Hi Gr8Nica and welcome to the forum.
The aim of a treated hypo patient generally is for TSH to be 1 or below or wherever it is needed for FT4 and FT3 to be in the upper part of their reference ranges, if that is where you feel well, when on Levo only.
Dr Toft, leading endocrinilogist and past president of the British Thyroid Association, states in Pulse Magazine, "The appropriate dose of levothyroxine is that which restores euthyroidism and serum TSH to the lower part of the reference range - 0.2-0.5mU/l.
In this case, free thyroxine is likely to be in the upper part of its reference range or even slightly elevated – 18-22pmol/l. Most patients will feel well in that circumstance.
But some need a higher dose of levothyroxine to suppress serum TSH and then the serum-free T4 concentration will be elevated at around 24-28pmol/l.
This 'exogenous subclinical hyperthyroidism' is not dangerous as long as serum T3 is unequivocally normal – that is, serum total around T3 1.7nmol/l (reference range 1.0-2.2nmol/l)."
To know if you are converting T4 to T3 well enough, then the free Ts should be in balance. If FT4 is high in range/over range and FT3 low in it's range, that is indicative of poor conversion. Another way to know is the FT4:FT3 ratio. Good conversion takes place when, upon being adequately treated with Levo (ie low TSH), the ratio is 4:1 or less. To find the ratio divide FT4 by FT3 eg
FT4 - 20 (12-22)
FT3 - 4 (3.1-6.8)
20 divided by 4 = 5:1 = poor conversion
For Vitamins and Minerals, the following levels are recommended for thyroid hormone to work properly
Vit D - 100-150nmol/L (the recommended level according to the Vit D Council)
B12 - An extract from the book, "Could it be B12?" by Sally M. Pacholok:
"We believe that the 'normal' serum B12 threshold needs to be raised from 200 pg/ml to at least 450 pg/ml because deficiencies begin to appear in the cerebrospinal fluid below 550".
"For brain and nervous system health and prevention of disease in older adults, serum B12 levels should be maintained near or above 1000 pg/ml."
Folate - at least half way through it's range
Ferritin - half way through it's range, with a minimum of 70 for thyroid hormone to work.
Bear in mind, this information is from patients who share their experiences and may not be the opinion of doctors unless backed by evidence from a reliable, reputable and acceptable source.
If you have any results, please post them with their reference ranges, for comment.