Total T4
Total T4 measures both protein-bound and free thyroxine in blood. Because more than 99 percent is bound to thyroid binding globulin, albumin, and transthyretin, total T4 is influenced by changes in binding proteins caused by pregnancy, estrogen, or liver disease. Free T4 is preferred in most clinical settings for assessing thyroid status.
Optimal range: who says what
No institution or named practitioner we track states an optimal target for Total T4. How we verify ranges.
- General guidance, no named sourceMid-referenceNo separate optimal; free T4 is the more meaningful measure
- Lab reference interval4.5-12.0 μg/dLWhat a lab report flags against. A lab interval is not an optimal target.
4 providers include this
Thyroid Function
Why Total T4 matters
Measures bound and free T4. Less useful than free T4 since affected by binding proteins. Can be misleading in pregnancy or estrogen use.
Which Providers Test Total T4?
Cheapest: Mito Health at $297/year. Most comprehensive: Vitality Blueprint Elite, 138 biomarkers for $700/year.
4 panels that include it, cheapest first
| Provider | Annual Cost | Total Biomarkers | $/Biomarker |
|---|---|---|---|
| $297 | 100+ | $2.97 | |
 Superpower | $349 | 100+ | $3.49 |
| $365 | 100+ | $3.65 | |
| $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.
17 itemized panels do not include Total T4
WHOOP Advanced Labs · Labcorp OnDemand · Life Extension Elite · Everlywell · InsideTracker · Function Health · Marek Health Base · Marek Health Comprehensive · Marek Health Complete · Marek Health Executive · 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 Total T4. 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
Experts discussing Total T4
Podcast episodes where clinicians and researchers cover this marker in depth. Curated by hand; an episode is listed only when the marker is a substantial topic, not a passing mention.
Frequently Asked Questions
What is the optimal range for Total T4?
No institution or named practitioner we track states an optimal target for Total T4. General guidance without a named source: Mid-reference (No separate optimal; free T4 is the more meaningful measure). Lab reference interval: 4.5-12.0 μg/dL. That is what a lab report flags against, not an optimal target.
Which blood test providers include Total T4?
4 of the 21 blood testing panels we itemize marker by marker include Total T4 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