What Is Reverse T3?
Reverse T3 (rT3) is a hormone made from T4, the inactive form of thyroid hormone. It competes with active T3 at the cellular level but does not activate your metabolism. Instead, it acts like a blocker, slowing everything down.
What Happens When Reverse T3 Is Too High?
When rT3 levels are elevated, your cells can’t access the energy they need—even if your TSH and T4 look normal. You may feel tired, foggy, and stuck in slow motion. This is because high rT3 blocks your active T3 from doing its job.
Many people with elevated reverse T3 experience symptoms like:
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Fatigue and low energy
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Weight gain or difficulty losing weight
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Brain fog and poor focus
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Cold hands and feet
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Hair thinning
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Constipation
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Depression or anxiety
If these symptoms sound familiar—but your thyroid labs say you’re “normal”—reverse T3 might be the missing piece.
What Causes Reverse T3 to become elevated?
Several factors can raise reverse T3 levels:
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Significant weight loss or very low-calorie diets
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Chronic stress, which raises cortisol
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Inflammation or infections
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Autoimmune diseases such as Hashimoto’s thyroiditis, lupus, rheumatoid arthritis, or ulcerative colitis
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Certain medications, including beta-blockers and steroids
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GLP-1 weight loss medications, which may cause hormonal shifts, including thyroid hormones
Your body may create more rT3 as a survival strategy—essentially putting the brakes on your metabolism to conserve energy.
How Can You Know If It’s Elevated?
The only way to find out is through a complete thyroid panel that includes free T3, free T4, TSH, and reverse T3. Many standard thyroid tests skip rT3—so you have to ask for it specifically. Dr. Helene conducts comprehensive hormone testing for overall health and optimal wellness.
What Can You Do About It?
The solution depends on the root cause. Treatment might include:
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Stress reduction techniques and adrenal support
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Micronutrient testing and nutritional support with selenium, zinc, and B vitamins
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Balancing your diet and calories to avoid starvation mode
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Treating infections or underlying inflammation
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Adjusting medications under your provider’s guidance
If you suspect your metabolism is blocked, testing your reverse T3 could give you clarity—and finally help you feel better.
In Health,
Dr. Helene
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