Dr. Todd Lee's Everything You Need To Know About THYROID (T3 & T4)

Summarized Bloodwork and Thyroid Hormones:

  1. Key Hormones to Test:
  • TSH (Thyroid Stimulating Hormone)
  • Free T3 (Triiodothyronine)
  • Free T4 (Thyroxine)
  • Reverse T3
  1. Typical Medical Practice:
  • Conventional doctors often only test TSH.
  • High TSH usually results in prescribing synthetic T4 (e.g., Synthroid).
  • This approach is often insufficient because it doesn’t account for how well T4 is converting to T3.
  1. Optimal Blood Levels:
  • Free T3: Aim for 3.5 to 4.3
  • Free T4: Over 1, probably less than 2
  • TSH: Close to 1 is optimal, but not as critical
  • Reverse T3: The lower, the better
  1. Understanding T3 and T4:
  • T4 is converted into the active hormone T3.
  • Reverse T3 is an inactive form, indicating poor conversion from T4 to T3.
  • High Reverse T3 often means that T4 is not adequately converting to T3.
  1. Factors Affecting Thyroid Function:
  • Stress and poor nutrition can hinder the conversion of T4 to T3, increasing Reverse T3.
  • Supplements such as selenium, iodine, magnesium, and zinc can help improve conversion.
  1. Treatment Approach:
  • Instead of only prescribing T4, a combination of T4 and T3 can be more effective.
  • For instance, a combination dose like 50 mcg T4 and 12.5 mcg T3 can be a starting point.
  • Bloodwork should be rechecked to adjust doses based on changes in hormone levels.
  1. Practical Tips:
  • If Reverse T3 is high, addressing factors like selenium and iodine deficiency, and reducing stress can help.
  • A balanced approach to hormone replacement therapy (HRT) includes careful monitoring and adjustments based on detailed blood tests.
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