What is a normal total T4 level?
The short answer
A typical US lab prints a normal total T4 range of 4.5–12 µg/dL. That range exists to catch disease, not to describe your best.
Nobody we follow has said what your Total T4 should be. It comes up on the shows, but never with a number.
What Total T4 measures
All the main thyroid hormone in your blood, both bound and unbound.
Binding proteins shift with pregnancy and medication, so the free form is often the clearer read.
Checked against MedlinePlus — Thyroxine (T4) Test.
Common questions
What is a normal Total T4 level?
Most US labs print 4.5–12 µg/dL. Your report grades you against that range. It exists to catch disease, not to describe your best.
What does your Total T4 number mean?
On a typical lab range, under 4.5 µg/dL is low, 4.5 to 12 is normal and over 12 is high. Your own report prints its range next to your number, and that is the one your lab uses. Nobody we follow has drawn a line inside that range.
What does the Total T4 test measure?
All the main thyroid hormone in your blood, both bound and unbound. Binding proteins shift with pregnancy and medication, so the free form is often the clearer read.
Why is there no target here?
Because nobody we follow has named a number for Total T4. If that changes, it will be here.