Drug

Thyroxine

In clinical development

Emerging researchLate-stage developmentSteady momentum

Also known as Eltroxin, Ermeza, Euthyrox, L-T4+26 more

Eltroxin, Ermeza, Euthyrox, L-T4, L-Thyroxine, LEVOTHYROXINE, LT4, Levo-T, Levotabs, Levothroid, Levothyroxin, Levoxyl, Synthroid, T4, T4 - thyroxine, Thyquidity, Thyro-Tabs, ThyroKare, Thyrocryn, Thyrolar, Thyrox, Tirosint, Unithroid, 3,3',5,5'-Tetraiodo-L-thyronine, 3,5,3',5'-Tetraiodo-L-thyronine, 3,5,3'5' tetraiodothyronine, 4-(4-Hydroxy-3,5-diiodophenoxy)-3,5-diiodo-L-phenylalanine, Levothyroxine Sodium, O-(4-Hydroxy-3,5-diidophenyl)-3,5-diiodo-L-tyrosine, O-(4-Hydroxy-3,5-diiodophenyl)-3,5-diiodo-L-tyrosine.

RxNorm10582 ChEMBLCHEMBL1624UNIIQ51BO43MG4

Research papers

Active clinical trials

Latest activity

beta

Recent clinical, regulatory, research and industry developments relating to this drug.

A Prospective, Single-arm Phase II Study of Thyroxine Replacement Therapy After Lobectomy for Low-risk Papillary Thyroid Carcinoma

Clinical trial2026-07-31Primary completion · ClinicalTrials.gov

Letrozole Alone vs. Letrozole Plus Levothyroxine for Ovulation Induction in Infertile Women With Both (Polycystic Ovary Syndrome) PCOS and Sub-clinical Hypothyroidism.

Clinical trial2026-05-30Primary completion · ClinicalTrials.gov

Impact of Medically Supervised Performance-Enhancing Substances (PES) on Elite Athletes: A Hybrid Design in a Real-World Setting

Clinical trial2026-05-06Results expected Q2 2028 · ClinicalTrials.gov

The Effect of Levothyroxine Treatment on Cardiac Function in Children With Subclinical Hypothyroidism

Clinical trial2026-05-01Primary completion · ClinicalTrials.gov

Novel Approaches to the Treatment of Hypothyroidism

Clinical trial2026-03-19Results expected Q4 2027 · ClinicalTrials.gov

COmparison of Two Alternative Thyrotropin Suppression Strategies Among Patients With Advanced Differentiated Cancer of the tHyroid

Clinical trial2026-02-06Results expected Q4 2027 · ClinicalTrials.gov

A Phase II Trial In Which Patients With Metastatic Alveolar Soft Part Sarcoma Are Randomized to Either Sunitinib or Cediranib Monotherapy, With Cross-Over at Disease Progression

Clinical trial2026-02-02Results posted · ClinicalTrials.gov

Thyroid Hormone Replacement After Coronary Artery Bypass Grafting for Patients With Subclinical Hypothyroidism

Clinical trial2026-02-02Results expected Q1 2032 · ClinicalTrials.gov

Impaired sensitivity to thyroid hormones is positively associated to metabolic syndrome severity in euthyroid Chinese adults as revealed by a cross-sectional study.

Research2025-05-15Frontiers in endocrinology

Thyroid Hormone Homeostasis in Levothyroxine-treated Patients: Findings From ELSA-Brasil.

Research2024-09-01The Journal of clinical endocrinology and metabolism

Hypothyroidism and metabolic cardiovascular disease.

Research2024-06-03Frontiers in endocrinology

Multi-trait analysis characterizes the genetics of thyroid function and identifies causal associations with clinical implications.

Research2024-01-30Nature communications

Profile

Identifiers & mechanism

Canonical identifiers, marketed brand names and mechanism, resolved across RxNorm, ChEMBL and ATC.

Canonical name

Thyroxine

Aliases & brands

EltroxinErmezaEuthyroxL-T4L-ThyroxineLEVOTHYROXINELT4Levo-TLevotabsLevothroidLevothyroxinLevoxylSynthroidT4T4 - thyroxineThyquidityThyro-TabsThyroKareThyrocrynThyrolarThyroxTirosintUnithroid3,3',5,5'-Tetraiodo-L-thyronine3,5,3',5'-Tetraiodo-L-thyronine3,5,3'5' tetraiodothyronine4-(4-Hydroxy-3,5-diiodophenoxy)-3,5-diiodo-L-phenylalanineLevothyroxine SodiumO-(4-Hydroxy-3,5-diidophenyl)-3,5-diiodo-L-tyrosineO-(4-Hydroxy-3,5-diiodophenyl)-3,5-diiodo-L-tyrosine

RxNorm CUI

10582

ChEMBL ID

CHEMBL1624

UNII

Q51BO43MG4

Clinical trials

95 trials

The current development programme across all trial phases — status mix, phase distribution and the late-stage studies shaping the evidence base.

