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Thyroid UK
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The benefits of taking T3 with T4

Seeing GP Monday and need the correct, concise information of the possible benefits of taking T3 with T4. Have had hypothyroidism & Hashis for a long time and have taken thyroxine for some years although not as long as since I was diagnosed in the beginning as it wasnt thought necessary! Strangely since I retired two years ago the hypothyroidism has really kicked in and I struggle with feeling well particularly the exhaustion and weight gain. I really would like to be enjoying my retirement more and this morning I've only just been able to haul myself out of bed at 10 a.m. and I went to bed at 9! I am going to my GP Monday for the results of an echocardiogram because I have also been having palpitations and missed heartbeats and would really like to ask her if I could try taking T3 along with T4 just to see if it improves my condition. But I want to go armed with a concise piece of information on the subject, so any suggestions as to what I could copy for her please? (a friend has improved dramatically with added T3 and before had all the symptoms that I now have and I've read stories on here about the improvement). What is the general concensus of how NHS GPs feel about giving out T3? Any help or advice here please, would be greatly appreciated.

Desperate to feel well again! Sheila

19 Replies

If you email louise.warvill@thyroiduk.org and ask for a copy of the Pulse Online article by Dr Toft who was President of the British Thyroid Association and in question 6 you will read that it is o.k. for us to have a low or suppressed TSH or the addition of T3 to a reduced T4.

Some GP's believe it is the correct thing to do by keeping us within the reference range.



You could start with the article " Why T4 does Not Work" and find more links using the search.

Of course, your doctor may not be impressed with any of it. They have to be instructed by whatever the NHS dictates so I hope he is amenable.


I was taken off of T3 for exactly that reason, missing, irratic heat beats. I have since found out that it wasn't so much my thyroid medication that was the trouble (although it was this that was causing the heart problems) as the lack of iron, which is very important for the conversion of T4 to T3 and the uptake of T3 into your cells (which is where it really needs to go). Since increasing my ferritin levels (iron storage) from a very low 12 to over 40 (it really needs to be over 70 and nearer 90 for your body to be able to use your T4 properly) I have had to REDUCE my thyroxine twice as my body is now using my medication a lot better.

What I'm trying to say is that I didn't actually need T3 at all but my GP was refusing to test the relevant vitamins, such as B12, VitD, iron, ferritin and folates, that are key for thyroid medication to work properly. Since I obtained an endo and he did all the relevent test and has, one by one, corrected all the vital vitamins my thyroid medication needs I am a different person. I had low B12, low VitD, low iron and low ferritin so my medication did not have a chance really. Like you I thought T3 was my answer, which only caused me heart issues, but if my GP would have sorted my vitamins first I would have known how well T4 can work and would have had no need to even try T3.

Just thought it might be useful for you to have a different slant on the situation.

Moggie x


Interesting Moggie. I am on a trial of 10mcg T3 together with 100 mcg T4, my previous medication being 125mcg T4 only, but sadly I have been noticing symptoms of angina when walking on inclines recently. Looking at the leaflet that came with the T3 it says not to take if one has angina. I am not sure if I already had an unrecognised underlying heart problem but my instincts are to stop taking the T3 as it is not agreeing with me. I will consult my Doctor over this next week. I had hoped the T3 would help alleviate my muscle and joint pains (fibromyalgia) but cannot honestly say it has made any difference. It could be the T3 dose is too low, but as my heart is reacting I will never know.

I was so enthusiastic to take the T3 after so many good reports, but just goes to show, especially when you are older (I am 72) to proceed with caution, which is what I think sydneymark should do.


As I have already said, iron was the key one for me. Yes I felt better once my vitd and B12 were at optimum levels but the difference iron has made to my thyroid medication and my feeling of well being is amazing, which is what has made me realise that I didn't need T3 at all (hence the heart problems). If only my GP had done the right thing in the first place it would have saved me a lot of time and effort and the NHS an awful lot of money in heart scans, untold trips to the GP and countless other hosp appts. The sad thing is that the clues where there in my blood results all along, and I had repeatedly questioned my GP over my iron levels (she even drew me little pictures to help me understand how I did not have an iron problem!!!!) but she decided that she knew best, thank god my endo stepped in and took over my care.

I do have a link on my works computer regarding iron levels and thyroid medication which has been very useful to more than one pereson on here, if you want I will link it on this question on Monday.

Moggie x


Thanks Moggie, I would be grateful to see this link. Is being tested for iron deficiency a standard test that a GP wouldnt mind requesting please.


Hi Moggie,

I wondered if you would be so kind to send me information regarding iron levels and Thyroid medication.

I have slightly low on iron and have Hashimotos disease.

many thanks



Hi please can I ask do you take the t3 and t4 together first thing in the morning. D x


Thanks everybody, this is such a complicated subject isnt it? and our bodies are all so different and how we react differently to drugs. I might now bring up the subject of vitamins with my GP. I only know last time I wasnt deficient in B12 but may ask about the other ones.


Just found it.


and a normal ferritin blood test will tell you and your GP what you want to know. I have asked two GP's and two endo's so far about the link between thyroid medication and iron levels and not one of them knew anything about it - shameful when you think about it as they re supposed to be the experts. Its only from this site and research that you start to see the whole picture and you can then piece your particular jigsaw together and I do agree with Joyia that T3 needs careful handling and a cautious approach.

