Timing of Thyroxine Dose In Ramadan

Inclusion Criteria: * Saudi patient (males and female) above 18 years with Primary hypothyroidism on levothyroxine replacement who are willing to fast during Ramadan. * Patients with controlled thyroid function for last 3 months on same dose of levothyroxine. Exclusion Criteria: * Pregnant or lactating women. * Uncontrolled thyroid function test three months prior Ramadan. * Thyroid cancer patients who require suppressed TSH. * Central Hypothyroidism, patient with acute illness. * Patients diagnosed with malabsorption i.e., Celiac Disease, Short bowel, Bariatric surgeries * Use of certain Medications like systemic glucocorticoids, activated charcoal, sucralfate, aluminum hydroxide antacid, bile acid sequestrants, iron, calcium carbonate, PPI, rifampicin, and antiepileptic medications * Renal or hepatic disease: * Creatinine clearance \<0.6 ml/s or serum creatinine ≥200 μmol/l * Alanine transferase ≥2.5 times the upper limit of normal * Active liver disease including jaundice, chronic hepatitis, previous liver transplant * Unwillingness to be randomized or to sign informed consent * Known Psychiatric Disorders * Known uncontrolled substance abuse or alcoholism