Thyroid UK
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Advice please

Hello, I'm new here.

I have been treated for hypothyroidism for the past 8yrs.

I am on 125mg Levothyroxine daily.

Last week I had a blood test.The thyroid levels are as follows:

Serum TSH Level 0.16 miu/L

Serum free T4 level: 20.3 pmol/L

I feel well and yet I have been asked to make a doctor's appointment because of this result.

Can anyone advise as to whether I need to have any alteration at all to my present doseage

of 125mg levothyroxine?



4 Replies

Hello Jean,

If you feel well, this is obviously the right dosage for you. A TSH in the lower part of the reference range and a FT4 at the upper end is what most hypothyroid patients aim for with thyroid hormone replacement . There is a little booklet called 'Understanding Thyroid Disorders' by Dr Anthony Toft usually available in pharmacies which might be helpful if your GP decides to lower your dose which wouldn't surprise me. They tend to panic on seeing a 'low' TSH and then advise you to drop your dose.This causes unecessary suffering and naturally you'll want to avoid that.


Hi I agree. The key is you feel well. You will still need repeat tests as lots of things effect the thyroid. You may need dosage altered in time. Also if you do have more problems try to get the Free T3 tested as often we also need T3 on a script. For now I should just rejoice that all OK for you. Do keep test results as that is vital.



This is an excerpt from Dr Lowe who was an adviser to

The TSH level is not well synchronized with the tissue metabolic rate. (Probably most doctors falsely assume that studies have shown that the TSH and metabolic rate are synchronized. But despite my diligently searching for years for such studies, I’ve yet to find them.) Adjusting the T4 dose by the TSH level is like adjusting the speed of your car by a speedometer that's out of synchrony with the actual speed of the car. Adjusting the speed of a car by an out-of-sync speedometer, of course, will get the driver into trouble—either with other drivers who'll object to the car traveling too slowly, or with a police officer who'll object to the car going too fast. And adjusting the thyroid hormone dose by the TSH level gets most patients in trouble—almost always because their tissue metabolism is so slow that they are sick.


Hi Jean

As everyone says, the GP is most likely going to ask you to reduce your dose to 100mcg daily. However, as you feel well, you don't want to do that. This happened to me, and I have suffered rather badly from it, and now have some permenant nerve damage as a result. I would strongly advise that you try very hard to stay on your current dose. Perhaps suggest that the GP checks with an endocrinologist as you feel well and don't feel overmedicated. If you are unable to resist a dosage reduction, make sure that the GP agrees to check your levels within 6 weeks, and ideally again after another 6 weeks, to make sure there isn't a steady decline.

Good luck



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