Estrogen Isn't One Hormone: The Truth About Estradiol, Estrone & Estriol

When someone says, "estrogen causes cancer" or "estrogen causes blood clots," what estrogen are they talking about? In this episode, Dr. Brendan McCarthy explains one of the biggest misconceptions in hormone replacement therapy (HRT): estrogen isn't a single hormone—it's a family of hormones. Understanding the differences between estradiol, estrone, and estriol can completely change how you view your treatment, your lab work, and the conversations you have with your healthcare provider. You'll learn why the type of estrogen, how it's delivered (oral, patch, injection, pellet), and how it's monitored all matter. Dr. McCarthy also discusses why informed consent goes beyond signing paperwork—it means truly understanding the treatment you're receiving and why it was chosen for you. In this episode: What estradiol, estrone, and estriol actually do Why estrogen is a family—not a single hormone How oral estrogen differs from patches, injections, and pellets Why delivery method changes how your body metabolizes estrogen The difference between bioidentical, synthetic, and animal-derived estrogens Why lab timing and monitoring are essential for safe HRT The importance of true informed consent in hormone therapy Four questions every patient should ask before starting estrogen 📚 Download the free research resources and citations: Visit www.protealife.com for episode notes, references, and educational materials.   Dr. Brendan McCarthy is the founder and Chief Medical Officer of Protea Medical Center in Arizona. With over two decades of experience, he’s helped thousands of patients navigate hormonal imbalances using bioidentical HRT, nutrition, and root-cause medicine. He’s also taught and mentored other physicians on integrative approaches to hormone therapy, weight loss, fertility, and more. If you’re ready to take your health seriously, this podcast is a great place to start. 👇 Tap Subscribe to learn more about what’s actually happening in your body, and what to do about it. 📘 Read Dr. McCarthy’s Book: Jump Off the Mood Swing – A Sane Woman’s Guide to Her Crazy Hormones https://www.amazon.com/Jump-Off-Mood-... 📲 Follow Dr. McCarthy: Instagram: @drbrendanmccarthy TikTok: @drbrendanmccarthy Website: www.protealife.com 💬 Got a question or topic for a future episode? Let us know in the comments!