Development programme

CLINICALTRIALS.GOV · LIVE REGISTRY

registered trials across all phases

LATEST COMPLETION 2026

Active studies

Recruiting

Late-stage (III+)

Completed

Discontinued

PHASE DISTRIBUTIONn = 95

Early Phase 11Phase 19Phase 1 / 22Phase 210Phase 2 / 37Phase 313Phase 428Phase N / A25

Late-stage studies

Phase III+ trials still open or recently active — where late-stage evidence is being generated.

Effects of Long-term L-thyroxine Replacement on Serum Lipid and Atherosclerosis in Patients With Hypothyroidism

Unknown statusPH IVShandong Provincial Hospitaln=7002023

Discontinuation of Levothyroxine Therapy for Patients With Subclinical Hypothyroidism: a Pilot Randomized, Double-blinded, Placebo-controlled Study

CompletedPH IVVA Office of Research and Developmentn=522022

Type 2 Deiodinase Gene Polymorphism and the Treatment of Hypothyroidism Caused

Unknown statusPH IVZhongshan Hospital Xiamen Universityn=502022

The Beneficial Effect of L-Thyroxine Long -Term Replacement on Lipid Profiles and Atherosclerosis in Subclinical Hypothyroidism: A Prospective Study

Unknown statusPH IVShandong Provincial Hospitaln=4002022

Comparison of Levothyroxine Formulation in Hypothyroid Patients With Enteral Feeding

TerminatedPH IVUniversity of California, Los Angelesn=32022

Recent completions

Trials that read out recently, adding to the completed evidence base.

A Phase II Trial In Which Patients With Metastatic Alveolar Soft Part Sarcoma Are Randomized to Either Sunitinib or Cediranib Monotherapy, With Cross-Over at Disease Progression

CompletedPH IINational Cancer Institute (NCI)n=342026

A Randomized, Double-blind, Dose-Conversion Study to Evaluate the Safety and Efficacy of Hormone Replacement Therapy With North Star Compared to Levothyroxine in Subjects With Primary Hypothyroidism Who Are Euthyroid on Levothyroxine Replacement Therapy

CompletedPH IINeuvosyn Laboratories, LLCn=3032025

Role of Levothyroxine Supplementation in Delayed Recovery Following Cardiac Surgery

CompletedPH IIIAin Shams Universityn=702025

To Compare the Effectiveness of Vitamin D & Levothyroxine Combination Therapy and Levothyroxine Alone on Serum Lipid Profile in Patients With Hypothyroidism

CompletedPH IIIKing Edward Medical Universityn=622025

A Clinical Study to Evaluate the Effect of MK-0616 on the Pharmacokinetics of Levothyroxine in Healthy Adult Participants

CompletedPH IMerck Sharp & Dohme LLCn=282024

The Role of Immunomodulatory Treatment in Success of ICSI in Patients Who Have Infertility With Autoimmune Thyroiditis

CompletedPH IIAljazeera Hospitaln=1942024

Research activity

12 papers

Key research shaping understanding of this drug, combining the latest publications with the most influential evidence.

Publications over time

20102025

Most influential

Molecular aspects of thyroid hormone actions.

Endocrine reviews · 2010 · 910 cites

Association of Thyroid Function Test Abnormalities and Thyroid Autoimmunity With Preterm Birth: A Systematic Review and Meta-analysis.

JAMA · 2019 · 233 cites

Thyroid hormone early adjustment in pregnancy (the THERAPY) trial.

The Journal of clinical endocrinology and metabolism · 2010 · 102 cites

Multi-trait analysis characterizes the genetics of thyroid function and identifies causal associations with clinical implications.

Nature communications · 2024 · 62 cites

Thyroid Stimulating Hormone and Thyroid Hormones (Triiodothyronine and Thyroxine): An American Thyroid Association-Commissioned Review of Current Clinical and Laboratory Status.

Thyroid : official journal of the American Thyroid Association · 2023 · 43 cites

Autoantibodies to selenoprotein P in chronic fatigue syndrome suggest selenium transport impairment and acquired resistance to thyroid hormone.

Redox biology · 2023 · 21 cites

Related diseases

1 conditions

Regulator-approved indications and conditions co-mentioned with this drug across the research literature. Number shows shared papers.

Active research areas

Hypothyroidism5

Related drugs

3 matches

Drugs sharing diseases, protein targets and literature with this one. Ranked by graph evidence (shared targets + diseases weighted above co-mentions).

Thyrotropin

Studied across 9 of the same disease areas as Thyroxine in the shared literature.

9 shared diseases7 shared papers

Vitamin D

Studied across 7 of the same disease areas as Thyroxine in the shared literature.

7 shared diseases1 shared paper

Triiodothyronine

Studied across 2 of the same disease areas as Thyroxine in the shared literature.

2 shared diseases4 shared papers

References & data sources

RxNorm (U.S. National Library of Medicine) — drug identity
ChEMBL (EMBL-EBI) & UniProt — pharmacology and targets
Europe PMC — research literature
ClinicalTrials.gov — clinical trials