Thyroid UK
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TSH needs to be lower, but FT4 already high

Hi all

I'm a 'newbie' on here (popped over from PA forum) and would appreciate your thoughts, please.

My GP reduced my Levithyroxine, just slightly, last November (2016) because Free T4 was 31 pmol/L (9-23). FT4 had previously been running at around 23 pmol/L (12-22) for the past few years. I have to say, I wasn't feeling any effects of having a 'raised' FT4 so GP clearly only treating numbers!

So now, 4 months later, I am feeling so exhausted, much more so that in October, before the reduction of Levithyroxine. I have an appt with another GP this afternoon (5 April) to ask for TSH, FT4 and FT3 to be done and, hopefully, to increase Levithyroxine back to previous level, ie back to 150/125 mcg alt days from 125 mcg daily - yes, a pathetic drop but my tiredness has really taken a dive.

I'm also in the process of trying to convince my GP that I have Vit B12 deficiency - (he, at least, agreed to test Homocysteine and MMA levels, so just waiting for the MMA to come back, with other markers suggesing B12 def)

My question is, as my B12 is at/below bottom of range, plus other markers suggestive of deficiency, would it be sensible to ask the GP this afternoon (a different one) if she might consider a trial on B12 injections, as these might be effective much more quickly ;) I see my 'regular' GP in two weeks time (he's on holiday just now) I don't like asking another GP to do something that my regular GP is not happy with, especially as he is Senior Partner and today's GP is 'registrar', so not permanent at surgery (as far as I know)

Just a bit of a dilemma. Thanks for your thoughts :)

17 Replies

are you sure that whenever blood is drawn for thyroid tests that

appointment is early orning

fasting and only water to drink

you never never take levothyroxine in previous 24hours


Hi reallyfedup123

Thanks for your reply. More recently, I've had bloods taken later in the day (when phlebotomist is at surgery, so easier than parking at hospital) so that is afternoon. In the past, when I've had blood taken in the morning, it hasn't seemed to make much difference.

However, I don't ever remember getting blood taken before having any breakfast so, I had already decided to get any blood samples taken for thyroid early in the morning and before anything other than water, also before taking morning dose of thyroxine.

Thanks for the reminder ;)

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You could ask for a trial of B12 injections - but from reading here and on the PAS Forum it seems almost impossible for GP's to prescribe this inexpensive and effective treatment. They would rather give you anti-depresssants - expensive nerve conduction tests and so on ....

Let's hope they test your FT3 this time - and anti-bodies which may give you a better understanding of what is going on. Also Ferritin - Folate and VitD need to be tested and need to be optimal - all these along with B12 - are involved in the processing of thyroid hormones in the body. In particular the conversion of T4 into T3. If they are all low in range then that may explain the high T4 which cannot convert into T3. Hence the importance of the T3 test.

Nothing scientific you understand - just my own ponderings :-)


You don't say what your TSH is, but if it's high, and your FT4 is high, that suggests that you are not efficiently converting that T4 into T3. And, the answer to that is not to keep the FT4 way over the top of range, but to lower the T4, and add in some T3 - difficult as things stand, I know. But, keep increasing the dose of T4 will bring it's own problems.

So, why are you converting? Do you have Hashi's? Have you had your antibodies tested? Have you had your vit D, folate and ferritin tested? These all need to be optimal for you to convert properly, not just in range. We already know that you have low B12, so the others could be sub-optimal, too.

I'm afraid I cannot help you with your B12 dilemma. :(

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Thank you, you've mentioned conversion and I think that may be an issue.

My TSH tends to be around 0.5 ish, whereas I'm better when it's below 0.2. It does tend to fluctuate (maybe because I get blood tests in afternoons, rather than before taking thyroxine and breakfast etc) The last TSH is actually quite low, at 0.03 (0.2-4.2) but the FT4 has previously been only just out of range, around 24 (12-22) and that's been accepted by the docs.

The latest, at 31pmol/L (12-22), is the highest it's been but, yes, I appreciate your comment that FT4 getting too high can be problematic.

In UK, I don't think GPs will treat with T3, unfortunately but, if I can get treatment for B12, maybe conversion would improve?

I'm expecting the doc to agree to blood tests when I see her this pm and I'll make sure I get the blood test before taking thyroxine, before anything to eat/drink. Also, I'm hoping she will agree to test FT3 and FT4 so that the results are available when I have appt to see regular GP re B12 (he doesn't agree I'm deficient, in spite of other blood tests and symptoms etc :(



Oh dear. I wish you'd given your TSH level in your original post, because that changes everything. When you said 'TSH needs to be lower...' I was thinking it was about four or something. So, forget what I said, It is so important that you give all the details right from the start.

However, you may still have a conversion problem, so you do need to get your FT4 and FT3 tested. It is very hard to get T3 prescribed in the UK, but you could always buy your own.

It is so important to have your test early in the morning before food or levo. That way you will get your TSH at its highest. If you take your levo on the morning of the test, you are going to get a false high. So, all things considered, we really don't know what we're dealing with at all! lol

So, what exactly is your B12 level?


