Expert Guidance From Louise O’Connor - The Thyroid Naturopath { Discover More! }

What Causes High Reverse T3 (RT3)? {There Are 5 Key Reasons}

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what causes high reverse T3Have you been told you have high reverse T3? Please keep reading as this article answers the important question ‘what causes high reverse T3?’

Firstly, How Does High Reverse T3 Impact Your Health?

High reverse T3 has a powerful effect on slowing your metabolism.

As a consequence, excess reverse T3 pushes your body into a HYPOthyroid state which triggers a long list of symptoms. You can learn more here: Do You Suspect You Suffer High Reverse T3 Symptoms?

What Causes High Reverse T3 (RT3)? {There are 5 Key Reasons}

+ Unrelenting physical and emotional stress

Extreme stress causes cortisol to soar. Yes, cortisol is an important hormone that helps you cope with stress. However there’s a flip side to having too much cortisol circulating in your blood stream…it inhibits normal thyroid hormone activity. Overtime this situation leads to excess reverse T3.

WHY does the body produce excess RT3 in times of stress?

Health experts propose it’s a protective response to slow metabolism, and conserve energy to help the body cope with ongoing stress. You see, your body knows it simply cannot survive on high alert for too long. It has the potential to lead to burnout.

+ Extreme, or yo-yo dieting

Did you know cutting calories in an effort to lose weight sparks the body’s hard wired famine response? As food becomes scarce your body feels the need to conserve energy, and it achieves this by putting the brakes on your metabolic rate.

In essence, the easiest and quickest way your body can slow your metabolism, and thereby conserve energy is to produce more reverse T3.

+ Low iron is leaving you tired and breathless

Chronic iron deficiency is a common finding in hypothyroidism. An iron deficiency needs to be addressed as low iron impairs proper thyroid hormone metabolism. More specifically, low iron decreases healthy conversion of thyroxine (T4) to more active triiodothyronine (T3).

Adequate levels of iron are especially important to help fight fatigue as this mineral is required by your red blood cells to carry oxygen around your body. Furthermore, when iron is low your blood oxygen levels are low and your body cannot properly utilize T3 at a cell level.

+ Long term exposure to toxins

Toxins such as heavy metals, pesticides, smoking, and industrial chemicals switch on a physical stress response. It’s widely accepted toxins have a serious effect on your thyroid health.

At a cellular level toxins can block the thyroid cell receptors so the thyroid hormones cannot perform their job, and toxins can enter the thyroid causing damage to the actual thyroid tissue. These factors sabotage day to day function of your thyroid. Over time the stress of dealing with toxins and the diminishing function of the thyroid can activate far greater production of reverse T3.

+ Systemic illness is a factor

It is difficult to recover from reverse T3 dominance when a chronic underlying illness is not addressed. When your body feels under threat by a long standing illness it slows metabolism. Your body hits the ‘hibernation’ button to lessen the impact of a chronic illness.

For example, a latent viral infection may be causing widespread problems. This can lead to chronic fatigue syndrome which is often associated with over production of reverse T3. Treating excess reverse T3 secondary to a specific chronic illness is best discussed with a skilled healthcare practitioner.

What Does The Reverse T3 Blood Measure?

The reverse T3 blood test measures circulating levels of reverse T3. In fact, this is the only test that can be used to check your reverse T3 levels.

  • The reverse T3 test is normally included in a complete thyroid panel. If you wish to learn more about comprehensive testing please view this article: The Top 5 Thyroid Blood Tests. These Thyroid Tests Are Essential. Find Out Why!
  • If you are experiencing hypothyroid symptoms BUT your TSH, free T4, and even your free T3 appear to be normal you should get your reverse T3 checked. In fact, most integrative doctors and Naturopaths now routinely perform this test as it’s considered essential to effectively diagnose, and manage a low thyroid disorder.

what causes high reverse T3

Now I would love to hear from you. Did you find this article on what causes high reverse T3 (RT3) interesting? To leave your comment, feedback or questions about this thyroid health blog post just use the comment box at the bottom of this page.

