Hi there I've been taking t 3 only for about 3-4. Weeks and I felt amazing at first !! I was taking 100mg thyroxine and 2 grains of NDT previously . The reason for trying T3 only was recent blood test results showed poor conversion. I started low and increased slowly and I am now taking 2 x 25 mg T3 .daily . at first I felt great and my energy levels great brain fog disappeared no constipation . 3 weeks on I'm feeling tired and am suffering with constipation quite badly !! Do you think I'm taking enough T3 or should I introduce my NDT again ! I haven't been constipated for years and I'm not liking feeling like this again ! I haven't got any results at the mo as I thought I would wait a while before doing them again ! Any advice please 😉

9 Replies

  • I take a lower dose than you but that is really irrelevent as we are all different. When you take your second dose, is your stomach completely empty as food can affect uptake and do you also leave about an hour after taking it.

  • Just re-reading your question. Do you mean you are taking two 25mcg (50mcg) twice daily = 100mcg of T3.

  • I'm taking 25mg am and 25 mg afternoon so 50 mg a day ! I looked at a conversion chart for the amount of thyroxine and NDT I was previously taking and it said 75 mg was the equivalent . Do you think I should increase again ?

  • Thank you. I am not medically qualified so cannot advise but your dose of 100mcg and 2 grains would have been about 300mcg. This is another conversion chart.


    I don't split my dose of T3 and I shall give you a link for the reason. Once daily suits me fine. This is a link which I think you will find helpful if self-medicating.


    Go to date December 17, 1997 on the following:-


    I hope you get to a plateau of good health soon.

  • I don't think you are taking enough T3. One grain of NDT is equivalent to about 65mcg T4 (although some people say the equivalence is closer to 100mcg T4).

    If you take the lower figure, then you were taking a total of 100mcg + 65mcg + 65mcg = 230mcg T4.

    If you take the higher equivalence figure then you were taking the equivalent of 300mcg T4.

    50mcg T3 is equivalent to between 150mcg - 200mcg T4 depending on whether you believe T3 is 3 times or 4 times more potent than T4.

    Even if you assume that your old dose is equivalent to 230mcg T4, and you take the higher figure for what your T3 is equivalent to (200mcg T4) then you are under-dosing yourself by a fair amount.

    If you were to take the other figures I've suggested i.e. that you were taking the equivalent of 300mcg T4 but are now taking the equivalent of 150mcg of T4, then the gap is enormous.

    In either case it seems that you are still under-dosed and must continue to raise your dose.

  • Thanks will try this ! I've been gradually increasing but was getting a little worried I may take too much !

  • I just edited my second sentence. I had screwed it up quite a bit. ;) Doesn't change the meaning of the overall post though.

  • When I started T3 only I'd go months or even a year on same dose then bloods were changing and I was advised to change it very slightly as it is sensitive so maybe do 5 days a week of 2 x 25 then reduce it slightly at the weekend. He called it fine tuning but I'd check with a doc. I'm back on my regular dose now. Not sure why it did that.

  • Sorry just read some more. Also I wouldn't take it in divided doses. I did that once when I moved to another country on new docs recommendations and was so flat and went back to full dose in morning. A lot of docs are worried about side effects but don't understand the drug. They might be worried about your heart rate increasing etc from one dose but if you feel ok then check and go with one dose

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