TSH indicates hyperthyroid but FT4 and FT3 are low . I would love some insight

[SunSuzan]

I am a 60 year old female with hashimoto's. I have been working with an endocrinologist with the goal that stabilizing my thyroid would help with brain fog and fatigue issues, however I still don't feel great. The Endo is working on reducing my thyroid medication doses because he says I am "hyperthyroid " and his concern is that the suppressed TSH will make my osteoporosis progress

Current medications:
Synthroid 62.5mcg (half of 125 tablet) once daily
Cytomel 5mcg 3 times a day

Feb 2024.                                                        
TSH 0.05 mu/L (.32-5.04)              
FT4  8.7 pmol/L (9-19)              
FT3  2.9 pmol/L (2.6-5.8)          

I did not take Synthroid on the day of the blood test and my previous cytomel dose was 24 hours earlier

Ferritin 76ug/L ( 15-247)
Iron 34.2umol/L (10.6-33.8)
Iron Saturation .63
Vitamin D 80nmol/L (75-250)
B12 459 pmol/L (153-655)

Did I falsely lower my FT3 because I took my prelab cytomel dose 24 hours before my blood test?
Could my diminutive thyroid gland be impacting the conversion of T4 to T3?
Is my TSH too low for someone with osteoporosis ?

Thanks

[gimel]

Your Endo is doing you no favors.  He is following the erroneous belief that a low  TSH always means thyrotoxicosis (too much thyroid hormone).  But how can that be the case, when your FT4  is even below range, and your FT3 is only at 9% of its range.  Obviously that is not "too much thyroid hormone.  

The problem is that the ATA/AACE Guidelines for hypothyroidism say that thyroid medication dosage should be adjusted as needed to keep TSH in range.  They don't acknowledge that taking thyroid med changes the relationship among TSH, FT4 and FT3.  They also haven't yet acknowedged that a TSH in range does not always mean the patient is symptom free.  Many patients find that relief from hypothyroid symptoms requires FT4 and FT3 to be high enough in their range, that it often results in suppressed TSH.  

A suppressed TSH will not make your osteoporosis progress.  Bone loss is not associated with TSH, but is is affected by excessive thyroid hormone levels, which you do not have.  For info I ws diagnosed with osteopenia/osteoporosis in the hip area about 3 years ago.  The doctor wanted to prescribe a medication, but I said I wanted to fix it myself.  After much research, I identified what was needed for good bone growth.  When I looked at all the vitamins/ minerals, I found that by taking two Centrum silve for Men daily, along with Vitamin K2, that was all I needed.  about 20 months later, a re-test showed significant improvement.  I continue to take  Centrum and K2 every day.  

So what you need is to find a good thyroid doctor that will treat clinically for symptoms and for levels of both FT4 and FT3. without concern for TSH.   Those are hard to find.   Endocrinologists seem to be the most rigid about following the Guidelines.   DO's are more likely to treat clinically as described.  Also Integrative doctors or Naturopaths.

If you want to confirm what I have said, have a look at a paper I wrote, along with my two co-authors.

https://thyroiduk.org/wp-content/uploads/2023/10/A-Patients-Guide-to-the-Diagnosis-and-Treatment-of-Hypothyroidism-V5.pdf