1. It should be both but also symptoms. However it can sometimes take up to 3 months on a stable dose, and the “right dose” for some some to fully resolve. (Some symptoms resolve more quickly.)
2. It can vary. It’s partly as t4 has a long half life, between 7-10 days. So it takes about 4-6 weeks to properly reach a stable level, though a decent amount builds within 2 weeks. Hence a re test and any necessary tweaking.
However, thyroids can continue to deteriorate so it can take frequent monitoring. It’s really useful to record results and note symptoms. Increased strength, less constipation, able to stay awake all day, better memory, etc.
The best thing a patient can do is take thyroxine carefully and correctly to give a stable baseline. (Something I still have to revisit after 20+ years!)
3. Yes. A day or two, not really. Two weeks, yes, considerably. Missing one day a week could equal a full 25 or more drop in daily dosage. My Gp said that her (Gp!) sister in law took hers with coffee every morning. Stopping that and switching to water resulted in being able to drop 1/4 of her thyroxine.
4. Complex as someone else may answer better. There was a good post recently that said some tsh is helpful too to many. Something to do with homeostasis.
However, t3 and t4 vary a lot during the day in both healthy patients and thyroid patients. There are even slight seasonal variations in tsh. And thyroid patients vary too. You have to look at the whole picture including symptoms. And also look at things like vit d, b12 and folate and also ferritin. These things can both help conversion or deficiencies can give similar symptoms.
5. Consistency is key. I never used to fast as I don’t know and I do have a cup of tea at least. Morning is more important in my opinion and not taking thyroxine before hand, as t4 peaks in blood a couple of hours afterwards. Someone else may have a better answer.
Stop anything with biotin (a b vitamin) in a week before the test.
6. No, the Gp wouldn’t unless a specific reason. Gps very rarely take antibodies. I had it 20+ years ago.
Yes symptoms play a key role in determining the over all improvement .Sorry i forgot that part.
will make note of it.,and observe.
I had an understanding earlier that any thyroid test is always to be done on empty stomach only,
but an hospital staff( whom i had enquired )clarified reg that,said fasting not necessary for free t4,freet3 ,tsh but most labs insist fasting for total t4,total t3.
It doesn’t hurt to fast if you can. Consistency is key.
If you’re newly diagnosed I’d actually read all the British thyroid foundation leaflets and also the BMA understanding thyroid book by A Toft (Amazon.)
A lot of the finer details around testing and t3 etc are complex and it’s best to work with the Gp to get a good tsh and balance first, see how you are, before exploring other things. Your thinking may be a bit fuzzy at the moment till treatment is good.
Definitely ask if they’ve tested ferritin, vit d and b12 / folate and what the levels are.
Eat a well rounded diet with meat, dairy and white fish, fruit and veg and good carbs.
Any fish is good, white has more iodine and although thyroxine actually has iodine so actually it’s not as important when on thyroxine, it’s helpful for homeostasis. Selenium helps conversion too.
There’s some fact sheets/ pages on the btf website around diet and those foods.
I would definitely consider getting a good vegan multivitamin with rda iodine and selenium, b12 and iron will also be helpful. There are some b complexes often recommended here, b12 and 1 and 2 are also v supportive to help with all things thyroid. (Thorne basic b is one.)
Avoid iodine from kelp, unfortunately many do have that. Too much is bad and it’s both poorly absorbed from kelp as well as risk if heavy metals. I think the vegan society recommended one.
I don’t know if you are male or female, but just for info there are risks to pregnancies with a poorly controlled thyroid and iodine is v important for developing baby.
As stated here, extra iodine isn’t really needed when on a full dose of thyroxine (50 is low) but as you eat so little that contains iodine it might be helpful/ won’t hurt.
1. 50 mcg is a "starter dose" and is very likely to need increasing. Your GP will concentrate on TSH because that's what s/he was told in their half hour of thyroid training, but what your thyroid hormones are doing is more important, for a variety of reasons, so just testing TSH isn't enough.
2. As long as it takes ... you should only increase slowly, as it takes the body a while to adjust to dose increases. Bloods should be re-tested every 6 - 8 weeks and dose increased by 25 mcg a day until TSH is less than 2, probably less than 1; free T4 is in the top third of range and - crucially - you feel well. You should then re-test annually, as things change
3. Yes - dramatically. Levo is a "storage" hormone and so has a much longer half-life than lio (T3 meds) - but skipping a few days before a test will still reduce your free T4 result. But it takes MUCH longer to affect your TSH result.
4. Total T3 and T4 aren't a useful measure of anything, It's the free T4 and T3 which are important, as this is what gets into your cells. Free T3 is the most important measurement of all as this shows how much active hormone your body is getting. But it is the test done least.
5. They probably do - but not eating or drinking for a good hour after taking your thyroid meds is the best way of absorbing them properly. I have seen on a different site that up to 70% of lio is NOT absorbed if you eat or drink straight afterwards - the figure is lower for levo but still quite high. In terms of testing, for TSH the key thing is having an early morning blood test as this is when TSH is highest and (see above) most GPs are obsessed with TSH ... Leaving the "approved" gap of 24 hours from previous dose of levo and 8 - 12 hours of lio means that you (a) are consistent in your measurements and (b) have a good representative level of hormone in your blood - rather than being assessed on the basis of a "spike". Doing a fasting test means you can take your next dose straight afterwards (as you shouldn't take your meds within 2 hours of eating of drinking either). In terms of taking other meds, you should leave between 2 and 4 hours between your levo and other medication (not sprays), to ensure they are all properly absorbed. Stop anything with biotin in a week before a blood test to ensure it doesn't interfere with the test
6. Testing antibodies will show if the reason you are hypo is Hashimoto's. This is the biggest single cause. If a test shows positive for antibodies (ie over-range) this means you have Hashi's. You don't then need to re-test - Hashi's doesn't go away and your antibodies will go up and down as they see fit regardless of anything you might do or your level of meds. But it's quite useful to know, as many Hashi's people find it helpful to go gluten-free. A single negative test doesn't necessarily mean you don't have Hashi's as it may just be that your antibodies were low then and then go up later. So you may want to do a repeat test later if the first one is negative.
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