Thyroid UK
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blood test

Hi just looking for some advice I have been taking 25mcg of levo for about five weeks and am due to go for a blood test at the end of the week, just wondering what they will be looking for, I was originally put on 50mcg but found I was having headaches and nausea so GP suggested the 25. she was putting me on it as a trial as she said my results were within range but as I had the symptoms it was worth a try. to be honest I dont really feel any better.

3 Replies

Ann, don't take your Levothyroxine until after the blood draw as it will skew the results. If GP just tests TSH s/he will be looking for a lower TSH. If FT4 is also tested it should be higher.

25mcg is unlikely to have been much use. Now your body has adapted to it you may be able to tolerate 50mcg without headaches and may see some improvement in symptoms.


thank you do you think I should start taking the 50mcg as I have still got them, I dont know if it is just me but when my pack of 25 finished and I started the new ones which are a different brand I started feeling a bit off is this common as they are the same strength.


Ann, I'd wait until after your blood test before increasing. If you get headaches try 25/50mcg alternate days for a week or two before increasing to 50mcg daily.

Different brands can cause upset due to different fillers or formulation. Tell your pharmacist which brand you prefer and ask him to mark your notes to that effect.


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