Blood results

I have been on Levothyroxine(100mcg) for a few years now. I decided in February to introduce T3 to see I'd any of my symptoms improved. I am now on 50mcg of Levothyroxine and 50 of T3. My latest blood results have just come back and are as follows.

Serum free T 4. 9.00

Serum TSH. 0.01

Serum T3. 5.7

Do I need to increase my dosage?


4 Replies

  • Can you include the reference ranges? As they differ in different parts of the country, it's not possible to know where your results lie in their ranges so it difficult for members to comment. Also, if you include previous results prior to addition of T3 that will help to see what difference the T3 has made.

  • Tilly, more important, how do you feel? if your ranges are what the normal ones are your T3 looks good, but T4 low. 50mcg T3 seems like a lot to me.

  • Tillypops,

    FT4 is low because you are taking a proportionately higher dose of T3 than Levothyroxine. FT3 5.7 is usually good but without seeing the range it isn't possible to say whether there is scope to increase dose.


    I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.

  • T3 is the active thyroid hormone which regulates the metabolism and therefore the symptoms. If the ranges are the common ones in the UK, your free T3 in the top part the range you should not have any hypothyroid symptoms.

    T4 is the inactive form and needs converted to T3 to become active.

    If my guess about the ranges is right these results and if you have continuing hypo symptoms, they could be caused by thyroid hormone resistance, also known as impaired sensitivity to thyroid hormone. This is a genetic condition so if there are others in your family with fibromyalgia, chronic fatigue, depression or thyroid issues this would support this possibility. With this condition the body needs very high levels of T3, often above the top of the normal range.

You may also like...