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Thyroid UK
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Hi all, new to this so bear with me! Have been taking levothyroxine for 3 years now and my symptoms haven't improved at all. So pleased that I found this site but have just read about not taking thyroxine before a blood test...why is this? Can it change your results?

14 Replies

Yes, it can give the impression that your treatment is adequate when it may not be. I believe the idea is that if you take your meds shortly before your test there will be more in your system. I don't think I've ever met a doctor who subscribes to this point of view.

I know it gets said a lot here, but it really is a very good idea to get a copy of your test results and post them here. Someone will be able to explain what is going on and if there is any way you can improve on your current situation.


Dr Weetman subscribes to this point of view... It was him that explained it, under oath, when he was a witness against Dr Skinner at the first hearing of the GMC. The transcripts are on tpauk aand its day 3 or 4 if you want to check it out.

Xx. g


galathea, can you clarify please? What was the point Dr W was trying to make in reference to Dr S?

Whenever I've asked about it they say it doesn't matter when you take your levo/have blood draw, even the private gp who is very pro-supplement and diagnosed my adrenal problems said it wasn't an issue. But if it is that slow-acting then, logically, not taking it shouldn't make a difference either. I never take my meds before a test.


Its day 4 page 13 of the transcripts. Here is what prof Weetman actually said....

" A: The problem with using free T4 measurements if a patient is taking thyroxine is that the level fluctuate after taking thyroxine treatment. Therefore, within the few hours after ingestion there can be a ten or fifteen per cent level difference in level compared to twelve to twenty four hours after ingestion. The second problem which is frequently encountered by endocrinologists is that the patients may not adhere to their treatment very strictly and may remember to take a tablet before a blood........"


Hi nicky, why have they not made dose changes to help you? Is it because they think your tests look normal? Or have they tried to increase your dose and for some reason it doesn't help.

We try to find your optimal dose of levo which hopefuly are a TSH around 1.0 and FT4 in the higher part of the range. Have they ever offered to do an FT3 test? This is the one that reveals how much active hormone is working for you and should also be higher in the range.

To make everything work together you need to have good levels of iron, folate, ferritin and B12. Do you know or have ever tested those?

All these things are necessary to help you feel good. It is difficult since the NHS would rather ignore a lot of the above but there may be ways of doing so.

1 like

Welcome to the forum. Lots of good advice already given but if you post your results and ask for help/comments it's easier I think, for you to understand what is happening when they are your results and you can correlate this to how you are feeling. Then hopefully when your dose is adjusted you will see the change in your next results and hopefully improvement in your symptoms. Even if your results look good for TSH and FT4 then without your FT3 results it's difficult to be sure that your body in converting the FT4 to the active FT3 which your body may be crying out for! Many doctors seem to think it happens by magic but there are ways that can help that along. First step though is to post your results and the ranges as the ranges can differ from lab to lab.


If you take levothyroxine in the 24 hours before a test you will land up with the doctors reducing your dosage because it gives a false reading

Since you have been taking levo for 3 yrs and not feeling any better I suggest you request urgently tests for

Free T4

Free T3




vit D3

the last 4 MUST ALL BE halfway up in their ranges otherwise your body simply cannot use the levothyroxine and you wont improve

your TSH should be below 1

your free T4 a

and Free T3 should be in the UPPER quadrant of their ranges

Always get a print out of all results and NEVER accept doctors saying " normal "


Very helpful advice. I currently take 50mcg of levothyroxine and 10mcg of T3 replacement/liothyronine divided into 4 doses taken at six hourly intervals through the day. I've tried everything and this is only way I can take T3. Before my next blood tests I will not take levothyroxine for 24 hours but what about the T3? I think I would feel pretty bad if I did not take that for 24 hours but would do it if that would give more accurate results. What is the best advice on this?


NO thyroid meds whatever in the 24 hours before a test

Have your




vit D3

been tested because they are just as vital

you might also be better on NDT many Hashis patients are


How do I get a copy of the results? Can I just ask at reception for them or do I need to see the doctor as trying to get an appointment is a nightmare! Since 2011 I have had so many blood tests but mainly because the Dr thought I was menopausal and didn't want me to go on hrt too young..I'm 41.. I last had a blood test in November that confirmed I was definitely not menopausal. I sat there with my head in my hands and said 'well what IS wrong with me then' to which my dr came up with fibromyalgia and repeat bloods in 3 months! I showed her an article that said about testing for t4 & t3 and she said she had and that it was normal but I don't know what the figures were. I take my levothyroxine at about 11pm and never knew about not taking it before a blood test and the Dr has never said about not taking it. In 2011 I was a size 12-14 and had loads of energy but am now a size 18 and I would sleep all day if I could!


It definitely sounds as though you are undermedicated. How much Levothyroxine are you taking? When you have a blood test you really need to have it done first thing in the morning. Thyroid hormone levels fluctuate during the day but are lowest in the early hours so to get the results you need for an increase in medication the test needs to be done first thing.

As for the results - the receptionist should be able to give you a printout or at least tell you verbally. It's your body so you have a right to the results as I understand it.

Of course there is always the option of getting some more medication yourself - a lot of people on this forum either completely self medicate because Levothyroxine doesn't suit them, or top up what the doctor gives them with bought-in meds - either 'food supplements' like Thyro Gold, natural dessicated thyroid (NDT) like Thyroid-S, or like me, extra thyroxine bought on holiday in Turkey where you don't need a prescription and it's very cheap.

Doctors are prone to undermedicate their patients due to ignorance (they think a TSH reading within the very wide 'normal' range will make people feel well) or due to defensive medicine - they could get sued if thy prescribe too much medication and send someone hyper and give them a heart attack, whereas keeping someone hypo for years means they haven't got the energy to complain, and anyway you can tell them they have fibromyalgia, obesity, ME, CFS, hypochondria .......


I'm on 100 mmgms. Never thought about self medicating and the thought is a bit scary tbh. I wouldn't even know where to start! I've got seriously bad brain fog which is so frustrating as my memory has always been really good and my vision seems to have deteriorated over the last year....could that be down to my thyroid? I'm now taking folic acid too as my last blood test showed I'd got low folate.


Yes so it says on the site recently, but I haven,t found this to be the case personally, but its worth a try in your own case. Three years is an awful long time to go on without any change in your symptoms. How many visits did you make to your GP initially, and how many separate blood tests have you had in the last 3 years? The normal rule is visit GP who sends you for blood tests, prescribes you 25mcg if Hypo. Return to GP in 6 weeks, sends you for another set of bloods and this goes on until GP decides you are on the right dosage of Levo for you purely on test results. If you don,t feel any better, more or less straight away ie or maybe 3-4weeks in some cases then you are not on a high enough dose or your case is not just a straight forward case of Hypothyroid. Visit your GP again asap and get things sorted out as you should not still be suffering the same symptoms if your meds are right. If you do not get any joy, change your GP.

Good Luck


I've become a regular visitor there over the past few years! I switched doctors last summer as I didn't feel I was getting anywhere with the doctor I had. It was always the same thing...all of your levels are normal. I could keep on till I was blue in the face so I changed my doctor. This one has been a lot better and keeps saying that we'll get to the bottom of what's wrong but it just takes time. My next blood test is due in the middle of Feb but am thinking about popping in to see if I can get a copy of my results so I can post them on here for opinions.


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