Hi Marz

Thanks for your response and 'ponderings' :)

Yes, I'm already 'on a mission' re B12 deficiency with my regular GP, managed to get Homocysteine and MMA checked, the latter result is still to arrive.

Folate is high/out of range,

B12 low - just out of range/just in range,

Vit D is mid-range but I've recently increased Vti D suppliment to make sure that's OK (have been deficient but had high dose suppliment, now maintaining levels myself)

I've not had Ferritin levels checked since 2013 but was ok then. Not sure of the value of insisting test and irritating GP at the moment. Don't want to push it too far just yet. ;)

It's more the affect of low/deficient B12 on how T3 and T4 which is what I need to be learning just now. I know there's a relationship between them but not much more.

Yes, I'll be asking for TSH, FT3 and FT4 to be done when I see this doc later today so that the results will be available when I see my GP in a couple of weeks, by which time, hopefully, MMA result will also be available.

No way will they be prescribing antidepressants - I'm already on decent dose which is working well. They wouldn't dare change that prescription - over my dead body!!! (Nothing else has been effective and I'm on current ones for the duration ... ) ;)

I think it would be worthwhile offering me a trial of Vit B12, especially considering all the symptoms I have that are not improved with thyroxine being optimum (as in the past) Like you say, though, the medical staff don't seem to be very clued up on Vits at all. It took me years before I got Thyroxine!!!

Anyway, many thanks for your ponderings. Much appreciated



Here is our last discussion on the PAS forum in the above link :-) - with the Link for Private Testing if you do not get the FT3 tested through your GP.

Am posting the above link - just in case you have not seen it. Scroll down for the neurological and other symptoms of B12D. With Low B12 and Low Thyroid - even low VitD - it is possible when all are optimal you will not be needing the AD's - or can reduce the dose. Some AD's can skew thyroid test results and are not compatible with Levo.



Great, yes, I hadn't thought of getting private tests, if doc won't agree. Thanks for reminding me and for the links.

As for the ADs, I've been on and off ADs since I was a teenager and the current ones (that actually work) for the last 20yrs so, yes, would be great if I could stop/reduce them but I won't hold my breath just yet ;)

Have you any links to hand re ADs skewing thyroid? Also, will need to check out incompatibilities although I really don't want to find any ;)

Thanks very much - great stuff :)


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It should tell you which drugs to avoid on the PIL inside the packet of your AD's .... or you can check it out with Dr Google :-) You haven't mentioned the name of the Ad so I am not able to do it for you :-)

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JMN2017 - one of many research papers .... so much to plough through ...

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Thanks Marz

I've had a quick look at the article you've linked but I'm not concentrating well at the moment so will need to look at it when brain is in a lower gear.

The ABs I'm taking are very old-fashioned MAOIs, so a lot of interactions re food etc. I'll check out the very long list I have and see if there is anything that would set alarm bells ringing.

Again, many thanks.


PS Just about to start new thread re visit to doc!


Iron is extremely important for conversion, too. It's not just B12 involved. You need good levels of folate, vit D3, zinc, selenium too.

If you're taking vit D3, are you also taking vit K2-MK7? That is important because D3 increases absorption of calcium from food, and K2 directs it into the bones and teeth, rather than the soft tissues.


Try they are a charity set up by Dr Chandy

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Apologies. I thought I had included levels but clearly not. So sorry.

I accept your revised thoughts.

Here are sme of the results you were asking about

Feb 2016

Vit D - 69.81 nmol/L [50 - 140]

Oct 2016

Folate <20 ng/ml (4.6 - 18.7)

B12 - 165 ng/L (197-771)

March 2017

B12 - 215 ng/L [197 - 771]

Folate - 18.7 ng/ml (<3 ug/L suggestive of folate deficiency)

Zinc - 12.6 umol/L [11 - 18]

Magnesium - 0.75 mmol/l [0.7 - 1]

Homocysteine - 14.6 umol/L [0.0 - 16.0]

MMA - awaiting result

Hb - 13 g/dL [11.5 - 16.5]

No, I haven't ever taken Vit K2 MK7, so that is something else I need to sort out.

"K2 directs it into the bones and teeth, rather than the soft tissues"

Would this happen to be a cause of stiffness and pain when moving (like I've dug up a football pitch y'day)? Just an interesting thought ...?

Again, many thanks for your thoughts


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greygoose and other members

May I ask, what amount of K2 MK2 should I be looking for and any suggestions re brands, or what to avoid etc?

Many thanks



("K2 directs it into the bones and teeth, rather than the soft tissues"

Would this happen to be a cause of stiffness and pain when moving (like I've dug up a football pitch y'day)? Just an interesting thought ...?)

Probably not, but excess calcium that's not directed into the bones will put you at risk of kidney stones and heart attacks. You want about 100 mcg vit K2 MK7. And that's about all that can be said about it.

Zinc is a bit low. No point in testing magnesium, because it will always be in range, due to the way the body handles magnesium. But, that doesn't mean you're not deficient. I would take some, if I were you, it's a co-factor of vit D3. :)

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