As the title says I was wondering if it is best to take thyroid meds before or after my thyroid blood test. I have always taken it after but at my last test a month ago I took it before and my TSH reading came back 0.9 having previously been 12 a month before (I took my meds after that one). At my last test I asked the GP if it made any difference and she was adamant it makes not difference at all.
Also since increasing my meds to 100mg in December I've had quite a few symptoms such as stomach issues, bad fatigue, pain in my thyroid on the one side and worst of all pain in my joints in numerous places (shoulders, feet, wrists, knees). I have had a bad flu in december which hit me hard so wondering if that affected things.
Any advice would be much appreciated. Thanks in advance.
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Natureguy
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I think only someone who has no understanding would suggest that time of blood draw in relation to taking a dose of thyroid hormone has no effect at all.
My blog on this very subject has some diagrams/graphs to try to illustrate this.
A change from 12 to 0.9 is a substantial difference.
But there is also the simple time of day change in TSH.
helvella - Scheduling Blood Draws
Factors to consider when choosing time for blood draws. Includes links to several documents/webpages and previous HealthUnlocked posts.
Thank you for your reply.I agree with you and I was very surprised when the GP suggested it makes no difference. It doesn't fill you with confidence knowing this way of thinking is very common in GPs. I only get my TSH checked as it is all they'll do and this is the only result they base my medication on. I will see what it comes back at this time. My appointment is at 08.30 so should be a good time fir an accurate reading.
If you don’t take your meds prior to the blood draw the result will be a false low for T4 and T3. If you do take your meds prior it’ll show how high your t4 and t3 levels are getting. The TSH will be the same in either case as the TSH looks much further over days, whereas t4 and t3 levels in blood are a snap shot of what the levels are at that point in time.
I alternate how I take my meds prior or not so I know how high my t4 and t3 levels get or how low they get. My TSH is usually the same. I want to be symptom free so in order the achieve that I ensure that I never go under or over medicated. Meaning t4 or t3 are always in range and TSH is usually around 1.00 to 2.00 max. Any higher than 2.5 and you’ll start to feel symptoms. Any lower than 0.35 and you’ll also start to feel symptoms. A healthy persons TSH is usually 1.00-2.00.
I’m symptom free and have been for over 5 years since adopting to endure my t4 and t4 levels stay in range.
Hi, Sorry for my late response and thanks for your reply.
So I take it that you generally take your meds before a test? The problem for me is the docs only ever take my TSH on my test. They took the others when I was first diagnosed about 6/7 years ago. I know my antibodies back then were about 2000 but not sure about other readings as I dont have access to them tests results anymore.
Im really struggling at the moment with a kind of aching in my thyroid/throat, general pain in the one side of my neck ear and throat. Also been having digestion issues and feeling very tired. I'm not too clued up on optimal levels for T4 and T3.
Well I guess then if your doctor only does TSH blood tests then it doesn’t matter if you take your meds prior or not. That’s really unhelpful if one is trying to find the right t4 or t3 or both levels that’s right for them. Or if you’ve changed your dose you will want to know how the levels have changed. And there’s the issue of only TSH is checked and it’s over or under the ranges then you really do need to check t4 and t3 which means further delay as you’ll need another blood test for then also. So frustrating these doctors who don’t check things thoroughly in the first instance
If you’re in the uk you can have on line access to all your NHS file which includes blood results. Just ask your doctors receptionists. You need to fill out a simple form. Then down load the NHS app on your mobile.
With those symptoms you describe you could be over or under medicated. Do you know your latest blood results?
Taking your medication prior to a blood draw would be counterproductive, especially when measuring T4 and T3 but also for the TSH reading. As levothyroxine is a storage hormone, you are really interested in how your levels are in general on a particular dose, meaning after your body has processed your T4 (levothyroxine). This is why it is advised to have no levothyroxine 24h before a blood draw and why we test after 6-8 weeks after a dose change, as the levels will then have stabilised.
When you take your meds and have a blood draw 2-3h afterwards, this is when your levothyroxine concentration would be highest in your plasma, so when measuring T4 this would perhaps indicate that you are over medicated, even though you are not. In addition, the temporary higher T4 levels could actually lower your TSH in response and as a result (and especially when the GP is only dosing by TSH) you could have a lower TSH than you normally have once your levothyroxine has been processed. So your GP sees the 'low' TSH and is immediately inclined to lower your dose based on these readings. This will not help you at all.
GPs seem to be blatantly unaware that it can make a difference, but this requires knowledge of half life and peak plasma concentrations of medications, which they conveniently ignore.
If your GP only tests the TSH, could you perhaps take a private blood test, so you at least have an idea where your T4 and T3 levels are? If your TSH is hovering between 1 and 2 but you are symptomatic, this could indicate that despite your GP stating that your hormones are 'in range' (and how can he know that if he does not measure the actual hormones?!), they might be low in range and this is why you might experience symptoms.
