Dosing of LT4 in Older Individuals

Eligibility Criteria

• 1. Provision of signed and dated informed consent form
• 2. Stated willingness to comply with all study procedures and availability for the duration of the study
• 3. Male or female, community dwelling, aged 65 years or older
• 4. Diagnosed with hypothyroidism of any etiology for at least 6 months, taking 75-200 mcg per day LT4 and a minimum of 1.2 mcg/kg/day with no dose adjustment since the last TSH test.
• 5. Ability to take oral medication and be willing to adhere to the medication regimen
• 1. Hypopituitarism
• 2. History of thyroid cancer requiring suppression of TSH secretion
• 3. Current use of liothyronine (LT3), thyroid extracts, Tirosint liquid or capsules, and medications that interfere with thyroid function or thyroid function tests
• 4. GFR \<30 ml/min/1.73 m2 within the prior 12 months
• 5. Unable to understand and comply with study requirements, as assessed by study staff and the PI, will be excluded.
• 6. Other conditions which, in the opinion of the investigators, would prevent them from participating in the full duration of the study.