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What is Reverse T3, and why you need to get it tested.

Reverse T3 or rT3, is an inactive metabolite of T3 and is one of THE most important measurements of thyroid function – as stated by the Journal of Clinical Endocrinology, but is dismissed by many doctors and endocrinologists.

This is how it works….the thyroid produces two hormones, mostly T4 and a very small amount of T3. T4 must be converted to T3. T3 is the active thyroid hormone that is used by our cells for energy and metabolism. T3, in certain situations can be shunted off to rT3 which then goes to the cells and blocks the thyroid effect of energy and metabolism.

If you have a high reverse T3, it is like an anti-thyroid effect and the thyroid cannot function well. rT3 is like the hibernation hormone, it shuts our metabolism and energy down which equals – fatigue, weight gain, brain fog, and constipation….everything slows down.

Why does our active T3 go off to rT3??

T3 goes to rT3 in the following conditions:

  • Adrenal gland dysfunction – both high or low cortisol levels affects thyroid functioning

  • Chronic stress

  • Prolonged illness/infections

  • Inflammation

  • Heavy Metal toxicity – BPA, mould, lead, mercury, cadmium exposure

  • Low nutrients - iron, low B6, low B12, low selenium , low vitamin D

  • Yoyo dieting or fasting

  • High oestrogen

  • MTHFR gene

When rT3 is high, it binds to our cells and our healthy T3 cannot get into the cells because the rT3 blocks it from getting in and having an active effect. This is called “tissue resistance” which is a common anti-thyroid condition. You can have “normal” thyroid levels on your blood tests, (TSH, T4 and T3), but rT3 may be high blocking T3 from getting into the cell. This is why Rt3 should be tested every time you have your thyroid tested. So you can take all the thyroid medication you like, but it will not make you feel better, and may actually make you feel worse, because it all goes off into rT3 instead of being converted to active T3.

When T3 cannot get into the cell you it causes low T3 symptoms such as fatigue, brain fog, weight gain, indigestion, bloating, depression and many others.

I see this a lot in clinic….. Hypothyroidism is diagnosed and thyroxine or similar is given, but it doesn’t make a difference. The thyroid symptoms continue and/or get worse and the Dr prescribes a higher dose of medication. This makes the patient no better or actually worse! Sound familiar??

Rather than giving more and more medication, we need to make the cells function properly and be more receptive to T3. We do this by treating the above conditions, such as chronic stress, high oestrogen levels, infections, inflammation and nutritional deficiencies.

Knowing your unique thyroid causes and triggers such as chronic stress , inflammation, heavy metals load, and having the correct testing including rT3, goes a long way to supporting your thyroid health.

If you want to know the right testing for your thyroid and how to treat your unique triggers and causes of your thyroid condition, check out The Thyroid Recovery Program HERE.


Tuesday 9:00am - 5:00pm 

Wednesday 9:00am - 5:00pm 

Thursday 9:00am - 5:00pm

Phone: 0417 945 333


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