What are the levels of T3 and T4 to aim for? Or is it very individual?

Where in the reference ranges for T3 and T4 should we be aiming to be? For instance, if my local reference range for T3 is 3.1-6.8, should I aim to be around 4, or more towards 6.8?

Or does it vary from individual to individual? And would that mean we should persuade doc to let us keep increasing (and checking) dose until we feel the best we can be?

52 Replies

  • Yes, the best way to know if the medication is working is 'how you feel'. The blood tests should only be used as guidelines. If you feel well you are on the right dose.

  • The last question is the important one. It really should be how we feel. If that means a TSH of 2.9 , and a T3 of 3.1, fine. But if you still feel bad at that level, then by all means keep raising meds until you feel fine.

    It could mean a TSH of well below 1 and a T3 right at the top of the range, but so long as it is no higher and you feel better, that is what counts.

    Dr Toft says that in his book, 'Understanding Thyroid Disorders'.

    Marie XX

  • Just don't continue on any of the drugs most doc give, take ARMOUR OR IF you only need T3 then take it.

  • While many people do find that Levo does not work for them, it is always worth giving it a chance first, for two reasons:

    First, it may well work fine. There are people on here who take Levo and are perfectly happy with it.

    Second, going it alone and just ignoring the doctor is a big step, and can be expensive.

    Until one is sure that Levo is not working, and has blood tests to prove it, then this is not the next step. There are other factors to consider such as iron/ferritin/folate, B12, D3.

    I am one of those for whom Levo did not work, and I fully accept that is a possibility in this case, but caution is important too. Not everybody can ignore the doctor and self-medicate.

    Better where possible to try to get the doctor on our side - difficult, I know, but some have managed it.

    Marie xx

  • I have just started NDT and am going to have a repeat blood test done privately when I feel better, to compare the levels. Not because I want to alter my dose on tests, more because I am just curious and would quite like a benchmark for future reference. My ft3&4 were both low in range, and apparently people feel best usually in the top quarter of the range.

  • This will give you an idea of optimal thyroid test levels but other tests also have an impact on your wellness while you are medicating with hormone.


  • Are there others you would suggest I keep track of, once I am well?

  • Harry, this can be rather individual and if you notice on the list which I inadvertently forgot to post (now corrected), you will also see it can differ between men and women. It's much more complicated than the NHS makes it appear. If you have secondary hypothyroidism, you need to find out what it is. If you are low in iodine or have a direct autoimmune attack against your thyroid gland itself, it is easier to treat I think, but if your thyroid is producing enough hormone and the attack is against other areas which keep it from reaching receptors, it can take more calculating. If you have cortisol problems, those would have to be corrected as well. I wish I could understand it better myself.

    Check out those lab tests in the link and see if you identify with any of them.

    I like this man's observations about this complicated issue of Hashimoto as an autoimmune condition:

  • My feeling so far is that I have 'fairly simple' autoimmune thyroiditis. I haven't been ill as long as a lot of people and everything points to thyroid symptoms rather than adrenals, although I have taken adrenal support too just to make sure. Yes I like these videos too. Thanks x

  • Harry, maybe you will be one of the lucky ones. If your "attack" has stopped or controlled if I can use that term, it would appear you may feel very well in time. Stress and leaky gut are two areas you might work on as you get well. Refined food and antibiotics are main contributors as far as intake is concerned but people do not understand that stress as in chronic muscle tension, especially the gut, reduces blood supply and, of course, it's well known this has a lot to do with your immunity. You could look into biofeedback.

    I wish you every success.

  • Thanks. I've been working on stress for quite a while in therapy etc. Although currently my sister is increasing my levels considerably! But that's life :-/

  • I've got low TSH and take Serotonin in form of anti-depressants and still feel really exhausted most of time.

  • This is the sneaky part of autoimmune Hashimoto.

    In addition, D1 activity is also lower in females (143,144), making women more prone to tissue hypothyroidism, with resultant depression, fatigue, fibromyalgia, chronic fatigue syndrome, and obesity despite having normal TSH levels.

