding protein is available to bind added labeled T3. It was historically combined with total T4 to calculate the free thyroxine index before direct free T4 assays became widely available. Results are affected by estrogen, pregnancy, and certain drugs, and the test is now used less often.
Optimal range: who says what
No institution or named practitioner we track states an optimal target for T3 Uptake. How we verify ranges.
- General guidance, no named sourceWithin referenceIndirect binding measure; no separate optimal. Largely superseded by direct free T4 and free T3 assays
- Lab reference interval24-39%What a lab report flags against. A lab interval is not an optimal target.
2 providers include this
Thyroid Function
Why T3 Uptake matters
Reflects binding protein availability. Used with total T4 to calculate free thyroxine index. Less commonly used with free hormone assays available.
Which Providers Test T3 Uptake?
Cheapest: Superpower at $349/year. Most comprehensive: Vitality Blueprint Elite, 138 biomarkers for $700/year.
2 panels that include it, cheapest first
| Provider | Annual Cost | Total Biomarkers | $/Biomarker |
|---|---|---|---|
 Superpower | $349 | 100+ | $3.49 |
| $700 | 138 | $5.07 |
$/Biomarker is annual cost divided by the panel's advertised biomarker count, not the price of this one test. We track 23 blood test providers (32 plans); 21 of those plans are itemized marker by marker. Compare all of them.
19 itemized panels do not include T3 Uptake
WHOOP Advanced Labs · Labcorp OnDemand · Life Extension Elite · Everlywell · Mito Health · InsideTracker · Function Health · Marek Health Base · Marek Health Comprehensive · Marek Health Complete · Marek Health Executive · Blueprint · Empirical Health · Oura Health Panels · SiPhox Health · Hims Labs · Healthspan · Vitality Blueprint Standard · Ultrahuman Blood Vision Annual
11 providers not itemized in our matrix
We have not itemized these marker by marker (some sell tests one at a time), so this page cannot say whether they offer T3 Uptake. Check with them directly.
Life Extension Standard · Quest Health · Ultrahuman Blood Vision · Lifeforce · Hundred Health · Personalabs · Walk-In Lab · HealthLabs · WHOOP Specialized Panels · Marek Health Essential · Vitality Blueprint Upload
Frequently Asked Questions
What is the optimal range for T3 Uptake?
No institution or named practitioner we track states an optimal target for T3 Uptake. General guidance without a named source: Within reference (Indirect binding measure; no separate optimal). Lab reference interval: 24-39%. That is what a lab report flags against, not an optimal target.
Which blood test providers include T3 Uptake?
2 of the 21 blood testing panels we itemize marker by marker include T3 Uptake in their panels. This biomarker has limited availability.
Related: YouBoost rates lifestyle and supplement interventions by evidence.
Medical Disclaimer
This information is for educational purposes only and is not medical advice. Always consult with a qualified healthcare provider about your specific health needs.
Last reviewed Aug 26, 2026 · First published Sep 30, 2025