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4142235 tn?1350244719

FT3 Won't Budge

Been mostly very hypo with low-normal FT3 since diagnosed with Hashimoto's 2012 - Drs were terrified of low TSH. New Dr working on getting persistently low FT3 increased but so far not working. Each increase in Liothyronine makes me feel like my old self initially then things slide back to feeling hypo. The increases in T3 have not caused jitters or hyper feelings.

Have tried every variety of T4 and T3 synthetic and NDT.

Taking all of Synthroid dose (50mcg increments because it has no fillers) and 1/2 of Liothyronine dose at 4AM. Taking other 1/2 of Liothyronine at noon away from food etcetera.

4AM meds are postponed until after labs. Started adding T3 to the Synthroid about a year ago and have slowly ramped up the T3 with decreases in the T4. Now at 20mcg T3 split 4AM and noon but my T4 has dropped off the cliff and I'm hypo again.

Any ideas what could be going on?

7-25-2023 (50mcg Synthroid daily, 20mcg Liothyronine split)
TSH not tested
FT3 2.50 (2.0-4.4)
FT4 0.64 (.82-1.77)
Vitamin D 58.1 (30.0-100.0)
Glucose 93 (65-99)
Ferritin 66 (15-150)

5-9-2023 (100mcg MWF, 50mcg SS T&Th, 15mcg Liothyronine split)
TSH 0.092 (.45-4.50)
FT3 2.50 (2.0-4.4)
FT4 1.14 (.82-1.77)

1-10-2023 (100mcg Synthroid M-F, 15mcg Liothyronine split)
TSH 0.134 (.45-4.50)
FT3 2.20 (2.0-4.4)
FT4 1.03 (.82-1.77)

11-9-2022 (100mcg Synthroid M-F 50mcg S-S, 10mcg Liothyronine split)
TSH 0.043 (.45-4.50)
FT3 2.70 (2.0-4.4)
FT4 1.21 (.82-1.77)

9-8-2022 (100mcg Synthroid daily, 5mcg Cytomel split)
TSH 0.055 (.45-4.50)
FT3 2.60 (2.0-4.4)
FT4 1.53 (.82-1.77)

8-11-2022 (150mcg Synthroid daily)
TSH 0.307 (.45-4.50)
FT3 2.20 (2.0-4.4)
FT4 1.56 (.82-1.77)
4 Responses
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Avatar universal
I agree with Gimel as usual.

Question:  When you site the dosages for the test date.  Was that the dosage that you were on at the time of the test, or was that the recommendation at that date and the next test would indicate the blood levels from that dosage change?

It is almost imperative that you only make ONE dosage change at a time. That is change ONLY T4 dose, OR T3 dose, not both at the same time.  As it is harder to see what is happening if you change both at the same time.

I would highly recommend that you start with only changing (increasing) the T4 dosage.  I would further recommend that a consistent T4 dosage for simplicity for every day (7 days a week) makes sense if possible.  Increasing the dose so that you are at least 50% which would be a FT4 level of at least 1.3.   Gimels estimate for the total of about 650 mcg per week (100 for 6 days plus 50 Mcg one day ) makes sense.  it may take a bit more but you have to work with the dose increments available.  After you get your FT4 level to be mid range or a tad higher.  Then see where the FT3 level settles at and more importantly what your symptoms are like.

Please note: Any T4 dose takes about 6 weeks to stabilize.  as the half life is measured in WEEKS.  While T3 dose is nearly immediate with a half life measured in HOURS.  This explains why with each T3 increase in dose you feel well almost immediately, but the delay in the reduction of the T4 dose lags by a few weeks and over time you feel bad again.  This is why I recommend stabilizing and focus only on the T4 dose.  increasing your FT4 level should also help your Ft3 levels rise slightly due to conversion of T4 into T3.  There is still some room for your FT3 levels to rise most likely before you MAY start to feel Hyper.  If you do start to feel hyper, you can reduce your T3 dose.
Helpful - 0
Avatar universal
I expect the reason your FT3 dropped is the continual reduction in your T4 med.  In your situation, your T3 is  dependent on your T4 level, since the T3 has to be converted from T4, plus any T3 med.  When trying to eliminate hypothyroid symptoms, a good target for both FT4 and FT3 is mid-range.  Both have to be taken into account because they both affect symptoms.   FT3 directly.  FT4 because it is converted to FT3.   As your levels are adjusted toward those targets, you can determine the levels at which you feel normal.  

