Hello, Thank you for asking your question at health care magic Thankyou for asking your question at healthcare magic Tiredness can be due to several disorders like -Sleep Disorders -Medications -depression, stress -Autoimmune disorders -hypothyroidism -Anemia -Underlying malignancy -Central nervous system disorders There are several various causes more than listed here that can be causes for tiredness. Even though you are already on thyroid medications, it is good to check the thyroid function if it has been long time since thyroid levels have been checked. I recommend that you need to consult your doctor to get further evaluated. At this point it is difficult to give a defenite conclusion without knowing more into your history, physical and investigations. Hope I was able to answer your question Please feel free to address any more concerns Regards, Dr.Lekshmi