T4/T3 Therapy in Hypothyroidism

Starting soon · Phase 2 · Has a placebo group

Conditions studied: Hypothyroidism Primary

In brief

This study will test whether 6 months of combination therapy with levothyroxine (LT4) plus liothyronine (LT3) is superior to LT4 plus placebo in participants with hypothyroidism who have residual symptoms of hypothyroidism with TSH levels within the reference range.

Key facts

Study ID

NCT07424183

Run by

University of Pennsylvania

People needed

60

Starts

2026-06-01

Expected to finish

2027-06-01

Last updated by the study team

2026-04-21

Who can join

Age: 18 and older, up to 70. Sex: any. Healthy volunteers: not accepted.

You may qualify if…

• Male or female, aged 18-70 years
• Hypothyroidism due to either thyroid failure or total thyroidectomy for structural thyroid disease (nodules, benign goiter, or thyroid cancer) for at least 6 months
• Taking 75-150 mcg per day LT4 and a minimum of 1.2 mcg/kg/day, with stable dose of LT4 for at least 3 months prior to enrollment
• TSH of 0.5 to 4.0 mU/L within 2 months of enrollment
• Persistent symptoms for at least 2 months, and a TSQ score of ≥ 5
• For females of reproductive potential: use of highly effective contraception for at least 1 month prior to screening and agreement to use such a method during study participation and for an additional 4 weeks after the end of study intervention.

You may not qualify if…

• Current use of LT3, thyroid extracts, Tirosint liquid or capsules, amiodarone, lithium, methimazole, propylthiouracil, supraphysiologic doses of corticosteroids, immunotherapy, tyrosine kinase inhibitors, interferon, or biotin supplements
• Diseases of the pituitary or hypothalamus
• History of thyroid cancer requiring suppression of TSH secretion
• Unstable cardiac conditions, including uncontrolled hypertension (current blood pressure greater than 160/100), arrhythmia, or angina
• Uncontrolled psychiatric disorders
• Pregnancy or lactation, or planned pregnancy within the next 7 months
• History of food dye allergies
• GFR <30 ml/min/1.73 m2
• Other conditions which, in the opinion of the investigators, would prevent them from participating in the full duration of the study (for example, end-stage cancer)

Where it is running

• Penn Medicine, Smilow Center for Translational Resarch, — Philadelphia, Pennsylvania, United States

Full record on ClinicalTrials.gov

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