Yes exactly what I thought and yes I am going to do a full test through thriva I think. These are the results I could get from bloods. Took meds after test apart from in Jan 24.May 23. Serum ferritin 105ng/L (15-275)
May 23. TSH 3.4 (0.4-4.9)
May 23. Vit D 52.6 (>49.9)
May 23. B12 324 ng/L (187-883)
July 24. TSH 5.5 (0.4-4.9)
July 24. Free T4 13.2 (9-19)
Nov 24. TSH 12 (0.4-4.9)
Nov 24. Free T4 15.3 (9-19)
Dec 24. Ferritin 642 (22-501)
Jan 24. Ferritin 297 (22-501)
Jan 24 TSH 0.92 (0.4-4.9) meds took before test 100mg.
The TSH of 12 in November and your T4 of 15.3 would actually indicate that you are very under medicated. I assume that you had a 25mcg increase, so going from 12 to 0.9 seems quite a jump. Did they not test your T4 or T3? That would have been more interesting to see.
Your Vitamin D needs improving, we aim for levels > 75 nmol/l, better if levels are between 100 and 150nmol/l.
Your ferritin looked high in December, but that is normal when you had an infection, as inflammation can artificially increase your ferritin levels. The levels from January indicate that this has come down again, which is good.
Some people tolerate it better, when they do smaller increases, so instead of taking 25mcg extra each day, they take 25mcg every other day and then test after 6-8 weeks. This is a more gradual intake so prevents the sudden increase.
I would test your levels as they are now (without the intake on the morning of the test though)and including T4 and T3, so you get a better picture. Then you would see if you need to adjust the medication or not.
Yes that sounds like a good idea but it means asking my GP to prescribe 2 different strengths of tablet (sounds simple but honestly my doctors is awful and I don't see the same GP every time). I will definately try and get the T3 and T4 done aswell though.
I just wanted to add that any viral infections can have an impact on your thyroid readings and general wellbeing. Subacute thyroiditis for example can be caused by a viral infection (such as flu) and it can cause problems with your thyroid including altered readings, so if that was the case it may take a while for you to get back to your normal self. Try to rest and support your immune system as best as you can.
Once things are more settled, it might be good to check your thyroid readings (TSH, T4 and T3) and test your nutrients as well (Vitamin D, Vitamin B12, folate and iron), as these will support your thyroid and help you make the most of your medication. Hope you feel better soon.
Yes definately I have been quite ill recently and have just had food poisoning aswell in the past week. Definately going to get them nutrient levels checked.
Hi Natureguy being ill definitely affects thyroid levels and how your meds work. I had covid in November and it knocked my levels off. I felt undermedicated and it took ages to settle. Hope you feel better soon but any upset to the system eg illness, late nights, stress etc doubly affects hypothyroid patients and it's why vitamins and good nutrition and sleep are vitally important.
Sorry I hadn't noticed your comment. Yes I think you're right it really does affect things a lot when you're ill. Thank you for your good wishes and hope you are well too. I have a blood test on Thursday so I'll report back on here what my levels are.
latest TSH of 8 makes more sense than the previous 0.9 did (when you consider that it was 12 in dec and then had a dose increase to 100mcg )... so i think you should put the 0.9 down to being ill and ignore it .Taking levo before /after the test is highly unlikely to be the reason for such a large drop in TSH. most of the days TSH is produced in very early hours of morning ,, so the days TSH level is more or less set up , long before you take /or don't take your levo for that day ~ Time of last dose mainly affects ft4 level , not so much the TSH level .
TSH 8 and fT4 14.3 [9-19] 53% fT3 3.9 [2.4 -6] 42% .... assuming you've been on 100mcg daily for at least 6 weeks ?
these results indicate you need another dose increase.... however depending on how you feel and the fact that we don't really know what went on with the 0.9/ illness ... it might ? make sense to stay on same dose and retest again after another month or so .... just in case TSH is still wandering around/ settling down after 'whatever' happened .
but if you currently have clear hypo symptoms ,, then maybe get dose increase asap, cos TSH 8 is not good at all , suggests significant undermedication, which fits with Dec TSH of 12.
Thanks for the reply. Tbh I've had more symptoms since increasing to the 100 such as thyroid pain/aching, stomach issues, joint pain which doesn't really make sense. I still find it really strange after taking my meds before the 0.9 test it is the lowest tsh I've ever had. I have still got symptoms of hypo though, always cold, dry eyes, hoarseness in voice. I was under the impression that t3/t4 levels are a better indicator of what's going on than the tsh. Just not sure how they all relate.
That illness definitely messed with your thyroid results and it is good that you took your meds after the test.
