Energy Metabolism in Thyroidectomized Patients

In this study, Levothyroxine (LT4) and placebo (a look-alike inactive substance, a "sugar pill") will be compared to Liothyronine/ Levothyroxine (LT3/LT4) combination therapy. Levothyroxine LT4 and Liothyronine (LT3) are drugs approved by the U. S. Food and Drug Administration (FDA). All participants will be required follow VCU Health COVID-19 standard of Care screening procedures. This study requires approximately five study visits The five-study visits required will be a Screening Visit (outpatient), one Baseline Visit, (inpatient) one Six Week Visit, (outpatient), one Three Month Visit and one Six Month Visit (both inpatient). A COVID-19 test will be done 48 hours (2 days) before each of the three-inpatient visit, Baseline Visit, Three Month and Six Month Visit. Participants will be asked to: 1. Give permission for the researchers to collect information about their medical history from participants and their medical records five times during the study visits and for 5 years after the study visits. 2. Have a Physical exam done 5 times 3. 24-hour energy expenditure recording in the Whole room indirect calorimeter studies 3 times (inpatient overnight stays: Baseline, Three months, and Six months visits) 4. Study drug will be dispensed three times 5. Have study drug dose adjustments two times 6. Genomic blood draw for DNA one time 7. Have blood drawn five times 8. Have an DXA Scan two times 9. Have an Echocardiogram three times 10. Complete questionnaire three times 11. Have Accelerometers sensors laced 3 times (inpatient overnight stays: Baseline, Three months, and Six months visits) 12. ClearSight (blood pressure monitoring) procedure three times 13. Be randomized to take either Levothyroxine LT4 + placebo group or LevothyroxineLT3/Liothyronine LT4 group from baseline through 6 months Participation in this study will last up to 6 months after surgery. Approximately 30 total individuals will participate in this study