Why is my T3 low when on thyroxine?

[Charliixo]

Anyone know why my FT3 would be low (but still normal range) if I am on thyroxine? Does that mean I am not converting T4 to T3 very well?

Thanks :)

[Charliixo]

Thanks for your reply.

I did take B12 in the past but stopped as I did not feel much better.

I see my doctor tomorrow and I will ask at my appointment if I can be given a trial course of T3. I'm not expecting any joy...

[gimel]

Flyingfool is correct about your B12.  Your D is a bit low.  Your ferritin is way too low.  Recommended for women is 70-80.  Both D and ferritin are important to good thyroid function.  Low B12 can cause symptoms of its own.  I heartily recommend supplementing each   Start with moderate doses and increase as needed to reach optimal levels.

Looking back at your TPO ab and TG ab tests, they, along with everything else, indicate Hashimoto's Thyroiditis.  You should push your doctor to prescribe some T3 med for you and ask to be treated clinically by raising your Free T3 as necessary to relieve symptoms.

[Charliixo]

Thanks for your reply.

Doctor told me my B12 was fine and I did not need supplementation. I have always considered my symptoms to be related to the hypothyroidism and not the low B12 as my doctor said my B12 levels were normal.

[flyingfool]

Your Vit B-12 is VERY low.many countries such as Japan do not even start the lowest part of the range to be 500.  Many people do not feel well until their B-12 is well up in the range as in above 600 or 700 if not more!

[Charliixo]

Thanks for your reply.

I have been tested for antibodies in the past, once in December of last year where my Thyroid Peroxidase was 41 KIU/L (>34) and again in March this year where my Thyroid Peroxidase was 33.5 IU/L (0-34) and my Thyroglobulin at 103.5 IU/L (0-115). So is that Hashimoto's? I'm being told it is by one doctor and not by another.

Thanks for providing me with the link. I will look at this now.

If I was tested for ferritin, Vitamin D and Vitamin B12 back in December then when is the next best time to be retested?

[gimel]

Were you tested to determine if the cause was Hashimoto's Thyroiditis, which is the most common cause for diagnosed hypothyroidism?  Two tests are usually done, for Thyroid Peroxidase and Thyroglobulin antibodies.  Usually denoted as TPO ab and TG ab.

Assuming that the original diagnosis was correct, since you say you had hypo symptoms, and also a high TSH, then your doctor did the right thing in starting you on thyroid meds.  However, now that you are taking a T4 only med, your body is doing what frequently occurs, which is inadequately converting the T4 to T3.  As a result, your Free T3 level is much too low.   You need to add some  T3 to your med and gradually increase until you get relief from symptoms.

A good thyroid doctor will treat a hypo patient clinically by testing and adjusting Free T3 and Free T4 as necessary to relieve symptoms, without being constrained by resultant TSH levels.  You can get some good insight into clinical treatment from this letter written by a good thyroid doctor for patients that he sometimes consults with after initial tests and evaluation.  The letter is then sent to the participating doctor of the patient to help guide treatment.  In the letter, please note the statement, "the ultimate
criterion for dose adjustment must always be the clinical response of the patient."

http://hormonerestoration.com/files/ThyroidPMD.pdf

So, I suggest that you should read the link and that will give you some good  insight into the type of  treatment you should be getting.  You should ask your doctor to add some T3 to your meds.  You should also ask the doctor if he is going to be willing to treat you clinically, for symptoms, as described.  If not, then you will need to find a good thyroid doctor that will do so.  

One further thing is that hypo patients are frequently too low in the ranges for Vitamin D, B12 and ferritin.  All are very important for you to feel good.  If not tested for those, then you should request them.  

[Charliixo]

Thanks for reply. I was put on meds after my TSH came back high and I had symptoms.

[gimel]

Looking back at your FT3 and FT4 before starting meds, why were you put on thyroid med at that time?  Were you having symptoms at that time?  

[Charliixo]

Thanks for replying.

My daily dose of T4 is 125mcg.

FT3 result before T4 meds - 5.5 (3.1-6.8)
FT4 result before T4 meds - 15.6 (10-22)

FT3 result after T4 meds - 4 (3.1-6.8)
FT4 result after T4 meds - 16.6 (12-22)

Symptoms:

Depression
Dark/thick/painful periods
Splitting hair
Dry skin on arms and face
Depression/anxiety
Acne
Leg/knee/wrist/arm/back/shoulder pain
Headaches
Fatigue
Constipation
Difficulty swallowing
Itchy skin around neck
Weight loss (?)
Mood swings

Vitamin D - 44 (>75)
B12 - 360 (180-900)
Ferritin - 22 (30-400)

[gimel]

What is your daily dose of T4 med?  Please post both your Free T4 and Free T3, along with reference ranges shown on the lab report.  What, if any symptoms are you having?  Have you been tested for Vitamin D, B12 and ferritin?  If so, please post results and reference ranges as well.