WHY AM I SO SENSITIVE TO t4

[fiftyone]

If T4 (thyroxine) is an inert substance which has to be turned into T3 before it can be used by the body, why am I so immediately sensitive to my T4 dose? (My T3 has been steady for many, many months at 5.7) As soon as my thyroxine is reduced by 25mcg a day, I experience within a couple of days, pulsatile tinnitus and disturbed sleep. As soon as I put the dose up again, within a couple of days the pulsatile tinnitus has faded a way and I'm sleeping properly. Changes in dose are expected to take full effect after six weeks. I react within a couple of days.By two weeks of T4 dose change I'm either feeling hugely better or hugely worse . . .never mind six weeks.

[helbell]

Hi fiftyone,

I know it doesn't add up with the science but I also experience a difference in symptoms very quickly against changes in dose. Plus, I can feel my daily dose kicking in within two hours of taking it. Look forward to more replies.

[hobbycat]

Ah fiftyone, kinda good to see your message actually. It seems we are not alone. A couple of years ago I was taking alternate daily doses of 100mcg/125mcg levo. Each day I felt different - even my sons and boyfriend would know if I was on a 125 day or 100 day. My mood, energy and cognition would be so much better on a 125 day and I could stay up later and not be so cold in the evenings. I took this info to a private Endo who completely pooh pooh my data and experience. So, hooray, there is someone else who experiences the same. It was as though the extra 25 levo released some more T3 for me though I have yet to find the medical answer - and perhaps there isn’t one. I have now added T3 and I feel I am particularly sensitive to the tiniest of changes to that too.

[m7-cola in reply to hobbycat]

I too feel different on days when I have my 150mcg rather than 100mcg tablet. Because there’s no 125mcg available in my brand I alternate.

[Andyb1205 in reply to m7-cola]

Count me in too! My guess is that our bodies are literally starving for thyroid hormones so they’re eaten up fast.

[fiftyone in reply to Andyb1205]

Yes. I wondered whether, if our body needs it, we convert and use up the hormone very quickly. Other times, if our body doesn't need so much, it stays as T4 in the bloodstream. This might explain why my T4 level goes up and down even though I'm on the same dose. Are we 'super-fast, super-sensitive converters'??

[jgelliss in reply to hobbycat]

Learning to trust what I feel was the first step to my Wellbeing . Advocating for myself was the second lesson for me .

[Hidden]

The only thing that crosses my mind is perhaps your body is converting most of the T4 you take for your body's needs, so as soon as you drop the amount, there's simply less there to convert so you feel it pretty quickly. Just a random thought!

[adin]

I've the same problems, after 2 hours I feel anxious, because of that I can not think clearly, my sight is getting sharper but in the afternoon the effect is opposite. All it seems to be related to reactive hypoglycemia.

[Murphysmum]

I find the same! I was recently advised to increase 25mcg and in the morning following that dose ( I take my levo at night), i was so hot, my tinnitus had returned (and did for around ten days) and my thyroid is slightly swollen (so it’s uncomofrtable when I turn my head to the side but otherwise not really noticeable).

I have poo-pooed a friend in the past, who says she can increase or decrease her dose to suit how she feels, but now I am finding the same! I feel better already on this dose, although as my symptoms tend to vary over the month, I will give it 8 weeks or so before I decide whether it’s actually working or not!

[jgelliss in reply to Murphysmum]

I heard that some do great splitting their T4 during the day . They feel much more energized . My friend splits her T-4 dose first thing in the morning with some of her T3 . And her second dose at about 4PM with some more T3 . And tells me her Dr looks at her with Why kind of a look . But she says it works for her . And the Dr's told her as long as she feels better for it he has no objections . It's all about trial and error . Don't be afraid to try different hours . Small tweaks like that can make the difference . Who cares the look you get from others . As long as you know it works for you .

