Summarized by Masters of Longevity from Peter Attia Blog.
A deep AMA episode explains thyroid physiology, testing limitations, and practical approaches to diagnosing and treating thyroid dysfunction and borderline cases.

Key Takeaways
- Free T4, free T3, and TSH are the core thyroid tests and have interpretation limitations when used alone.
- Some patients remain symptomatic on T4-only replacement, and combination T4/T3 therapy may be appropriate in select cases.
- Hashimoto's, pregnancy, reverse T3, excess iodine risks, and supplement claims are reviewed as common clinical considerations.