    I think many of us suffer from "lack of cellular transporters":

    This high incidence of reduced cellular thyroid transport seen with these conditions makes standard thyroid tests a poor indicator of cellular thyroid levels in the presence of such conditions. The pituitary has different transporters than every other tissue in the body; the thyroid transporters in the body are very energy dependent and affected by numerous conditions while the pituitary is minimally affected. Because the pituitary remains unaffected, there is no elevation in TSH despite wide-spread tissue hypothyroidism, making the TSH an inaccurate marker for tissue T3 levels under the numerous conditions listed above (1,3,4,17,22,43,50,52,55,59,60,61).

    There are some links for dieodinase. nahypothyroidism.org/thyroi...

  • Hi - many thanks for your reply, Heloise. I am new to this. I have fibromyalgia, have had anxiety all my life though fatigue is greater thing now. I also used to be a skinny thing. Now I am overweight though this could also be a because of the antidepressants, well-known for increased weight and also my age. Probably a little of each. Also my Thyroid peoxidase antobodies (which I asked for) came back negative but I thought that would show positive for Hashimotos? I wanted to rule this out after reading an article. Forgive me, I'm knew to all this and the learning curve is steep!

  • Kirby, totally understand your confusion. I knew so little back in the day and discovered the medical profession seemed to put all the eggs in one basket....dose with synthetic T4. (Unfortunately they abandoned natural desiccated thyroid extract from porcine which is much closer to our own (T4, T3, T2, T1).

    When you assumed your TPO would be positive....well, now we know there are so many other areas of autoimmune attacks all considered Hashimoto. The other videos from Dr. Clark explain the other 21 areas which would produce low thyroid symptoms. I've written notes on all of them and if you have any idea of where your weakness may appear, I could tell you which ones to watch. You may need other supplements, etc. to support your thyroid hormone.

    Did you start with Graves? #9


    Antibodies are discussed in #8

    If you are menopausal, #11 may be pertinent. I think they list all of his videos on the YouTube site. I'll post #20 because this has to do inflammatory cytokenes which close T3 receptors which causes weight gain.

    Hope this will help.

  • Thanks Heloise - just watched that video. No, not been diagnosed with Graves. Always had anxiety - then gradually fatigue set in in my 40s and 50s, sleep problems, diagnosed with fibro at 50, now premenopausal, always had very heavy and painful periods, weak bladder, feel cold a lot now (all these also consistent with fibro). I'm now worried that as well as low TSH, I have low lymphocyte. Not been told about that one before.

  • Did you notice what he said about cytokines? If inflammation is the basic problem, Barry Sears is an expert on this.

    Personally I don't believe in the fibro diagnosis, if anything and we sound similar , weak adrenals also account for all those symptoms. This impacts your thyroid greatly. How about some adrenal support. I know one dr in the uk always uses both to treat thyroid.

  • I couldn't hear very it very well for some reason even though turned up full but yes I do have some inflammation I think. Mmmm, I've noticed quite a bit of antagonism on these boards re fibro and don't understand it. While there may be people with undiagnosed thyroid problems I don't believe they're mutually exclusive. When I had my fibro diagnosis everything else that I'd had in the previous 50 years made sense to me. We have a bad enough time of it as it is with UNUM and the DWP taking a dim view of fibro and ME. We should surely all be supporting one another. Many conditions have overlaps. What about MS too?

  • It's not the condition, it's the name that is unbelieved. It's just felt that low thyroid has caused the fibro symptoms but their refusal to treat it as a thyroid problem leaves the patient without the benefit they may receive. They both seem to use antidepressants for the pain.

    Even MS can be a false diagnosis. A doctor who practiced medicine for 35 years stated that many people said to have MS actually did not. They observed that after autopsy.

    Have you tried GABA? which calms neurotransmitters.

  • There are many people who've had their thyroids checked thoroughly - I'm just speaking to some now in another group and they still have fibromyalgia. Incidentally, my brother has PPMS - the myelin depletion and other lesions are completely consistent with MS. I accept that not everybody gets a correct diagnosis first time but that doesn't mean you dismiss everyone with MS, Fibro and ME. There are many conditions that present in similar ways.

