T4 or T3

[fiftyone]

Just had a chat with a GP. He says that the medical profession believes overmedicating on T4 can damage the heart. I suggested that T4 has first to be converted to T3 before it becomes active and therefore the T3 measurement will determine whether the heart is in danger. He insisted it was the T4 level which was important. Which is correct?

[Min789]

Yes I would like to know the answer to that too.

[Angel_of_the_North]

You are. And anyway, you need to define overmedication. A low TSH and slightly over range free T4 from medication (as opposed to hyperthyroidism) haven't been associated with heart problems, but low T3 has. Give GP the Dr Toft article.

[Min789 in reply to Angel_of_the_North]

Hi Angel of the North could you give me a link to Dr Tofts article stating low T3 is assosciated with heart problems?

[Angel_of_the_North in reply to Min789]

The Dr Toft article is the one that says it is OK to have a suppressed TSH and over range free T4

[Min789 in reply to Angel_of_the_North]

Yes I have given a copy of that article to my gp. Don't think he's very confident to go with anything different to what he knows unfortunately.

[fiftyone in reply to Min789]

I get the impression that GPs are guided by their own associations and official recommendations and don't go outside those boundaries.

[Angel_of_the_North in reply to Min789]

These are all related to low T3 and heart problems: heart.org/en/news/2018/12/1...

ahajournals.org/doi/full/10...

ncbi.nlm.nih.gov/pmc/articl...

ncbi.nlm.nih.gov/pmc/articl...

healio.com/endocrinology/th...

dicardiology.com/article/de...

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