Thyroid UK
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Feeling short of breath, related to T3?

Since Friday I've changed from taking 100mcg levothyroxine a day, to taking 50mcg levothyroxine (75 on the first day, but dropped it) and 20 mcg liothyronine.

Yesterday I felt great, alert, it didn't take me ages to wake up, no afternoon energy crash, an my eyesight seemed sharper. But tonight my breathing has been funny, a bit shallow, and my chest feels a bit constricted. All evening I haven't been able to focus on anything but my breathing. It's not bad enough that I need to see a doctor, but I'm concerned about how to progress. Should I take my usual dose tomorrow and accept that it will take time to adapt to the new meds? If I call my GP I think he will make me go back to levo and I was unwell on that so I want to persevere.

Should I go down to 10mcg for a few days?

6 Replies

I was onT3 only for many months and am now adding in small amount of Armour thyroid. I had that same tightness of chest and actually took myself to A&E. they did an ECG and all was well. Soon after that I found I had low ferritin and started iron tablets. Slowly I improved. T3 requires good levels of B 12, iron, folate, and Vit D to be tolerated. Have you had all these tests? It will help if you divide your dose into four. This is how I started. Cutting the tablets is a bit tricky but worth the effort. Gradually you can take more at each dose, maybe 10mcg, twice a day, once your body gets used to it. Hope this helps. It s a brilliant medication. Don't give up.


Thank you.I got my test results back last week, my ferritin was 21.1 (range 10-200) so I suppose that's very low? I wasn't tested for B12 or Vit D though I've been taking the recommended doses of both for about a month. I'll try the T3 in four doses tomorrow, thanks!


Your ferritin needs to be over 70, preferable nearer 90, before you body will tolerate and use of T4 and T3 properly - although trying to get a doctor or endo to admit to this is near on impossible. Here is a link that explain it properly.

As for food and T3 - a professor at a top London hosp told a lady from this site to keep T3 away from food just as you would T4. When I was on T3 I found a noticeable difference when I didn't keep my T3 at least an hour, preferable two hours, away from food.

Moggie x


Can I just ask, what is the food situation if you're taking four doses? Do you have to wait 2-3 hours to have an empty stomach each time? I'd have to be very regimented and set alarms on my phone!


Hi GO, here is the list of optimal labs and you can scroll down to see ferritin. You can be too low or too high (as I am), neither is good. Many people seem to feel you don't have to worry about whether you have eaten or not when taking your T3 pills but have not seen an article stating either way yet.


I had breathlessness, still have, but not as bad now.


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