  • Oh, absolutely, but as I said, it's not the condition that is being dismissed, goodness, no. I'm sure these diagnoses are very difficult. Has your brother considered LDN (low dose naltrexone? I think they have done newer research regarding MS. You might check that out.

  • Yes, he's tried many many things. The problem is that lots of the research and treatments are for relapse-remit MS which has a different aetiology than PPMS and therefore many of the treatments aren't applicable.

  • I wasn't aware of the difference and found this info.

    Is there any treatment for primary progressive multiple sclerosis?

    At this time, there is no FDA-approved treatment for PPMS. Research studies usually focus on medications for the relapsing forms of MS. There have only been a handful of treatment studies specifically for PPMS; the results so far have not shown a significant treatment effect. The standard FDA-approved medications for MS (interferons, glatiramer acetate, mitoxantrone, natalizumab) have not been proven useful in slowing the progression of PPMS.

    "I don't see LDN mentioned but it is a very old and inexpensive drug formerly used for alcoholics in much higher doses. They decided to test it for MS because of its affect on autoimmunity.

    It must be dreadful to live with."

  • Yes, a lot of people don't realize about the different forms of MS and it is very frustrating for my brother when so many treatments are for relapse-remit rather than PPMS. there's also a secondary progressive MS which begins as RR form then progresses. My brother has tried lots of things and takes many supplements but his mobility has deteriorated gradually over the years. It is dreadful but he's not one to bemoan his fate! He has tried LDN but I think (though I'm not certain) that he had to stop it because it gave him spasms. Either that or it disturbed his sleep. He now takes other meds as well as his supplements

  • You have all my symptoms. LOTS OF PAIN. Have you tested your adrenals with the saliva test? They must be on there way to being healthy beforer treating thyroid, as well as good mag. levels and iron levels.

  • Try to wean off antidepressants sicne they can cause hypothyroidism... and you can't get well if you are on them.. I walk daily in the sun, and also research has now proved that exercise is just as good as drugs for depression. No kidding, it helps me so much.

  • We are all different, Pooder. I've never really suffered from depression that much but anxiety all my life. That is one of the worst things I have suffered. That is why i was prescribed anti-depressants. If I tell you that the fatigue and the weight gain have absolutely nothing on the anxiety you will understand and wouldn't even mention the futility of anti-depressants. they have helped me 100 per cent, even with the side-effects. I do find it slightly patronising to tell me 'to go for a walk int he sun'.

  • I've used them to great effect for anxiety and depression and as long as they're prescribed correctly, they can be lifesavers. You have to do what you have to do. :-)

  • Agreed PB! :-)

  • Antidepressants can cause hypothyroidism.

  • According to that video that Heloise posted they are supposed to help it. They certainly helped my anxiety. I accept that the anti-depressants could be responsible for my weight gain. You have to way up the pros and the cons.

  • pooderdog, what antidepressants cause hypothyroidism?

  • Also just know that pain killers, since we usually have pain, you must be off of these for your adrenals to heal... I just found that out.

  • In my opinion it is very different from one individual to another. I need low TSH (0.1-0.3) to feel well while other feel ill at that level. Since my doctor agreed to treat me by my symptoms and not by the blood tests, we have made great progress. A lot of time (3 years) was wasted chasing on blood test results.

  • T3, do you have any tips for being assertive or whatever it took to achieve that? So many in the UK continue to suffer and find it impossible to go outside the boundaries or cannot afford to. And also cannot afford to wait 3 years before their health to hit bottom.

  • Just learning how to navigate the nhs with thyroid problems is a long and exhausting road. You have to be prepared to alter your tactics at a moment's notice depending on what you're faced with. I think it depends on how your gp is. Some refuse to do anything for you, in which case you have to move on and find another. Some will only treat based on their interpretation of your bloods, in which case Dr Toft's book (which says that some people feel better with a tsh under 1, and also that symptoms should be alleviated) and lots of letter writing (and insisting on the letters going in your file) might help.

    Having said all this, the only way I got effective treatment was via a private doc, which is not really what you're talking about. That briefly lit a fire under my nhs endo, who then agreed to recommend t3 treatment, but my gp balked. And then the endo dumped me, which was not necessarily bad news for me but it might have been had I no other options.

