Thyroid UK
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Blood results

Hi everyone. Got my blood results this morning. Before I started taking NDT I was on Levo. My FT4 was 16.6 and TSH .70 - as usual NO FT3 done, but I was battling with weight, was on anti-depressants etc etc. A friend gave me anough NDT for a week and I had the bloods done again.FT3 6.5 FT4 13.5 and TSH0.33.

The latest results are: FT3 4.4, FT4 9.0 and TSH 3.7. So looking at all that, the TSH has gone up and the other two down. I take 1 3/4 pills spread over the day of Thiroid.

My GP said that I need to watch my FT3 - this wasn't an issue before as the Levo only supplied T4. I aim to get to 3 pills but it needs to be done slowly as I discovered when I went too fast and my heart started to tap dance.

Any comments would be very helpful.

Many thanks.

4 Replies

Hi LizbethT

One week is too soon to have a blood test when you switch from one thyroid hormone to another.

Usually, six weeks is around the time you should have a blood test because the levo would be out of your system more or less by then and the NDT would be taking over.

The blood tests we have are for the use of levothyroxine only because if we take NDT containing T3 the T4, the T4 will be lower and the T3 higher and the TSH low.

Also if you are splitting the dose of Thiroid it will be difficult to leave a 24 hour gap between your last dose and the blood test. You should also fast and have the earliest appointment so the results aren't skewed.

When you give your results it is helpful if you put the ranges too as labs differ and it makes it easier to comment.

I admit it is a big puzzle at times trying to figure out things but I am sure the T3 in NDT will be of benefit to your because T3 is needed in all of our cells, the brain has the most and sometimes we cannot convert levothyroxoine (T4) into sufficient T3. Some Psychiatrists also prescribe T3 for their depressed patients.

I would wait another few weeks to see if you improve on Thiroid and you can raise- you don't necessarily have to have another blood test but only if you're having symptoms. I note you want to get to 3 pills a day but you might find that you may not need as much as 3.

You can raise your initial dose after two weeks. I would by a 1/4 tablet and this is a link which might be helpful. The best way to judge our dose is by how you feel.


Hi Shaws. Thank you for replying.

Sorry, I wasn't very clear. I took the NDT for a week and then tested to get a base-line for comparison.

I have been on NDT for nearly 8 weeks and had new bloods done with the results as given.

The lab used:

3.50-6.50pmo/L for FT3 - my results were 4.4

9.0-24.00 for FT4 - my result was 9.0

0.35-5.00mu/L for TSH - my result was 3.7

From what you have said I can presume that I need to increase by the final 1/4 up to 2, which I will do tomorrow as that is when it is due. I had to drop back from 2 because of heart beating too fast. I will take it slow and see how I go. But BP has dropped considerably as has my pulse and I don't have any shakiness either.

I am waiting for cortisol test results to come back so that also could have a bearing on the new blood results.

Am I reading it all correctly?


Yes, you are reading correctly. Most of us feel best with a TSH of 1 or below but some feel fine on a slightly higher result. Going by how we feel is the best rather than results.

Two links which might be helpful:



Just on comparative blood tests - I take NDT and my T4 is always tanking at the bottom or slightly below the reference range but my T3 is in the upper end of the range and my TSH below 1. So, don't worry too much about your T4 reading concentrate on your T3 and TSH reads.

Also work out how you feel; after taking NDT for around 3 months I had a huge improvement in my symptoms, I've now been taking it for nearly a year (since Sept 2014) but about 3 months ago I started to put on weight, started to have the 'I'm too knackered to move/speak/function' thing on a sporadic basis and my hormonal migraines came back. Got tested, my T3 had dropped and my TSH was back over 1 so got my dose upped by another 1/2 grain (Naturethroid) and am now stable in the weight dept and symptoms have again gone.

What I would say is now, nearly a year after starting on NDT (after a year on thyroxine which made me better than I was but didn't make me well) other things are starting to normalise and I feel the best that I have in 10 years. Now just need to tackle the 4 stone that I put on my tummy and all will be good :-)


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