[greygoose]

The truth is that no-one really know what T4 does, if it's just a storage hormone or if it has other functions. Some people cannot tolerate T4 at all. So, until more research is done - don't hold your breath! - we just have to adapt to the way we personally react to T4 and dose accordingly.

[Aurealis]

I’m the same. In the days when I took thyroxine I knew for certain by day 3 following a dose change if I’d done the right thing. It may take 6 weeks for the blood tests to stabilise following a dose change but you can feel well much sooner. Perhaps you currently convert very well x

[helvella Administrator Thyroid UK in reply to Aurealis]

6 weeks for the blood tests to stabilise

That has always been my interpretation. Some people seem not to notice even large changes for a long time. Others notice even small changes almost immediately.

FT4 and FT3 blood tests tend to change quite quickly but the final stabilisation of those and TSH can take weeks.

Contrary to almost everything you read, I have watched someone take a modest dose of levothyroxine and start to feel better within about fifteen minutes.

I found that 100 micrograms was too little; 125 micrograms too much. But I did not like alternating 100 and 125 day by day. Felt much better taking 112.5 every day. Explanation? I really do not have one. I always feel surprised by the lack of effect so many report!

[Aurealis in reply to helvella]

I did find that alternating doses sometimes took a bit longer to feel right, but not much more. I understand the fifteen minutes too as it used to put the colour back in my colour vision, I could watch the colour re-appear.

[jgelliss in reply to helvella]

helvella

It does not surprise me that you don't like to alternate between doss . I don't like either . And I don't know why myself . Even though I prepack my doses in to daily trays 2-3 weeks worth . Do you also take any T3 to your 112mcg T4 ?

[helvella Administrator Thyroid UK in reply to jgelliss]

No T3.

[jgelliss in reply to helvella]

Thank You helvella . Your one of the Lucky ones that does Great On T-4 Only . That's a Blessing . Do you have Hashi ?

[helvella Administrator Thyroid UK in reply to jgelliss]

Not as far as I know!

[jgelliss in reply to helvella]

helvella , You reminded me that after my RAI I was totally off T-4 for weeks and felt awful . I was on the short acting Cytomel (T-3) and I remember having every hypo symptom you can possibly think of . As soon as I resumed my first dose of T-4 within hours later I felt some Positive difference . It took me within three days to feel that I was coming back to myself . Even today I need a small dose of NDT for my T3 mix to my higher dose T-4 . It calms my palpitations . On T-4 Only my heart was not getting the T-3 it needs .

[Hidden]

It's not just a prohormone - it has direct use in parts of the body, from my understanding. I'm not sure how that adds up to people who are well on T3 alone! But my understanding is that it is not just an inert substance, and that's logical too - if the body only need T3, and can obviously make at least some of its own directly, it makes no sense that the body makes mostly T4.

[helvella Administrator Thyroid UK in reply to Hidden]

Whilst I agree that T4 likely has effects which mean it is not just an inert substance, I am not sure I agree with your argument!

The production of, mostly, T4 could be viewed as a way of distributing thyroid hormone around the body safely. That is, if T4 has no effect, each cell that wants thyroid hormone could pick T4 up from the bloodstream and convert as it needs.

If there were higher levels of T3 in the bloodstream, the cells might have little control over the amount of T3 they receive. You could also imagine that blood far from the thyroid might be somewhat depleted in T3 by the time it reaches them.

Another way in which T4 might have an impact is that when converted inside cells, it releases iodine. Direct T3 would not release that iodine atom. Therefore T4 allows the possibility of safe distribution of low levels of iodine directly into cells.

This is all speculation! But it does suggest to me that T4 is important in some ways.

[Hidden in reply to helvella]

Interesting thoughts, but yes, we’ve both come to the same thought that t4 is important

[jgelliss in reply to helvella]

helvella ,

You Make Great Points . Personally and I'm speaking for myself I need T4 for my brain juices . If my T4 is low I feel that my concentration is just Not the same . Some find that the T4 helps them with weight loss too . I feel that for me personally T-4 acts like a diuretic .