Complete Testing & Optimization Guide
Optimal ranges, provider comparison, and strategies to improve your Total T4 levels
Only 3 providers include this test
Thyroid Function
4.5-12.0 μg/dL
Abnormal Total T4 levels can indicate underlying health issues that may go undetected without proper testing. Regular monitoring helps catch problems early when they're most treatable.
Understanding your Total T4 levels enables targeted interventions, tracks treatment effectiveness, and helps optimize your overall health and performance.
Total thyroxine in blood (bound and unbound)
Measures bound and free T4. Less useful than free T4 since affected by binding proteins. Can be misleading in pregnancy or estrogen use.
4.5-12.0 μg/dL
| Provider | Includes Test | Annual Cost | Total Biomarkers |
|---|---|---|---|
 Superpower | ✓ | $199 | 100+ |
 WHOOP Advanced Labs | — | $349 | 65 |
 Labcorp OnDemand | — | $398 | 30+ |
| — | $486 | 40+ | |
| — | $468 | 83 | |
| ✓ | $798 | 100+ | |
 InsideTracker | — | $680 | 48 |
 Function Health | — | $499 | 100+ |
| — | $900 | 70+ | |
| ✓ | $1150 | 110 | |
| — | $Varies | 75+ |
Choose from 3 providers that include this biomarker in their panels
Total T4 is a thyroid function biomarker that Total thyroxine in blood (bound and unbound) The normal reference range is 4.5-12.0 μg/dL. Regular testing helps track changes and identify potential health issues early.
3 out of 10 major blood testing providers include Total T4 in their standard panels. These include Superpower, Blueprint, Mito Health.
For most people, testing Total T4 2-4 times per year is recommended to establish baseline levels and track trends. If you have abnormal results or are actively working to optimize this biomarker, more frequent testing (quarterly) may be beneficial. Always consult with your healthcare provider for personalized testing frequency recommendations.
The standard laboratory reference range for Total T4 is 4.5-12.0 μg/dL. However, many functional medicine practitioners recommend tighter "optimal" ranges for peak health and performance. Your ideal range may vary based on your age, sex, health goals, and other individual factors. Work with a healthcare provider familiar with optimal ranges to determine your target levels.
Most direct-to-consumer blood testing services that include Total T4 provide the physician order as part of their service. However, some states have restrictions on direct-to-consumer testing. Check with your chosen provider about availability in your state and whether they provide the necessary physician authorization.
Measures bound and free T4. Less useful than free T4 since affected by binding proteins. Can be misleading in pregnancy or estrogen use.
This information is for educational purposes only and is not medical advice. Always consult with a qualified healthcare provider about your specific health needs and before making decisions about blood testing.
