Thyroid UK
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Low FT4 With Normal FT3 and TSH?


I’ve had my most recent blood test results through, and I was surprised to see that my FT4 is so low in the range. Does anyone know why that might be? I take 2.5 grains of NDT and I skipped the morning of the test.

TSH <0.05

FT3: 6 (3.1-6.8)

FT4: 11 (11-22)

I am still experiencing Hypo symptoms, although I'm also diagnosed with ME so it's difficult to know what's down to the ME and what's down to the thyroid.

Can I top up my NDT with a small amount of Levothyroxine? The Endocrinologist who has recently discharged me because I chose to take NDT told me I shouldn't, but I would welcome any input from you.

Thanks for any replies.

10 Replies

FT4 is usually low when taking NDT. It's FT3 result that matters.

NDT should be left off for 12 hours before blood draw.

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Thanks, SeasideSusie.


The blood tests were introduced along with levothyroxine (T4) so if we add in other hormones, i.e. either adding T3 or taking NDT - results cannot correlate with T4 only. If you take NDT, and are having clinical symptoms you can add 1/4 of 1 gr tablet every two weeks until you are symptom-free.

I will say I am not medically qualified but had undiagnosed hypothyroidism.

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Thank you, shaws.

When you say add 1/4 of 1 gr tablet, do you mean NDT or T4?

I've been having some symptoms recently which are making me think I might be over-medicated, namely hand tremors/shakes and pulsatile tinnitus (a rhythmic pumping/whooshing in the ears in time to the heart). I'm still extremely fatigued, lethargic, and often have cold extremities. It's almost like I have symptoms of both hypo and hyper which is making things very confusing for me.

Thank you.


I am only talking about NDT not levo. you've not had thyroid antibodies checked ask for these at next blood test if you haven't had them checked previously. It could be due to antibodies flooding out and making you feel hyperthyroid when you are really hypo. I shall give you a link re Hashi's which is an Autoimmune Thyroid Disease - the commonest and due to having thyroid antibodies.


Thank you. Last year my TPO came back as 1017u/l, so I know my Hypo is autoimmune related. I haven't had it tested since as getting my Endo to agree to the initial test was a nightmare. When it came back so high, I asked him about it and he basically shrugged it off and didn't really comment.

I'll have a look at the links you've provided and I'll try adding another 1/4 of a grain of NDT to see how I get on. Thanks again.


It is a struggle and they are so poorly trained and really aren't aware of how we feel, considering all of the different symptoms one can get and they know none. Once upon a time we got diagnosed due to our clinical symptoms alone, no blood tests or levothyroxine then. We were prescribed NDT and increased dose until we felt well with relief of symptoms. If pulse/temp rises drop to previous dose.


The emphasis when taking thyroid hormones is all about how we 'feel' on a certain dose. The aim is to feel better with no clinical symptoms. Doctors seem to believe if we have a very low TSH we will have heart or bone problems but not if we are on an optimum for us individually and feel well.


Thank you, shaws. You've been really helpful.

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This is a list of clinical symptoms of hypo:

This is about antibodies:


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