Good luck with the GP on Monday

Moggie x

1 like

Thank you Moggie, you help many of us.


Moggie, thanks so much for your information. I suffer with low ferritin and think that it has some relevance to my own troubles with taking T4 and T3 - could you tell me what you took to start to increase your levels please? Thanks you :)


So sorry it has taken so long to get back to you but I did not see your response. If you use the "reply to this" button under someone's name they get an email to say you want to communicate or answer them.

Anyway, back to your question, can I ask how low your ferritin is please and did you get it tested by the GP.

Moggie x


Sorry Moggie, I'm not brilliant at using this site! Thanks for replying.

At my last test my serum ferritin was 50ng/ML (and I believe the range is 50-70 minimum but 70-90 optimal?). Just to confuse things though, while my serum folate was also low (8.6 with a range of 2.1-20), my percentage iron saturation was high (54% with a range of 12-45%)!? Serum TIBC was low at 46 (range of 45-66) and serum iron level was relatively high (25 with a range of 9-30), so I was left very confused as to whether I needed to supplement with anything!

My GP, of course, felt that as everything was officially 'in range', nothing was needed, so I'm on my own with this.

I have a good (enough) Endo who I've persuaded to see things my way a little (thanks a lot to this site) and take 200mcg T4 plus 40mcg T3 everyday - and while I'd say I'm not working brilliantly, I am at least functioning to a degree and able to work two days a week now, which is a lot better than it was before!

I know there's a link between low ferritin and thyroid though and so clicked on this chain to read further.

Any thoughts about my iron/ferritin etc, would be gratefully received :o)

Thanks, Helen x


Hi Helen,

I have just compared my results to yours and at a glance I would say that your iron is o.k.

My saturated transferritin was 12 with a 15 - 50 range and serum iron was 9.8 with a range of 14 - 28 so as you can see both of these are low - hence I was given iron supplements.

Your results are a bit puzzling and if I were you I would ask a question - something along the lines of "can anyone help me with my iron results" as a heading and then list all the results to see what other people make of it. The puzzling one for me is your iron saturation - have you been taking iron supplements at all.

Also have you had your B12 and vitd checked as both of these, if low, can cause thyroid like symptoms. Sorry I wasn't much help and please do post a question as I would be interested in the answers as well.

Thats an awful lot of thyroid medication to be taking and still feeling unwell, get your b12 and vitd checked first and if these come back o.k. (not NHS o.k. but thyroid o.k. - there is a big difference) then I would be looking into gut issues if I were you - something along the lines of gluten intolerance or coeliac.

Moggie x


Thanks for this. I agree they're a bit puzzling - I've looked on the internet to try and understand what they mean (if anything) but with no luck so far, your idea of a question is a good one :o)

Yes, I've had B12 and Vit D both checked - both were low (not particularly NHS low but thyroid low) so I take B12 sublingually (the Metho......can't remember what it's called, version, as recommended by this site) and I am already on Calcium with Vit D3 from the Drs for rapidly thinning bones. As to gut, yes, definitely a problem for me and I'm totally gluten free now (on recommendation of my Endo actually, but after reaching the conclusion it was needed myself too). That's helped a lot.

I have Hashimotos and also test positive for an autoimmune liver issue, though again the GP seems to think this isn't worth investigating further at the moment. I know from doing Genova Saliva tests that my Adrenals are a major problem and so I have experimented in recent months with reducing my T4 and increasing T3 to see if this helps, but it really didn't suit me and so many horrible hypo symptoms returned when I cut the T4 to 50mcg per day that I gave up. I know I don't have a RT3 issue, as I've had this checked too, and I definitely feel better when I'm on a healthy dose of T4, yet also need the T3 for specific symptos - in that they only disappear when I have T3 too that is! The Endo has concluded CFS, on top of the Hashimotos, but I'm not happy to accept that diagnosis and feel there's more to be understood - I'm sure you know how it is.

Thanks again for your help,

Helen x


Well you have just about covered all angles haven't you but what a shame you are still feeling ill.

Have you tried symprove - my friend said it has made such a difference to her, its not cheap but if you are a member of thyroiduk you can get a discount from the nutricentre of if not google it and find the cheapest. Its had rave reviews from a university hosp and been in the papers, so well tried and tested.

Good luck with finding you answers and I wish you well.

Moggie x


The degree of variability that arises is pretty amazing.

I had many years (15+) of serious hypothyroidism and many associated illnesses, but have never experienced even the slightest problem with taking T3. Even when e.g i accidentally manage to take my 2 x20mcg doses far too close toegther or stuff like that.

The nearest to a heart issue I've experienced (and it wasn't really) is that my pulse tended to start to rise if i was getting to be a bit over replaced, and even that seems to have faded with work on reducing my too high cortisol. i.e. no idea what the mechanism might be, but there do seem to be 'supporting' factors that make a difefrence int his regard...



I feel you. I just stopped taking my t4 .

I took half dose of t3. I felt beter now im feeling a bit hypo.

I am going to doc tomoro after 4 months ago.

I feel im allergic to t4. Im also just started menapause.

I am on adrenal support.

I hope the t3 works for u you deserve your life to feel normal.


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