Antonio Bianco is a world-renowned physician-scientist & expert in thyroid physiology & metabolism. In this episode, Antonio explores the complex biology of thyroid hormone production, conversion, & regulation—highlighting how deiodinase enzymes modulate hormone activity at the tissue level & why that matters for interpreting lab results. He discusses the shortcomings of relying solely on TSH as a marker of thyroid function, the ongoing debate around combination therapy with T3 & T4 versus standard T4 treatment, & how genetics, tissue sensitivity, & individual variability influence thyroid hormone metabolism. The conversation also examines how hypothyroidism affects energy, mood, cognition, & longevity; why some patients remain symptomatic despite “normal” labs; & how future research could reshape treatment paradigms. View show notes here: https://bit.ly/4i0e7lF Become a member to receive exclusive content: https://peterattiamd.com/subscribe/ Sign up to receive Peter's email newsletter: https://peterattiamd.com/newsletter/ 0:00:00 - Intro 0:00:11 - How the thyroid produces, stores, & activates hormones like T4 & T3 to finely regulate thyroid activity 0:11:08 - How fasting alters thyroid hormones to conserve energy 0:18:07 - Action of the deiodinases: how D1, D2, & D3 enzymes control the activation & inactivation of thyroid hormones 0:22:59 - The normal function of thyroid hormone & the roles of the hypothalamus, pituitary gland, & deiodinases in maintaining hormonal balance 0:34:12 - Why understanding thyroid physiology is essential for proper diagnosis & treatment of hypothyroidism 0:37:03 - Testing for thyroid hormones: understanding free vs. total levels, the limitations of current T3 assays, best practices 0:45:40 - Genetic & sex-based variability in thyroid hormone regulation & their limited clinical significance 0:48:23 - Hyperthyroidism: causes, symptoms, diagnosis, & treatment options 1:00:10 - Hypothyroidism: diagnosis & autoimmune causes of hypothyroidism 1:09:34 - More on hypothyroidism: diagnostic biomarkers, antibody patterns, & non-autoimmune presentations 1:20:58 - Thyroid hormone replacement therapy 1:35:35 - More on thyroid replacement strategies: exploring the evidence gaps, mortality signals, effects on lipids 1:43:25 - Hypothyroidism basics: causes, antibody implications (including pregnancy), & how to make the diagnosis before choosing therapy 1:52:11 - Thyroid medication: compounded controlled-release T3, brand name versus generic, & what Antonio prescribes to newly diagnosed hypothyroid patients 2:05:26 - Redefining treatment success: why normalizing TSH isn’t always enough for patients with hypothyroidism 2:08:22 - Case studies: analysis of two unusual cases of thyroid disease 2:18:45 - Dangers of supplementing with high levels of iodine, & female-specific risk of thyroid disease 2:23:09 - Case study of a patient who presents with elevated TSH but no symptoms 2:27:54 - How future research could reshape treatment, & Antonio’s new book -------- About: The Peter Attia Drive is a deep-dive podcast focusing on maximizing longevity, and all that goes into that from physical to cognitive to emotional health. With over 90 million episodes downloaded, it features topics including exercise, nutritional biochemistry, cardiovascular disease, Alzheimer’s disease, cancer, mental health, and much more. Peter Attia is the founder of Early Medical, a medical practice that applies the principles of Medicine 3.0 to patients with the goal of lengthening their lifespan and simultaneously improving their healthspan. Learn more: https://peterattiamd.com Connect with Peter on: Facebook: http://bit.ly/PeterAttiaMDFB Twitter: http://bit.ly/PeterAttiaMDTW Instagram: http://bit.ly/PeterAttiaMDIG Subscribe to The Drive: Apple Podcast: http://bit.ly/TheDriveApplePodcasts Overcast: http://bit.ly/TheDriveOvercast Spotify: http://bit.ly/TheDriveSpotify Google Podcasts: http://bit.ly/TheDriveGoogle Disclaimer: This podcast is for general informational purposes only and does not constitute the practice of medicine, nursing, or other professional healthcare services, including the giving of medical advice. No doctor-patient relationship is formed. The use of this information and the materials linked to this podcast is at the user's own risk. The content on this podcast is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Users should not disregard or delay in obtaining medical advice for any medical condition they have, and they should seek the assistance of their healthcare professionals for any such conditions. I take conflicts of interest very seriously. For all of my disclosures and the companies I invest in or advise, please visit my website where I keep an up-to-date and active list of such companies. For a full list of our registered and unregistered trademarks, trade names, and service marks, please review our Terms of Use: https://peterattiamd.com/terms-of-use/