What is a good Free T4 level?

BioForge works to an optimal range rather than the lab's reference flag. For Free T4 that is 1.0–1.5, measured in ng/dL. A result inside the lab's normal range can still sit outside the range where most people feel and function well.

Learn · Thyroid

Free T4

Measured in ng/dL

The storage form of thyroid hormone circulating in your blood, waiting to be activated.

What the numbers mean

These are the ranges BioForge works to. They are not the same as a lab's reference range, which is built from the general population rather than from people who feel well.

Low

<0.82

Optimal

1.0–1.5

High

>1.77

What moves Free T4

Reflects thyroid gland output and any thyroid medication. Suppressed by severe illness, extreme calorie restriction, and some medications (lithium, amiodarone).

Related markers in Thyroid

TSH Free T3 Reverse T3 TPO Antibodies Thyroglobulin Antibodies Iodine, Serum

This page is educational and is not medical advice. Ranges are general and do not account for your history, medications or symptoms — a single number never decides a protocol. Your results are interpreted by a licensed clinician alongside everything else about you. Back to the Learning Center

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