Taking T4 and still having hypothyroid symptoms would T3 help?

My TSH is low and my T4 in the upper range but my T3 is barely in the lower end of the range and my GP says I am adequately replaced however I feel awful. I was diagnosed 13 years ago and have been up and down over the years but worse since having children now aged 5 and 3. My Dr refuses a trial of T3 and referred me to an endo but having seen the referral letter she has made it sound that my treatment is optimised and the consultant has cancelled my appt. I was wondering if I should self medicate and have purchased Cynomel. I am taking125mg levo and wondered how much Cynomel I should take, I was thinking of reducing T4 to 100mg and taking 5mg of T3 twice daily, does this sound right? My T3 was higher a couple of years ago and I was able to loose weight, I am now gaining weight with 1250 calories per day and exercise 5 days a week. Help please !!!!

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24 Replies

  • Yes, Hemm, reduce T4 by 25mcg and take 5mcg T3 twice daily. 20mcg T3 is roughly equivalent to 60mcg T4 ncbi.nlm.nih.gov/pubmed/204...

    Adding T3 has been hugely beneficial for me and I hope you find the same.

  • Can I ask-do you have to take T3 on an empty stomach and avoid certain foods like with T4?

  • It's a good principle to take all thyroid meds on an empty stomach but I think it is less critical with T3. I will be looking for links on this as I didn't bookmark them at the time of reading. I wasn't aware certain foods had to be avoided with T4 and if its taken with water on an empty stomach food avoidance shouldn't be necessary?

  • Sorry-I didn't make myself clear, by certain foods I meant anything with calcium in it. I take my levo at night because I felt it was too much hassle trying to avoid calcium at breakfast. I am going to push for T3 next time I see my GP but always wondered how I would manage to take it on an empty stomach twice a day...my stomach isn't empty that often :-)

  • That's the problem with split dosing :( If you're thinking of fitting a dose around cups of tea or coffee half an hour either side might do but there is the chance that the T3 will be less absorbed and therefore less efficacious.

  • Ah well...I haven't got it yet of course so I'll put it on the back burner to worry about when that glorious day comes!

  • You can still take T4+T3 at night, so only one drink & food free slot to find in the day for the 2nd dose :)

  • Ah right-didn't realise you could take them together. Thanks :-)

  • Hi Clutter I read previously (cannot remember from who) that 20mcgs was equal to about 100mcgs T4? I have tried to read your link but cannot find where it states the dosage equivalent

  • There is a range of opinion on whether the ratio is 3:1, 4:1 or 5:1. 3:1 feels right to me. I was switched from 60mcg T3 to 200mcg T4 post RAI so I always assumed 3:1 to be the ratio. From ncbi.nlm.nih.gov/pubmed...


    This is the first study addressing the equivalency between L-T3 and L-T4 therapy measured by baseline and TRH-stimulated TSH. The therapeutic substitution of L-T3 for L-T4 was achieved at approximately 1:3 ratio.

  • Thanks for that Clutter. At present I am now taking 50mcgs Levo (reduced down from 100mcgs by Endo) and 30mcgs T3 upped from 20mcgs to 30mcgs by Endo. So what would you say that the total amount is that I am taking based on your 1.3 ration?

  • Marmaris, 3:1 ratio means you're taking the equivalent of 140mcg of Levothyroxine.

    4:1 would be equivlent to 170mcg and

    5:1 would be equivalent to 200mcg.

  • Thanks for that

  • Thank you so much

  • I agree with Clutter but you should also check your serum iron and ferritin levels, as you will not be converting T4 to T3 if these are low. Your GP should do these and maybe ask for B12, Folate and Vit D as these are often low in hypo people, which makes matters worse. Having children is a huge drain on iron and you mention you are worse since then. Hope T3 helps you.

  • Thank you. I have already started to take T3 so will that effect the results of these tests? Is it worth taking a B12 supplement as well?

  • T3 won't affect tests for ferritin, vitD, B12 and folate. Don't supplement B12 until after you've tested as it skews the results.

  • If your t4 is at top of the range and t3 is at the bottom of its range it should be obvious to any medical person with half a brain that you are unable to convert the T4 in thyroxine into the t3 your cells need to function

    Has Ferritin



    been tested because they need to be above halfway in their ranges or your body cannot do the conversion needed

  • Exactly I am so frustrated and just get really upset when trying to convince my GP I have now given up and am self medicating but it is trying to get the medication to ensure I can continue taking it. I am worried about buying it online as I am not sure what I would be buying even it is labelled T3. No I haven't had these tests done, my GP seems totally clueless, she won't even listen or let me finish my sentences. I was going to seek another opinion but I am sure they all confer and it seems like I would only get myself more upset and be no further forward.

  • What would you need to take to improve Ferritin and Folate? thank you

  • Ferritin is stored iron, so you need iron tablets. Folate is folic acid usually but I think there are other versions of the supplement too.

  • Thanks Clutter, i am so pleased to have found this resource. I just wish I could have convinced my GP to have prescribed t3 and not have to self medicate.

    There is a petition to try to get further testing for t3 on Mary Shomon's Facebook page

  • Can you sign and share this TUK petition, Hemm? epetitions.direct.gov.uk/pe...

  • I have done already Clutter, thanks

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