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Thyroid UK
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Latest test results. High FT3

I have been self medicating T3 (Tiromel) for past 12 weeks now as my T3 was previously low at 2.5-2.8. I have been mediacting about 75mcg. This was increased slowly and pulse and temp taken as a measure to make sure wasn't overdosing. Temperature went from 35degreesc to 36.5degreesc and my resting pulse is 70 now. Since medicating symptoms have got a lot better and feeling more energy. Weight had been maintaining but not lost any.

Latest results are as follows:

ANTI - TPO 9iu/mL [<34.0]

TSH 0.01 mu/L [0.27-4.2]

FT4 13.2 pmol [11.0-22.0]

FT3 7.5 pmol [3.7-6.8] Above range

I can see my FT3 is too high so should reduce my T3 medication. Is it normal to have such a low TSH? My previous FT4 was about 14.

Any advice?

4 Replies


A low TSH & T4 is usual when medicating T3 or meds containing some T3.

T3 (taken on an empty stomach) is rapidly absorbed and reaches peak circulating concentration in about two to three hours after ingestion. A slight over range result during this time can be expected in some. What time delay did you leave between your meds & TFT's ? ?

Blood serum concentrations may remain elevated for six - eight hours after and T3 levels should remain within range during this time.

Are you multi dosing or taking the whole dose in one go ? ? ...


There was about 12 hours between meds and tests. I did not take medication in the morning or afternoon. & had my tests at about 2pm.

I have been multi dosing half morning and half in afternoon. I find that this makes me feel better through the afternoon. When I tried single dosing in afternoon I found I felt so larthargic and sluggish come 2/3 o clock.


Then I would say you are slightly over medicating & need to reduce.

Re weight loss, it is really important to eat well .... a healthy diet of regular meals. Allowing yourself to become hungry or consuming inadequate calories will compromise the HPA axis (hypothalamic-pituitary-adrenal) as without adequate nourishment, the adrenals will compensate and high/low cortisol levels will suppresses thyroid function and weaken the immune system.

The weight gain will shift when you are on the correct dose & the meds are working properly.

Are your nutrients/iron optimal ?


One thing I'd ask is how many weeks you held on one dose before this test. The rule of thumb is that you should wait 6 weeks. In pure T3 you may get away with a bit less as it's fast acting, but it still takes the body a while to adjust to a new dose, so I don't think anyone knows how much less you could get away with. If you didn't leave long enough, the test isn't really valid.

As Radd said, this test shows overmedication, so the standard advice is to drop the dose a little. Personally I am a little sympathetic to high doses, as it looks like I may need an over-range freeT3 to feel well. But I raised to that level over a two year period! I don't think you can feel at all confident what your needs will be after only 12 weeks.

That being the case, I think if I were you I'd hold on this dose for 6-12 weeks, to let your body really settle down and be clear what symptoms, pulse, temp, etc you will have at this dose. Then test again if you want to be super thorough, but if not then take stock and decide how to adjust the dose.

The reason I say this rather than advise an immediate decrease is that these hormones are a very slow acting thing. The worst thing you can do is jerk yourself around changing doses every few weeks, trying to chase a certain blood result. But many of us are tempted to do this because we want to be well soon. However if you really give this current dose a good trial and make excellent notes you will know exactly how you feel on it, and you won't ever have to try it out again to confirm whether it's right for you.

If you find that this really is an overdose for you, and all your signs and symptoms back up this blood test, then that is excellent news. You've really drawn a line in the sand and you know your ideal dose is lower than this. Then you can very slowly work backwards and start to close in on what the right does is. However there is a small chance that you might feel better on this dose than in any other. But you'll only know that by holding on it for some time and seeing how your body manages on it.


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