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Thyroid UK
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Levothyroxine dosage

Hi everyone, please can someone help me? I'm seeing my GP next week and would be grateful for some advice as to what to ask for in regard to increasing my dose of levo. I don't think he will be keen to up my dose now that my TSH is in range.

I was diagnosed with "subclinical hypothyroidism" on 2/08/17

TSH 8.8 mu/L [0.3 - 5.5]

Serum free T4 12.6 pmol/L [10.0 - 19.8]

No treatment given, retested 6th October

TSH 6 mu/L [0.3 - 5.5]

Serum free T4 11.3 pmol/L [10.0 - 19.8]

Prescribed 25 mcg levothyroxine


TSH 5.4 mu/L [0.3 - 5.5]

Prescribed 37.5 mcg levothyroxine


TSH 3.0 mu/L [0.5 - 4.4] - (NB note new reference range!)

The note from the lab says my treatment is adequate based on these results. I was going to push for a 25 mcg increase but now I'm not sure. Should I accept another 12.5 mcg increase? What would you do? The discomfort at the front of my neck has almost completely gone, just occasionally recurs. Otherwise still feeling cold and tired all the time. Constipation has improved a bit tho still not good.

I have no idea what to do and know that my GP knows even less than i do. I would be so grateful to receive some advice.

Thank you for taking the time to read my post.

Best wishes


4 Replies


You are undermedicated to have TSH 3.0. Ask for a 25mcg dose increase.

The goal of Levothyroxine is to restore the patient to euthyroid status. For most patients that will be when TSH is 0.5 - 1.0 with FT4 in the upper range. FT4 needs to be in the upper range in order that sufficient T3 is converted. Read Treatment Options in thyroiduk.org.uk/tuk/about_... Email dionne.fulcher@thyroiduk.org if you would like a copy of the Pulse article to show your GP.

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Thank you so much, Clutter, for your quick reply. I do look at other questions and answers before posting but was a bit surprised that such a small increase as 12.5 mcg of levo had such a significant effect. I will ask for a 25 mcg increase this time. Hopefully my GP will cooperate.

Another thing that concerns me is that the lab says on the results sheet that there is " no biochemical evidence of primary thyroid disease" and mentions a possible need for "further tests If there is any suspicion of pituitary disease". They have only tested TSH levels since I started taking Levothyroxine. Do you think I should be worried? Will point this out again to my GP and see what he says. He didn't really respond last time. I am actually losing faith in doctors and wonder if he will in fact know what It means.

Sorry to be a nuisance. It's just so scary having to work out the best thing to do when the GP seems to have no idea. Thank you so much for all your help, Thyroid UK is such a lifeline for so many of us!




Sounds like a generic lab note rather than a note specific to you. High TSH indicates primary hypothyroidism. This is usually caused by autoimmune thyroiditis (Hashimoto's). If they're only testing TSH and haven't tested thyroid peroxidase antibodies they cant know whether or not you have Hashimoto's. Neither can they tell whether there is indication of pituitary disease unless they test TSH and FT4 together. Low-normal TSH and low FT4 at diagnosis would indicate secondary hypothyroidism (pituitary dysfunction).



Thank you so much for that! I can see now that you are very probably right when you say it's likely a generic note. One thing less to worry about!

I am really grateful for all your comments. I will ask for thyroid antibodies to be tested. Don't know whether the GP will agree but will have them done privately at a later date if I have to.

Thank you again for your help.

Best wishes


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