Novel Approaches to the Treatment of Hypothyroidism

Inclusion Criteria:

History of hypothyroidism Treatment with levothyroxine Levothyroxine dose \>1.2 mcg/kg

Exclusion Criteria:

Body weight \<50 or \>100 Kg.

Indication for TSH suppression (high risk follicular-derived thyroid cancer).

Secondary (pituitary) hypothyroidism (ICD-10 E23.0); Pregnancy; breastfeeding; uncontrolled diabetes (HbA1c \>8.5% at screening); use of oral Semaglutide (Rybelsus); Uncontrolled Hypertension (BP \> 140/90 at screening); current use of T3-containing therapies (Liothyronine, desiccated thyroid extracts).

Patients receiving lipid-lowering therapies must maintain the same dose throughout the participation in the study. Changes in lipid lowering therapy/dose will result in termination from the study.

Patients receiving anti-acid (H2 blockers, proton pump inhibitors) therapies must maintain the same dose throughout the participation in the study. Changes in anti-acid therapy/dose will result in termination from the study. Use of other medications known to interfere with the absorption of thyroid hormone, or affecting the thyroid hormone axis (Burch 2019) will be considered exclusion criteria.

Bariatric surgery, initiation of GLP-1 agonist therapy (irrespective of the indication), enrollment in structured weight loss programs will result in dismissal from the study.

Current pregnancy, pregnancy planned within the next 6 months, and lack of contraception in women of reproductive age will be exclusionary. We will verify that the participant is not pregnant through a urine pregnancy test at the time of the first study visit and at each of the follow-up visits. Any participants who become pregnant will terminate the study.