Dr. Tabatha BarberI teach women how to fast their way to a faith-filled, hormonally balanced, fabulous life!

Thyroid Hormones Explained: Free T3 vs Reverse T3 #shorts

21 May 2026 · 1 min

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0:37

In this concise YouTube short, Dr. Tabatha Barber explains the difference between free T3, the active thyroid hormone that drives metabolism, and reverse T3, an inactive form that acts as a physiological “survival mode” signal. She describes how reverse T3 is produced during severe stress—such as life‑threatening injury, car accidents, or intensive‑care situations—to deliberately down‑regulate energy‑expensive processes like fat burning, hair growth, and decision‑making, allowing the body to focus on basic survival. The video emphasizes that this response is a built‑in protective mechanism rather than a pathology.

Chapters

We wanna look at free T3, your active thyroid hormone. We wanna look at reverse T3, the anti-thyroid hormone. Basically reverse T3, it puts your body into survival mode. It shuts things down. And it's built into our bodies beautifully because we need it in times of crisis. If you are fighting for your life, if you're in a car accident, if you're lying in the ICU or the ER, We hope that your reverse T3 is elevated because at that point in time you don't need to burn body fat, you don't need to grow your hair, you don't need to make major decisions or feel good. You need to lie there and survive.