Thyroid Algorithm

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This information is for educational purposes only, to enable you to have a quality conversation with your doctor who is prescribing the tests and medications. Several additional considerations are required to design this panel for an individual. 

The basic ideas are:

  1. by measuring just three parameters, Free T4, Free T3 and Reverse T3, there are 27 possible scenarios.
  2. If only T4 is adjusted, there are only two possible changes, up or down. If T3 and T4 can be adjusted, there are eight possible changes.
  3. TSH is a measure of pituitary function, not thyroid function. Therefore TSH is not utilized to assess the body’s need for thyroid hormone.


Proof of Components

rT3 blocks production of T3

!A Study of Extrathyroidal Conversion of T4 to T3.1976.r

Cortisol diverts T4 to rT3 rather than T3

Neuroendocrine System Regulatory Mechanisms–Acute Coronary Syndrome.2018

Nonthyroidal Illness Syndrome Across the Ages.2019

Articles Supporting the Need for T3 

Low-T3 Syndrome- A Strong Prognostic Predictor of Death in Patients With Heart Disease.2003

For more information about the benefits and indications for T3, see Combined Thyroid T4-T3 Therapy

Related Pages

Thyroid Testing and Treatment

Thyroid Main

Iodine Main