    Self-treatment is the only option for many people. Or at least it may be the only alternative to feeling awful.

  • Well, I've been called a non compliant patient and it is not pleasant so a certain degree of "spine" is involved. In the states, I don't think they can abandon a patient totally. I suppose the only effective action would be to change the standard of treatment.

  • You absolutely need 'spine'! :-) But I think some of us got it by hitting rock bottom. :-)

    Without wishing to sound melodramatic, I have had a certain amount of trauma from dealing with the nhs, to the degree that my heart pounds and I get a dry mouth when I have to ring them for any reason, and I shake when I go to the surgery. I don't seem to have a less horrible time when I'm nice, compliant, etc, so my attitude and manners don't seem to affect the interaction, and I keep that in mind.

    Also, I refuse to be treated badly (ie I don't put up with anything from them I wouldn't take from anyone else), so bad treatment means finding a different doc.

    I find most interaction with the nhs means being treated with at least some lack of courtesy, so I'm prepared for that, but I won't be spoken rudely to or similar. I make complaints too.

    Have you been treated in the States? I don't know what the protocol is, but my mum lives in the US and the orthopedist who treated her when she broke her arm has refused to treat her current injury. No one can/will tell her why, so she found herself with a broken wrist (she slipped on ice), unable to drive and having to find another doc pronto.

  • With a stress condition, you would think the last person to add stress would be your GP. They do have the power to make life difficult unfortunately. I always feel worse if I don't defend myself and hate to see others not doing so.

    I'm surprised at your mother's treatment. It may be that the doctor no longer accepted whatever insurance she had. It does sound unusual though.

  • We still have no idea what happened there! It was a pain in the bum, and she felt - rightly or wrongly - a bit hurt because they'd had a good relationship and she wanted him to help her when she needed help. You're so freaking vulnerable when it comes to doctors. You go to them when you need help, you're asking for help, so you're just so defenceless and they have all the power.

    I don't think her insurance has changed, but maybe he just had his hands full. We'll never know.

    Yes, it would be nice if they attempted to reduce the already stressful nature of the situation. But I'm glad to hear you're defending yourself! I have an old-fashioned friend who just takes what they give out and it drives me nuts. :-)

  • Well, you take care and try to stay sane. I hear the next life is going to be great!

  • Lol. Fingers crossed! :-)

  • The key to being assertive is gaining good sound knowledge. I used Paul Robinson's book 'Recovering with T3' to gain a good background knowledge. I used this site and 'Stop the Thyroid Madness' and then some general searching to grow my knowledge and confidence to ask to go T3 only. Bear in mind I had taken quite some time discovering/proving that T4 only was not working for me. Having someone else to talk to and reason it out with is also helpful. My wife was brilliant and often came with me to describe how bad I was or make sure I said everything I needed to (important when your brain is foggy) and it helped my confidence a lot. There is some good advice above from Marram (Marie) who is an admin and has good experience. Hope this helps.

  • That's what makes this forum a lifesaver for some and hopefully many more in the future:)

  • Interesting - thanks for that

  • Oh sweetie, I feel for you. GO TO STOPTHETHYROIDMADNESS.COM and you will find all you need to know for thyroid and adrenal health. Your FT3 should be at least mid range and your FT4 should be at the very top of the range. Also if you feel better by knowing where your TSH is then it should be suppressed near about 1 or less. I promise just go to that site and you will learn all you need to know. AND you will find out that doctors all over the country are stupid about thyroid. THEY have no idea where labs should be and they follow the ranges which are way way way too wide. SAY my TSH is 4 with the range being 1- 5, well they say OH YOUR FINE, well NO I AM NOT. DO you see what I mean? IT must be within a certain range and they have no clue. Please just go to that site. ALSO YOU NEED Armour not those drugs you are taking. Levox, Synthyoid, etc..... ARE ONLY BAD. YOU will remain hypo and sick. I hope this helps.. I had to research for years and finally found groups online to help me. Now, I know all of this.... and love to help others. GOOD LUCK,. YOur doc will not want to give you Armour.... so keep searching for one who will.

  • Update to my original question:

    This morning I had a most unsatisfactory consult with Lolin, the endo/pathologist.

