Thyroid UK

Blood tests and dosages

I was diagnosed with hypothyroidism last Aug after having a blood test for neck pain. The results of the blood test were TSH 36.5 (0.4-5.5) and T4 7.6 (10.3-24.5) . I was started on Levothyroxine 100 mcg for 3 months I had a few symptoms on this palpitations, occasional diarrhoea but felt generally ok. When my blood was checked after three months my result was TSH 0.01 T4 21.1 (10.3-24.5) my doctor then put my dose down to 50mcg. Had another blood test 3 months later and the results were TSH 3.51 (0.4-5.5), T4 14.8 (10.3-24.5) the doctor seemed happy with the levels so kept me on this dose,I was told to have a blood test done in a years time.

I was fine on the dose to start with, joints were better, energy levels up, sleeping better. Decided that I would try the intermittent fasting diet or 5:2 diet to loss some weight, which started to work. Was even thinking of taking up jogging again. Then a few more weeks later started to have a return of symptoms joint pain, tiredness the weight stopped coming off. Got in touch with my GP and asked if I could have my levels checked. The results from this blood test were TSH 2.55 0.4-5.5) T4 12.6 (10.3-24.5) which he seemed happy with.

When I had my blood tests done I did not take my morning dose of Levothyroxine before the blood test and am unsure if that was the correct thing to do? I can't help but worry that a year is a long time to go before being re tested. Has anyone got similar levels and what dose medication has the doctor prescribed? I am also wondering if maybe the intermittent fasting might have maybe not been such a good idea from the nutritional point of view.

Any comments and advice would be welcome. Thanks in advance.

6 Replies

The problem with doctors, they use the TSH as a diagnosis and ignore patients clinical symptoms. Dr Toft of the British Thyroid Association says:-

Dr Toft states in Pulse Magazine, "The appropriate dose of levothyroxine is that which restores euthyroidism and serum to the lower part of the reference range - 0.2-0.5mU/l. 's

So you will see that your GP shouldn't have adjusted your medication just to get your TSH within range and you did your blood test properly by missing your morning dose until after the blood test. They also don't understand metabolism and this is an excerpt:

"Dr. Lowe: First I suggest that you ask your doctor to question the scientific basis of the endocrinologists’ notion of "fine tuning" by TSH and thyroid hormone levels. If he does, he’ll learn that the changes he sees in your TSH and thyroid hormone levels are probably nothing more than natural variations in the levels. He would probably see the same variations if he always kept your thyroid hormone dose the same. I’ll briefly review some of the evidence that your doctor should read."

Go to answer dated July 15, 2006 to read the question/answer.


Thank you for your reply. I'm glad I did the right thing when I missed my morning dose before my blood test. Very interesting article. I think a visit back to the GP.


You were right not to take your morning t4. But really I would have expected your doc to have taken a lighter touch with adjusting your dose, esp after you began to feel well. If you became a bit hyper on 100 (diarrhoea) it looks like you'd want to be on something like an alternating dose of 75/100 to see how you do on that. But to reduce to 50 is a bit over the top.

You may want to suggest to gp that if you're meant to be within range, can you try a higher dose which will keep you within range because you felt better on more meds, and now you feel ill. If you don't get any help, I'd change doctors. You could eventually try some t3 but if you feel well on levo it seems unnecessarily complicated to go down the t3 route.


Thanks for you reply, yes a appointment at the GP I think. I have some 100 tablets left over, might try quartering them and taking them with the 50mcg and seeing if 75mcg makes a difference. I have already considered changing doctors, not just because of the thyroid problem simple because there not a very good surgery.


Hi Orchid,

I agree with the others that the drop from 100 mcg to 50 mcg is a bit brutal. When my results came back similar to your first figures, though FT4 was over range, my GP recommended initially dropping to 100/75 mcg on alternative days and when after 6 weeks there hadn't been much change I went down to 75 mcg. My results do bob around a bit within the ranges and while my GP says they are fine, fortunately he also goes on how I feel. I have had similar TSH as your other results but FT4 is usually higher.

Puncturedbicycle gives good advice on what to suggest to your GP.


Thanks for the reply, yes you would think that they would be more inclined to go on how you feel. I certainly don't want to go a whole year before another test. I will see if I can try 75 mcg and see if it makes a difference.


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