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Thyroid UK
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Anyone know how to get thyroxine tablets lab tested?

Has anyone sent thyroxine tablets for lab analysis to determine the potency?

I have been healthy on liquid thyroxine for a few years, after being ill for 20 years on tablets. New GP surgery wants me to change back to tablets in order to save money. I will be allowed a little liquid to top up from 100mcg to my 120mcg. I want to get each batch of tablets lab tested, so I know the real potency, and can top up to an accurate dose. Accuracy is everything for me.

13 Replies

Was it the fillers in the tablets that made you ill? If so I would refuse to go back on them after being well on liquid Levo for years.

1 like

Hi SeasideSusie and thanks for your quick reply. No, I have no reason to think that fillers were a problem. Tablets vary in potency, and I can't cope with that. When I insisted on changing to liquid, it was the time when some were sub-standard for months, and like many people then, I was destabilized. I also changed to twice per day, which is very important to me.

The liquid is over £10 per day. That is the issue.


OK, it probably makes it more difficult then. I'm afraid I have no idea how to get tablets tested or even the cost if it was possible. I wonder if diogenes or helvella might know a bit more?


Tablets are tested according to a set formula regulated for every producer. They take standard conditions, probably no food, and use either animals or human volunteers to test the rate at which T4 enters their systems. This is all very well, but it doesn't take into account food competition, and stomach acid variation and intestinal absorption capability differences. There is a major disjoint between the formal regulatory demands and real life.


Laboratory testing is one thing...

Remember the Teva "old formulation" that had its licence withdrawn at the start of 2013? That actually contained the claimed amount of levothyroxine in at least some lab tests.

Trouble was, that dose was not being delivered. I think the dextrin ingredient was holding on to the levothyroxine.


Hi Helvella: I didn't spot your post - sorry. OH YES! I remember the 2013 Teva upset very well indeed! That is what destabilized me, and led eventually to the revelation that my many years of illness had been thyroidal, despite treatment, and not due to M.E.. What happened with thyroxine tablets in this Country that year was absolutely dreadful, but without that upset I would still be disabled today, and still blaming M.E. I could not have moved on.

Do you have more detail on the lab results for Teva when their production was in trouble? - the run-up to losing their licence. I hadn't read about a possible problem with dextrin.

What I feel is that I would be willing to try going back on to Teva tablets for my 100mcg. if, and only if, I could get a lab to test a pack each time and tell me the actual potency, so that I could top up accurately to my 120mcg. I am not willing to downgrade to variable medication, because that would mean variable health with long periods of disability - life as I now know it would stop.


Have a look at this report:


As I said before, though, those Teva tablets could well have sailed through laboratory testing. The only test that matters is how well it works for you. No lab test - though it includes dissolution and many other factors - will prove that a tablet will deliver a specific amount to you.


First of all I would refuse to change my medication. Especially after suffering for twenty years on levothyroxine.

I would speak to my MP as they should not refuse your plea to continue on a thyroid hormone replacement that makes you well. I will add lynmynott in and she may have some good suggestions.

As far as I know they were directed to remove T3 but you are on liquid levo.


Thank you, Shaws, for that fighting response! What happened, back in Feb, is that I was SUMMONED to see a particular GP when my blood results came in. Actually, the bloods were as normal for me; there was nothing wrong, but I was told I must take less. I told a brief version of my case history, and got her to accept a drop of just 4mcg. Then the bombshell that she wanted me to also swap to pills. Well, I kind of went into shock and struggled to communicate. I expressed that I was terrified of being put back in the illness state I'd spent 20 years in.

The worst was over the following weeks: I got silly distressed and made myself ill. I'd always said to myself I would NEVER go back on tablets. It had been a horrible appointment as the doctor was running an hour late and needed me to be quick and undemanding! She was already stressed up and didn't handle it right, and I felt accused.

I wrote to the GP, putting my case strongly, and they seem to have discussed my case in a meeting and decided to allow me another 6 months of liquid thyroxine. In that space I am trying to learn about my options.

The cost of the liquid is huge - about the same as the State paid me to survive when ill all those years! I think it is a much more positive way to spend money on me, as I get a life!!!

I don't have a problem with tablets as such, it is the variability - not knowing what dose you are really taking, and the potential unprescribed dosage changes of up to 15% each time you collect a prescription. I have benefitted hugely from accurate meds.


When we've been very, very ill, either being undiagnosed or given replacements which make you feel worse, we are positive we do not want change because it is not our fault they have now restricted everyone to levothyroxine. Surely a False Way of treating as the patient becomes very ill, may not be able to work or even have a decent life.

We didn't ask for our bodies to react and it may well do to a synthetic thyroid hormone.

I hope you are able to get a resolution. If you are well - why change on a whim of some 'supposed' to be experts.


It’s generic prescribing that’s causing you the problem then? Can’t they make an exception to make sure you always get the same tablets - if you end up giving up your liquid, at is. Maybe you can make a case - can you see a different GP. Perhaps keep a low profile? Maybe they’ll forget? Good luck x


Thank you Aurealis, and everyone. If I were on tablets, I would make sure to always have the same make. (In the past I didn't know about that). It would be TEVA because Mercury is a totally unethical company, and Actavis may be the worst of the three - I had a dangerously bad pack of theirs some years ago, and my pharmacy where I lived until recently stopped stocking Actavis because they had so many complaints about them.

What happens if you absolutely refuse to change your medicine? It seems to me that you could be between a rock and a hard place - take the new stuff, or die: your choice!!! Has anyone here tried absolute refusal to change?


Maybe have a meltdown and GP may continue liquid on stress grounds - yours or his, whichever! :)


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