TSH 8.2 - (above range) clearly shows you are still struggling and hypothyroid
T4 53% through the range
T3 41% through the range
So you are ready for the next increase. Most people feel well when T4 and t3 are around 60-70% through the range. How are you feeling at present?
Vitamin D could be a bit higher, you should aim for at least above 75nmol/l, some sources suggest between 100 and 150nmol/l. Are you supplementing with Vit D3 + K2? If you take a quality magnesium supplement as well, this will help with the absorption of Vitamin D supplements.
My last B12 sample was haemolysed as well 🙄, if you took it with MMH they usually send out a replacement kit for you to try again, so you have a chance to repeat it and get the result 😉.
Thanks for the reply. Yes it appears I probably am undermedicated. I haven't been feeling well at all tbh, lots of symptoms but it's hard to know what is down to the thyroid issue. I have taken Vit D but not regularly and only a small dose, I could probably include more in my daily routine and the magnesium. Any suggestions on where to buy quality supplements? Yeah I was a bit disappointed to not get the B12 checked, it was done through the GP so I won't be able to get that done again anytime soon. I've had a message to say I need to book in to discuss my results so I'll see what they suggest. In general do you know many people on levo thyroxine and does the medication stabilise the symptoms once you find the right dose? Thanks
I am not surprised that you are feeling unwell on these figures, and your GP should increase your medication based on these results. You might need a further increase as well, but all in good time. Make sure that once you have been on an increased dose, you get tested again after 6-8 weeks, so you can follow your progress and increase further, if necessary.
The majority of people get on well with levothyroxine, IF they are on the correct replacement dose (around 1.6 mcg per kg of body weight) and if the GPs don't dose by TSH only. However, there are some people that do not convert T4 to T3 very well, and they might need T3 as well to feel okay. However, you should try if you can achieve good levels of T4 and T3 on levothyroxine only first, as this is the easiest option.
Supplements do play a big part as well in how well the medication can be utilised by the body, as optimal levels of nutrients can influence the conversion from T4 to T3. With regards to the D3, most people take 3000IU +K2 daily to achieve optimal levels, some might need more. I take Nutravita D3 +K2 3000IU available on Amazon (orange and yellow label) and could achieve levels above 100nmol/l. But you should test your levels again after 3 months to see your progress and to see if you need to adjust. However, you need to be consistent, so maybe have a daily reminder on your phone or have a little pillbox, so you can see, if you have taken them.
Good magnesium supplements are also available on Amazon, bioavailable formulations of magnesium are citrate (can be laxative in higher doses), malate, glycinate and taurate. Avoid 'buffered' preparations, as they contain magnesium oxide, which cannot easily be absorbed.
It is a bit of a bumpy road at the beginning, but don't worry, it will get better! 🤗
Thank you. I'll see how I go and what the doc suggests. I'm going to get on top of the supplements aswell and see if that makes a difference. Hopefully the next set of blood results will be better. I'm still going to request the b12 etc.. again as it would be interesting to have these. I'll report back with any info.
If your GP does not test your B12 for a while, you could try to do a private test? Monitor my Health do an anaemia test (testing Haemoglobin, ferritin, transferritin saturation, active B12 and folate); if you use the code THYROIDUK10, you will get a 10% discount on the test. Might be worth considering it, as good levels of ferritin, folate as well as B12 are needed for supporting the work of your thyroid hormones.
I will definitely have a look at monitor my health, see if it's worth me doing and depending on the gp's attitude to things. Will report back in the coming weeks. Thank you 😊
Hi Natureguy . Those latest results suggest you're still not very well. The bad dose of flu will have had an effect on the efficiency of your levothyroxine. You've had some good advice here and I would say maybe let things settle down whilst you recover fully from the bad flu before considering a dose change . When hypothyroid we don't bounce back from anything! Focus on good food and decent sleep and supplement if necessary. I use the Vit D with K2 spray from Boots which is often on offer and not expensive. If your B vitamins come back low after retest then others on here will have some suggestions for decent supplements. Your thyroid levels may settle but are a bit low at the moment. Definitely the TSH is obviously too high but the T4 should be higher up the range. Your overall health has been impacted by the flu so you won't feel better for a while. Unfortunately everything to do with thyroid takes a while. When you don't feel well though it feels forever! I do know how you feel.
Hi. Yes I had thought myself about just keeping the dose the same for a bit longer until I recover a bit. Also I'd like to give my supplements time to kick in. Yes I had flu really bad in December then a cold again on Jan and a few weeks ago I was ill again with suspected food poisoning or possibly norovirus. So my body has really been bombarded. Adding in the fact I have daily ongoing stress it's no wonder I'm not feeling great, I really need to sort my life out lol. Thank you for the suggestions and sympathy lol, I know lots of people on here have gone through tough times with their health which is why I trust advice on here more than my GP. Thank you 😊
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