t3 conversion

[Dizzy444]

Good morning, I hope everyone has had a nice Christmas. I’m trying to get my head around this subject and I’m struggling to understand it. So if you are a poor converter of t4 medication, would it be the case that you were a poor converter of the natural t4 produced by your thyroid prior to becoming hypo. Or is it the case that the thyroid gland produces both t3 and t4 when it’s healthy. I hope I’m making sense, my brain seems to be very foggy at the moment.

[SeasideSusie Remembering]

Dizzy444

Or is it the case that the thyroid gland produces both t3 and t4 when it’s healthy.

The thyroid gland produces T4 and some T3. Other organs in the body convert T4 into T3 by deiodination, eg liver and kidneys. Deiodination is where an iodine molecule is removed from the hormone T4 so converting it to T3.

[Dizzy444 in reply to SeasideSusie]

Thank you for replying, so is it just the synthetic form of t4 that some people don’t convert ?

[helvella Administrator Thyroid UK in reply to Dizzy444]

Once T4 is in your blood stream, there is no difference between what you produce yourself, what is made in a factory, or what comes from another animal.

There is discussion about whether any T4 can be used directly, but pretty much all T4 needs to be converted to T3 in order to be active and usable within cells.

[Dizzy444 in reply to helvella]

Thank you, I’m going to see if I can get t3 prescribed. I see no point in doing a gene test as I was fit and healthy before my diagnosis. I just need to do another vitamin check to make sure these are adequate.

[helvella Administrator Thyroid UK in reply to Dizzy444]

Before diagnosis, your body had developed with whatever genetic makeup it had. It will, so far as it was able, have adapted to those genes.

Further, with a healthy thyroid, some T3 will be made in your thyroid gland, and some T4 will have been converted to T3 by your thyroid gland.

If your ability to make T4 and T3, and to convert T4 to T3 in your thyroid, have ALL been impaired by thyroid disorder, you might not be able to convert sufficiently.

[SlowDragon Administrator]

For good conversion of Ft4 to Ft3 we need GOOD vitamin levels

Being under medicated for thyroid and on too low a dose levothyroxine results in low vitamin levels

Also lower vitamin levels are more common as we get older

Conversion of Ft4 to Ft3 is often worse after menopause, though no one quite seems to know why

ESSENTIAL to test vitamin D, folate, B12 and ferritin at least annually

[Dizzy444 in reply to SlowDragon]

Thank you for the reply I’m gradually getting my head around this

[jimh111]

A healthy thyroid produces a little T3, about 7 mcg on aveage but this can increase substantially at the thyroid starts to fail and fT4 falls pushing up TSH.

Sometimes if TSH has been supressed for a long time TSH can remain low and this reduces conversion rates. Looking at some of your previous posts this doesn't seem to apply to you. It is best to have a little liothyronine for many reasons including it being closer to how the healthy thyroid works.

[Dizzy444 in reply to jimh111]

thank you for replying, I was thinking about those who have the faulty gene that hinders conversion, presumably the faulty gene is present at birth so would have caused lifelong problems

[jimh111 in reply to Dizzy444]

The rs225014 polymorphism on the DIO2 gene reduces type-2 deiodinase (T4 to T3 conversion) a little. This can become a minor problem when people's thyroid packs in, they perform slightly worse in cognitive tests and respond to the addition of a little liothyronine. Prior to hypothyroidism there is nothing to suggest they are worse off thyroidwise than people without the polymorphism - because their thyroid supplies some T3. There are studies that show this polymorphism may be associated with other disorders, I haven't looked into this.

There are other causes of reduced conversion, such as reduced secretion of TSH (for given fT3, fT4 levels) or TSH of reduced bioactivity. There is little research in this area but in my view it is a major cause of poor conversion and leads to severe signs and symptoms of hypothyroidism.

[Dizzy444 in reply to jimh111]

Again thank you for the very interesting reply, much to think about. Sometimes I feel the more I learn the less I know. It seems to me that thyroid disease is the poor relation in regards to medical research

[arTistapple in reply to Dizzy444]

If this is the case the patient would probably know no different. What would they compare it against? People can only experience their own lives; no matter what their observations or knowledge etc. Mostly (thankfully maybe) dreadful disease patterns/symptoms do not overtly show up until later in life. We know there are certain factors which contribute to ill health and not everyone predisposed to diseases genetically, necessarily develop them. In my case I think I knew there was something wrong way before it was diagnosed (and I mean decades) but symptoms were considered ‘normal’. Even when symptoms were clearly outwith ‘normal’ they were not related to hypothyroidism. The symptoms just gradually increased relentlessly year after year. The guilt alone, associated with not being a ‘proper person’ (hypochondriac - I have even mistaken the word for hypothyroid when describing my situation) carried for many years has been incredible. I think people with thyroid issues are very badly served. It is so common that instead of being the last diagnosis to be considered, it should be considered up front and a genuinely caring system of health would monitor it annually. Lives would be saved. Quality of lives would be saved. AND cheap testing of TSH, T4 and T3 would save the NHS an absolute fortune. Oh and properly educated medics would also be helpful!

[Dizzy444 in reply to arTistapple]

I agree, many people have problems years before being diagnosed and I’m sad to say that in the present climate I can’t see things improving. One thing that really annoys me is that gps should make the effort to be more informed with any common illnesses, there’s no excuse for ignorance. I know they are under pressure, and often overworked but we trust them with our health and things need to change.

[arTistapple]

Totally agree!