Thyroid health is one of the most overlooked topics in bodybuilding, performance enhancement, and hormone optimization—and in this episode, Big Paul sits down with Optimal Nathan for a deep dive into how the thyroid actually works. This is Part 1 of the conversation. Check out Part 2 on Optimal Nathan’s channel for the continuation. https://www.youtube.com/@UCuupll5hz3ry9uQKYAfmZkw We break down thyroid hormones like T3, T4, TSH, and reverse T3, while exploring why standard thyroid labs may not always tell the full story. Nathan explains thyroid hormone production, conversion, cellular uptake, mitochondrial function, and the role thyroid signaling may play in metabolism, energy, muscle growth, cognition, and overall performance. The conversation also dives into growth hormone and thyroid function, including why GH can affect T4 and T3 levels, the importance of thyroid hormone conversion, and why simply trying to “fix” an abnormal lab value may miss the bigger picture. Other topics discussed include: • T3 vs. T4 and thyroid hormone conversion • Growth hormone, IGF-1, and thyroid function • D1, D2, and D3 deiodinase enzymes • Why thyroid activity can differ between tissues • TSH, free T3, free T4, and reverse T3 • Genetics and thyroid hormone conversion • Thyroid function during bodybuilding prep and dieting • Carbohydrates and thyroid metabolism • Iodine, selenium, zinc, iron, copper, and thyroid health • Hashimoto’s, Graves’ disease, and autoimmune thyroid issues • Mitochondrial function and cellular energy production • Common mistakes with thyroid supplementation • Why symptoms and bloodwork need to be evaluated together If you’re interested in bodybuilding, hormone optimization, biohacking, thyroid health, growth hormone, metabolism, or performance enhancement, this conversation is packed with information that may change the way you think about thyroid function. 📧 For exclusive inside Information and free articles, join my mailing list: https://www.anabolicbodybuilding.com/email-list Subscribe to my Clips Channel: https://www.youtube.com/@UCjQmfhe1yyDsRjCVedA5IBA 🎓 Mentorship Group: https://www.skool.com/big-pauls-mentorship/about 📘 The Science of Anabolics E-Course: https://www.anabolicbodybuilding.com/the-science-of-anabolics-performance-enhancing-drugs 🗺️ Get The Ultimate Cycle Cheat Sheet: https://www.anabolicbodybuilding.com/cheatsheet 💪 Team ANABOLIC BODYBUILDING: https://www.skool.com/teamanabolicbodybuilding 💪 For Coaching or Consultations, go to: https://www.anabolicbodybuilding.com/ 📧 Contact BigPaul at: https://zl3h1q0lbmt.typeform.com/to/vqzGP4mG SOCIAL MEDIA 🤘 Instagram: https://www.instagram.com/paulkbarnett/ 🔈 Spotify: https://open.spotify.com/show/3PKOCKSDh6ZeaLmVoHF60z 🆇 Formerly Twitter: https://twitter.com/paulb3rd 🤮 Facebook: https://www.facebook.com/officialanabolicbodybuilding/ 🎬 RUMBLE: https://rumble.com/c/AnabolicBodybuilding 🍏 Apple Podcasts: https://podcasts.apple.com/us/podcast/anabolic-bodybuilding/ 📘 E-Books: https://www.anabolicbodybuilding.com/ebooks 💪 FREE Training Programs: https://www.anabolicbodybuilding.com/free_stuff 🧪 For Blood Panels: www.UltaLabTests.com/bigpaulmedia 📘 E-Books: https://www.anabolicbodybuilding.com/ebooks 💪 FREE Training Programs: https://www.anabolicbodybuilding.com/free_stuff #Thyroid #ThyroidHealth #T3 #T4 #HormoneOptimization #Bodybuilding #GrowthHormone #IGF1 #Metabolism #Biohacking #PerformanceEnhancement #Hashimotos #Hypothyroidism WARNING ======== The Video has been made available for entertainment and educational purposes only. I do not make any warranties to the accuracy, applicability, fitness, or completeness of the content. The content is not intended to be a substitute for professional medical or legal advice, diagnosis, or treatment. Always seek the advice of your physician or qualified health provider. Never disregard professional medical advice or delay in seeking it because of something you have seen on this channel. I hereby disclaim any and all liability to any party for any direct, indirect, implied, punitive, special, incidental, or other consequential damages arising directly or indirectly from any use of the content, which is provided as is, and without warranties.