Being Hypothyroid with a Normal TSH

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Have you been told that your TSH is ‘normal’, ‘fine’, ‘OK’,  or ‘in range’, and still have hypothyroid symptoms?

You could be on thyroid medication or not, and have a TSH as described above, and still be hypothyroid.

You could be hypothyroid at a cellular level, due to conversion problems of T4 into T3.

The Difference in Thyroid Hormones 

T4 is reported to be about 90% of what the thyroid gland produces, with around 9% being T3. Some of the T4 also converts in to T3, or at least it should, and adequate levels of both is what’s needed to help us feel well and carry out all our usual bodily functions and processes.

What is a Conversion Problem?

An inability to properly convert T4 to T3 is common among thyroid patients and can result in a fluctuating TSH or a TSH that is ‘in range’ and a low Free T3

Many patients have an in-range TSH, but when they actually check their Free T3 and Free T4, they show that the T4 is not converting to T3, with a low Free T3 level.

This can be caused by an enzyme called iodothyronine deiodinase that is either deficient or not compatible for some people. The enzyme iodothyronine deiodinase is important in the activation and deactivation of thyroid hormones. T4 is converted into T3 by deiodinase activity.

Another possibility for conversion issues is adrenal dysfunction (although it is more accurately referred to as hypothalamic-pituitary axis dysfunction), or other vitamin deficiencies such as iron or seleniumPoor gut health can also be a contributor.

By addressing these, you may fix the conversion problem, but many other people simply have a problem converting and don’t know why. But it’s a big reason as to why T3 and NDT medication can work better for a lot of patients, instead of T4-only meds like Levothyroxine or Synthroid, because it gives them direct T3, so they don’t have to rely on their body to convert it.

Test Results 

The optimal TSH level is well reported, but many doctors are still using an out-dated reference range going anywhere up to 6 or even 10, and feel that anyone falling within this huge range is adequately managed, even giving the diagnoses of ‘borderline’ or ‘subclinical’ hypothyroidism.

However, if your hypothyroidism is not properly managed, it puts you at risk of developing other health conditions, whether thyroid hormone levels are too high or too low.

If your TSH is within the recommended optimal range and you still don’t feel well, you should ensure that your Free T3 and Free T4 also sit in the optimal places in range. Other key tests, like adrenal function, are explained here.

Have you been told your test results are ‘normal’, yet still experience ongoing symptoms?

You can click on the hyperlinks in the above post to learn more and see references to information given.

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Written by Rachel, The Invisible Hypothyroidism

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