Looking at your test history, it seems your best level to try and get your FT4 to mid-range would be 100 mcg for 6 days and 50 for one day.  Along with that, I think it would be best to continue with the 20 mcg of T3, and see where both FT4 and FT3 are at next round of tests.  I expect that you will need further increases in your T3 med dosage, but you can best determine that by how you feel.  Be sure to give any new dosage some time to affect symptoms.  

Also important for you are Vitamin D, B12 and ferritin.  Your D is good.  I suggest testing for B12 and then supplementing as needed to get it into the upper third of its range.  Your ferritin is inadequate.  It should be at least 100.  Ferritin affects conversion of T4, and also when too low it seems to  cause unwanted effects when raising FT3 levels.  So I suggest supplementing with iron.  A good supplement would be Iron + C, available inexpensively from CVS.  One tablet, which contains 65 mg of iron, should be adequate.  If it affects your regularity, take as much additional Vitamin C as needed to alleviate.  

You can confirm what I have said by reading a link to a paper I co-authored.  Here is a link.  

Helpful - 0
gimel and flyingfool - thanks so much for your replies and explanation of T4 lag-time causing return to hypo symptoms - that checks out!

I had previously downloaded The Diagnosis and Treatment of Hypothyroidism: A Patient’s Perspective several years ago and now your other linked piece. Thank you!

Note: The medication dosages shown listed with my labs were current at testing and changed after labs.

My B12 has always been 'high' - last test was 1704 (232-1245) and has been over 2000. Dr not concerned. Only getting 400mcg B12 in multi-vitamin.

I will look at the Iron+C supplement. My primary Dr has said I don't need it because Ferritin and Iron are in 'normal range'... Ferritin 66(15-150) and Iron 92(27-129)

My FT3 has been low-normal for years no matter how high the T4 or T3 or NDT dosage. It has gotten to 2.7 twice otherwise usually bottom of range or lower. A decade of mostly hypo symptoms.

My FT4 was also most always low-normal (even on T4-only meds maybe undermedicated) until this past year of adjustments, and has since been at some higher readings until last lab.

Current Dr is trying to work on increasing FT3 and stabilizing FT4, indicating that the T4 dosage has to be decreased with additions of T3, as shown in labs info. But this has reduced T4 too much and Dr is now adding 50mcg back once per week in addition to 50mcg per day/7 days. Keeping T3 at 20mcg per day/7days. Testing again in 2 months. As gimel noted, may need to add more T4 than that to get FT4 back up.

This sure is a long process...
If your ferritin was at 16, would the doctor think that was also okay?  The breadth of the range  (15-150) is ridiculous.   It is not functional for patients at the lower part.  A lab range is based on their database of results.  How would they know what is adequate?   It is just a range based on actual results, a lot of which are inadequate.

There is scientific info suggesting that it should be at least 100.   I have personal knowledge of people having unwanted reactions to raising their T3 med dosage when their ferritin was too low.   So I would just take the supplement and not involve the doctor on that again.  

Also,  there is no need to automatically lower T4 dosage, when adding T3.  Everyone can be different in their best levels, and you  need both to be adequate.  Mid-range is a good target to get to and see how you feel.  Along with that you want to be sure to keep your Vitamin D at least 50 ng/ml, and ferritin at least 100.

Other than that my recommendation stands regarding your daily dosage of T4, and then after next round of tests add T3, with objective to  get to mid-range and see how you feel after some time for adjustment.    For caution, be sure to start supplementing iron before adding T3
Thanks gimel - I agree that the Drs strict adherence to lab ranges despite the patient sitting before them is a menace...

I found the iron+c to try and also wondered about the value of selenium - noticing there is none in my multi-vits?
I would not add selenium unless you continue to have conversion problems after getting your ferritin adequate, and also only after a test for selenium to know your level.

Son't forget if the Iron supplement causes any problem with constipation, just add Vitamin C as needed to alleviate.  
Thank you for providing your insights and suggestions - very much appreciated :-)
Avatar universal
Also, when you say you feel hypo, what symptoms do you have?
Helpful - 0
Avatar universal
First thing I would like to know is whether you take your thyroid med the morning before the blood draw.  Also were the blood draws all done about the same time of day?  the reason I ask is that thyroid med should be delayed until after blood draw, in order to prevent fals high results.  This is even acknowledged in the AACE/ATA Guidelines for Hypothyroidism.  
Helpful - 0
Thank you - yes, I always postpone thyroid meds until after labs. The hypo symptoms are dramatically different from when I feel 'normal'. Excessive lethargy, crashing mid-day needing nap, lower back ache, slow innards, all over slow feeling. All of these disappear for a while after increasing the T3 but then hypo creeps back in as evident in the labs...

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