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  1. Alanyo Alice Grace says:

    I want to acknowledge you for this critical but informative news.
    The symptoms described above seems to be what I am experiencing now. Since all my investigations (exceptT3 not done), were normal, I have all along been on Lugol’s iodine, 2=3 drops per meal without any significant improvement. Instead, the swelling of the (L) thyroid is increasing and those symptoms described are there. How can I be helped?
    Secondly, What are sources of metals described above? In other words, how do we get them into our bodies?
    Thanks a lot

  2. Louise O'Connor says:

    Hi Alice, it is vital to get all five thyroid tests done as this gives you an overall assessment of what is happening with your thyroid hormones. This means getting TSH, free T4, free T3, thyroid antibodies and reverse T3. When free T3 drops below 4.5 pmol/L and reverse T3 is high it is usual to experience hypothyroid symptoms. Unfortunatley heavy metals are pervasive in our food, water and air. For many people silver amalgam dental fillings are a source of mercury. This mercury leaches from the teeth over time and enters general circulation. Your thyroid requires more than iodine. If you are in Australia please take a look at ThyroSynergy. This is a thyroid health product that I developed. It has specially formulated with 10 ingredients to aid thyroid health.

  3. susan fletcher says:

    Hi would uou have a diet plan for low thyroid function im floundering a bit thankyou

  4. Jane Crawforrd says:

    I found this helpful since my lab tests show I have high RT3. However, my ferritin is also high, not low. How does this impact the situation?

    • Louise O'Connor says:

      Hi Jane, raised ferritin is common in hypothyroidism. There’s a number of reasons why. It may not necessarily be related to high RT3 but rather the fact your free T3 is low which decreases digestive function, and other metabolic activity. Best wishes, Louise O’Connor

  5. This was very helpful and validates my thinking that smoking may well have been the big contributor to my elevated RT3, but somewhat depressed T3. I think this was the main cause because otherwise I am very careful about avoiding toxins in products and have maintained a detox regimen over years including a purified zeolite helps remove heavy metals. Also, the article reminded me that dieting and cleansing to very low calorie levels post menopause in my 50s may also have been a cause of my higher RT3. The iron as an factor in hypothyroidism was one I hadn’t heard or thought of before but makes perfect sense the way you explained it. My high quality multi-vitamin does not contain any iron but I do not know what my levels are. I think they were normal, but I only had some fatigue originally, not bad, and don’t have any now, while I’m weaning off the Bio-identical thyroid medication. Sounds like that is a thing to continue monitoring though, even post menopause. Thanks for the very helpful and concise articles!

    • Louise O'Connor says:

      Hi Sophia, diet and lifestyle factors play a major role on our thyroid health. Yes, smoking has a negative impact on thyroid function and this has been validated by scientific studies. You may have uncovered a major cause for elevated RT3. Smoking is a hard habit to break but I hope you have had success. Best wishes, Louise O’Connor

  6. Michelle Gander says:

    In the UK, the standard levothyroxine formula has been refined, and is now, apparently, purer T4 than before… now that it has been refined, it is no longer working for me.. your article on T3 and RT3 has really helped me to convince my GP to do a full thyroid blood test, not just the TSH one, which keeps coming back inconclusive, with too high T4 levels.
    Thank you

    • Louise O'Connor says:

      Hi Michelle, yes, I definitely agree. Comprehensive testing that includes TSH, free T4, free T3, thyroid antibodies and reverse T3 reveals so much more about thyroid function. If free T4 is high, and free T3 is low it can indicate under conversion of T4 to T3, OR the T4 is converting to RT3. Good luck with getting tested! It can make all the difference to understanding your particular thyroid issue. Best wishes, Louise O’Connor

  7. Hi Louise,
    Thank you for the amazing info. I have elevated rt3 at 415pmol/l
    My free t3 is 5 pmol/l
    And ft4 is 18pmol/l
    I just used your ratio calculator and that makes me at the very low end at 1.20.
    I have started taking a thyroid supplement with zinc, iodine and selenium and nearly straight away I felt my brain fog had lifted for once. I’m also the same as an above comment where I have a high ferritin level which I am working at to get down. Am I on the right path or should I be looking at what my cortisol is up to as well.
    Thank you for you amazing work it has been so very helpful.

    • Louise O'Connor says:

      Hello Jade, great to hear my post on RT3 has been so helpful. High ferritin is often associated with hypothyroidism and there are a few reasons why. The best info I have seen on this topic is over on Stop The Thyroid Madness blog. I recommend investigating if you are dealing with some type of chronic infection, or toxicity issue. A functional medicine doctor or Naturopath are best at taking a comprehensive medical history and then investigating root causes of illness. Did you know I developed ThyroSynergy thyroid health supplement? It contains iodine, zinc, selenium, and B-vitamins all in one capsule. Best wishes, Louise O’Connor. Here is link to view contents at end of the page:

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