All markers › Thyroid
Free T3
The active thyroid hormone that drives metabolism and energy.
Dr. Sorrell's optimal rangeRead alongside measured resting metabolic rate (flag if low RMR with free T3 <2.9 pg/mL)From the Sorrell MD Lab Decoder. Optimal ranges are stricter than the "normal" range printed on a lab report.
Who includes it, and what it costs
| Provider | Included / price | Checked |
|---|---|---|
| Function Health | ✓ included | 2026-10-16 |
| Superpower | add-on | 2026-10-16 |
| Jinfiniti AgingSOS Cellular Essentials | — | — |
| Quest (questhealth.com) | $149 Comprehensive Thyroid Test Panel | 2026-10-16 |
| Labcorp OnDemand | $89 Free T3 Test (sale $66.75) | 2026-10-16 |
| Walk-In Lab | $59 Tri-iodothyronine (T3) Free Serum Test | 2026-10-16 |
| Ulta Lab Tests | $27.95 T3 Free Test | 2026-10-16 |
| Mito Health | $9.83 non-member price; member $7.02 | 2026-10-16 |
| Rythm Health | ✓ included | 2026-10-16 |
| SiPhox Health | — | — |
| Everlywell | — | — |
| LetsGetChecked | — | — |
Memberships (Function, Superpower) and Jinfiniti's panel cover many markers for one price. See the home page. Quest and Walk-In Lab add a physician fee of about $6 per order.