Free T3
Triiodothyronine (T3) is one of the two main hormones the thyroid gland releases into the bloodstream. Free T3 is the portion that is not attached to proteins, so it can enter the body's tissues where it is needed; bound T3 attaches to proteins, which prevents it from entering the tissues.
Why it matters: Together, T4 and T3 play vital roles in regulating the body's metabolic rate, heart and digestive function, muscle control, brain development and bone maintenance.
Source · Cleveland Clinic — what it is, why it matters, what moves it, related conditions
May decrease with:
What is Free T3?
Triiodothyronine (T3) is one of the two main hormones the thyroid gland releases into the bloodstream. Free T3 is the portion that is not attached to proteins, so it can enter the body's tissues where it is needed; bound T3 attaches to proteins, which prevents it from entering the tissues.
What might a high or low Free T3 mean?
Together, T4 and T3 play vital roles in regulating the body's metabolic rate, heart and digestive function, muscle control, brain development and bone maintenance.
What is the typical reference range for Free T3?
The general-population reference range shown here is 3.1 – 6.8 pmol/L. Reference ranges describe the general population and are not a personal target — discuss your results with your physician.
What can affect Free T3?
It may be lower with: Steroid medicines, Amiodarone, Severe illness.