Hello and welcome to HCM
Low T4 is due to hypothyroidism
Irregular menstrual cycles occur in hypothyoidism. Hormone replacement is required with eltroxin
or any other thyroid hormone replacement
However, your symptoms are not getting relieved even after starting eltroxin and the levels of T4 are still low.
In this case I advice you to get your all thyroid hormones done- TSH
, T3 and T4.
If the levels of thyroid hormones are still low, the dosage of the medicine needs to be increased.
Stopping the medicine is not the solution to the problem.
Thanks and take care
Dr Shailja P Wahal