T3 levels - my recent results

I have now got my most recent test results back and I am awaiting an appointment with the nhs endo.

Serum free T4 level - 17.6 pmol/L

Serum free triiodothyronine level - 4.9 pmol/L

I am anxious to take T3 due my vast weight gain and generally feeling poorly than I ever have! I have a lot of swelling around my whole body, but mainly my chest, neck, tummy and face. But my lower legs and ankles are slightly swollen too.

I have been reading that your T3 level should be high or over-high in order to work (from an American website Hyperthyroid mom) so I think mine needs to higher to work properly.

Can I self-medicate? Although, I would be happier doing it with my GP blessing, but he says to leave it to the endo.

I haven't had any B12 injections but I do take a strong vitamin B compound and thiamine tablets due to long standing disorder.

I feel very confused, alone and upset and really don't know how to go about getting some answers, it all seems like lots of information that I don't understand.

Thank you to all of you who take the time to read and reply to this, it is a massive help.

11 Replies

  • Bellerin,

    Do you have the reference ranges for FT4 and FT3 and what is your TSH result? 

    FT3 4.9 is usually near the top third of range considered desirable so you may not feel much benefit from adding T3 to Levothyroxine.  If you do self-medicate you should aim to keep FT3 within range. FT3 over range for a long time increases the risks of atrial fibrillation and osteoporosis.


    I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.

  • The range on my bloods was 3 - 7 for T3 and my TSH was 0.14, I really thought that T3 would help me, I am so desperate I've put on 3 and a half stone on overall and feel the worst I have ever felt. Am I so depressed, it scares me.

  • Bellerin,

    Adding a little T3 to Levothyroxine will raise FT3 and may improve symptoms but FT3 4.9 is good so it is debateable whether you will feel much benefit.  T3 can improve depression so it may be worth trying.

  • I don't feel that the levothyroxine has made any difference at all, in fact I feel worse than before! So thought I could just take all T3, or NDT? Other than the two things you mentioned, is it not worth trying to get my T3 level high, it get the weight off and feel better and then decrease, as to not have the long term effects? Thank you for replying.

  • Bellerin,

    Over medicating Levothyroxine &/or T3 can cause weight gain as well as the issues I mentioned above. 

    Most people add some T3 to Levothyroxine to see whether that improves symptoms before switching to T3 only.

  • So is my best option to stay the same on my levothyroxine (75mcg) and try just 25mcg of T3 to see if anything improves?

  • I am actually suffering from an eating disorder, and have been for about 8 years, could this also be a factor?

  • So do you think that in order to sort my weight out (ive put on 3.5 stone on overall), I should stop the levo medication & try T3? Bear in mind, I wasn't underweight when this 3.5 stone went on, so taking it back down would jeopardise my health. Thank you

  • Thank you so much, I feel very lost at the moment, really thought the levothyroxine would make me feel better and stop the weight problem.

    I am thinking very strongly about T3, do you think I should self medicate and just start at 25mcg? Can I take this along with my Levothyroxine?

    Is there a certain test that an endo can do to check if I have thyroid resistance?

    Again, thank you so much for your advice.

  • How would I find that? I would like to read that if I could.

  • Thank you

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