    She said my thyroid results were OK! (TSH 0.5; FT4 14.6: FT3 2.9.) Just as well I’d got them beforehand! She wanted me to go back to just 75mcg T4/day. Despite me telling her I feel crap and the results are either right at the bottom of the ‘normal’ scale or below it.

    So now she wants me to carry on taking 50mcg T4 and 10 T3 a day. I persuaded her to go for 50 T4 and 20 T3. But as I understand it the ratio should be 5:1, and you should aim to be toward the higher end of the T4 scale and at least the middle of the T3 scale. So I was hoping for 100 T4 and 20 T3, at least.

    She’s worried my TSH is so low I could go toxic. Also that producing too much energy might be more than my body can cope with because of my chronic fatigue syndrome. This sounds like utter rot to me.

    She now wants me to do a TRH test (I haven’t looked it up yet) to test my pituitary function as she suspects secondary hypothyroidism.

    Well, I’m not happy with the thyroxine dosages, and I’m not happy with having to wait for a test that is probably irrelevant. Could be weeks. While I continue to feel rubbish. And I’m under instructions not to increase my thyroxine dosages or it will invalidate the test results.

    So, what does the team think? And what do I do next?

    I could try to get the test done privately to hurry it up – but then I’d have to go through all the palaver of drumming up a referral letter from my GP first (presumably), even though I’m already seeing Lolin on the NHS. I could up my thyroxine dose to 100/20 and see how I feel, then reduce the dose a few days ahead of the test, whenever that comes through.

    And that’s another thing. Lolin said you feel the benefits of increased thyroxine drugs within a couple of days. My understanding was that it can take weeks. So would reducing the dose a few days ahead of the test be early enough anyway?

    Or I could forget about orthodox approaches altogether. Certainly, I don’t feel any rapport (medically – she’s perfectly nice personally) with Dr Lolin, so I think I’d need to switch orthodox docs anyway – and to whom?

    I could go and see my naturopathic doctor and talk about NDT and forget altogether about Lolin and her TRH, at least for the time being. I could even maybe tell her I’m trying NDT first and that I’ll come back to her later if it doesn’t work out. Or maybe experiment with regular T4 and T3 with the naturopath?

    Or I could ferret out one of the ‘recognised’ non-orthodox thyroid practitioners and go there, and forget about the orthodox approach altogether.

    Advice gratefully received!!!

  • It is going to take some patience to get well. I think this doctor is trying to help and is sincere but believes what most doctors believe about TSH. The good news is that she wants to do further tests and check things out. I would stick with the regime she is suggesting for at least a month to see how it goes with the increased T3. Did she say about dosing? I am tempted to take it as a single dose early in the day at exactly the same time and see if you get an improvement and a good 'start of day'. It will show T3 is helping.

    If all this does not work then explain that you could be having problems converting T4 to T3 and be making reverse T3 (rT3) which blocks access of normal T3 to the cells, preventing energy. Say you want to reduce T4 and increase T3 until you are on T3 only to see if that works. rT3 can be tested for if she requires it.

    Each change takes a month to stabilise before you can honestly say 'It's not working' as other cycles in the body take time to adjust.

    T4 takes days to work and days to reduce. T3 on the other hand takes hours either way as it has a much shorter half life (decline time).

    Those are my thoughts.

  • Most test can be had privately without a referral, so if you want to speed it up you could have a look at the Genova and Blue Horizons sites to see if the test is in their catalogues.

    Have you been on t3 all along (sorry, I didn't see you mention your meds but this site acts up a bit on long threads so maybe I missed it)? It worked very well for me in combination with levo for about six months, and a lot of people find it helpful.

    Just as an aside, unless I've got the wrong end of the stick, I think admins may prefer that you don't name your endo (you can edit it to Dr L or whatever you like). :-)

  • Point noted about naming docs. Though it's a policy I don't agree with.

    I doubt Blue Horizon would easily be able to do the TRH test as it requires several blood tests at intervals after infusion of TRH to stimulate the pituitary. But I can look into it, thanks.

  • Re-reading my reply I should have said 'many' rather than most. You may be right, it sounds more complicated than the usual test. Good luck.

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