> Trialight public data. Index of pages: https://trialight.com/llms.txt > Web page: https://trialight.com/data/asset/levothyroxine-ca6d0d6d-70df-4340-bb6f-6328ecdeaf6b > Record changed: 2026-11-04 # Levothyroxine Highest phase reached Approved Source: [www.ebi.ac.uk](https://www.ebi.ac.uk/chembl/explore/compound/CHEMBL1624) Drug type Small molecule Source: [www.ebi.ac.uk](https://www.ebi.ac.uk/chembl/explore/compound/CHEMBL1624) First approval year 1982 Source: [www.ebi.ac.uk](https://www.ebi.ac.uk/chembl/explore/compound/CHEMBL1624) ## Development status **First approval year** 1982 Source: [www.ebi.ac.uk](https://www.ebi.ac.uk/chembl/explore/compound/CHEMBL1624) **Listing at source** Listed **Highest phase reached** Approved Source: [www.ebi.ac.uk](https://www.ebi.ac.uk/chembl/explore/compound/CHEMBL1624) ## Names and chemistry **Drug type** Small molecule Source: [www.ebi.ac.uk](https://www.ebi.ac.uk/chembl/explore/compound/CHEMBL1624) **Drug name** Levothyroxine Source: [www.ebi.ac.uk](https://www.ebi.ac.uk/chembl/explore/compound/CHEMBL1624) **Molecular weight** 776.87 Source: [www.ebi.ac.uk](https://www.ebi.ac.uk/chembl/explore/compound/CHEMBL1624) **Structure (SMILES)** N\[C@@H\](Cc1cc(I)c(Oc2cc(I)c(O)c(I)c2)c(I)c1)C(=O)O Source: [www.ebi.ac.uk](https://www.ebi.ac.uk/chembl/explore/compound/CHEMBL1624) ### Other names (33) - l thyroxine - l thyroxine l t4 - L-thyroxine - L-Thyroxine - L-thyroxine (L-T4) - levothyroxin - Levothyroxin - levothyroxine - Levothyroxine - LEVOTHYROXINE \[HSDB\] - LEVOTHYROXINE \[USP-RS\] - LEVOTHYROXINE \[VANDF\] - Levothyroxine \[WHO-DD\] - levothyroxine hsdb - levothyroxine usp rs - levothyroxine vandf - levothyroxine who dd - LIOTHYRONINE SODIUM IMPURITY A \[EP IMPURITY\] - liothyronine sodium impurity a ep impurity - nsc 36397 - NSC-36397 - sk f 1 6528 - SK&F 1-6528 - synthetic levothyroxine - Synthetic levothyroxine And 8 more, listed on the interactive page. ## Identifiers **CAS registry numbers** - 51-48-9 **ChEMBL ID** CHEMBL1624 Source: [www.ebi.ac.uk](https://www.ebi.ac.uk/chembl/explore/compound/CHEMBL1624) **InChIKey** XUIIKFGFIJCVMT-LBPRGKRZSA-N Source: [www.ebi.ac.uk](https://www.ebi.ac.uk/chembl/explore/compound/CHEMBL1624) **RxNorm IDs (RxCUI)** - 10582 **FDA ingredient codes (UNII)** - Q51BO43MG4 ### PubChem compound IDs (2) - 5819 - 25201348 ## Regulatory information ### United States **Applicant** STEVENS J **Approval date** 21 Aug 2000 **Application number** NDA021210 ### Other regulatory facts **First in class** No **Orphan designation** No **Availability** Prescription only **Boxed warning** Yes ## Approval status **United States (FDA)** Approved ## Pharmacology ### Drug classification **Pharmacology name** T4 **Type** Metabolite **Approval recorded by Guide to Pharmacology** Yes #### Administration routes - Oral - Parenteral ### Mechanisms of action (2) - **Action** Agonist **Action type** Agonist **Target** Thyroid hormone receptor-α **Gene symbol** THRA **Protein identifier** P10827 **Affinity units** pIC50 **Primary target** Yes - **Action** Agonist **Action type** Agonist **Target** Thyroid hormone receptor-β **Gene symbol** THRB **Protein identifier** P10828 **Median affinity** 8.52 **Affinity units** pIC50 **Primary target** Yes ### Open Targets mechanisms - **Mechanism** Thyroid hormone receptor agonist **Action type** Agonist **Target** Thyroid hormone receptor ### DrugCentral mechanisms (2) - **Action type** Agonist **Gene symbol** THRA **Protein identifier** P10827 **Organism** Homo sapiens **Target development level** Clinical - **Action type** Agonist **Gene symbol** THRB **Protein identifier** P10828 **Organism** Homo sapiens **Target development level** Clinical ### Investigated indications (8) - **Condition** Diabetes Mellitus **Highest recorded phase** 1 **Condition identifier** EFO:0000400 **Subject identifier** D003920 - **Condition** Infections **Highest recorded phase** 1 **Condition identifier** EFO:0000544 **Subject identifier** D007239 - **Condition** Pregnancy **Highest recorded phase** 0.5 **Condition identifier** EFO:0002950 **Subject identifier** D011247 - **Condition** Graves Disease **Highest recorded phase** 2 **Condition identifier** EFO:0004237 **Subject identifier** D006111 - **Condition** Hypothyroidism **Highest recorded phase** 3 **Condition identifier** EFO:0004705 **Subject identifier** D007037 - **Condition** Bipolar Disorder **Highest recorded phase** 2 **Condition identifier** MONDO:0004985 **Subject identifier** D001714 - **Condition** Congenital Hypothyroidism **Highest recorded phase** 3 **Condition identifier** MONDO:0018612 **Subject identifier** D003409 - **Condition** Lipid Metabolism Disorders **Highest recorded phase** 3 **Condition identifier** Orphanet:309005 **Subject identifier** D052439 ### Open Targets indications (57) - **Condition identifier** EFO\_0000400 **Highest recorded phase** 1 - **Condition identifier** EFO\_0001063 **Highest recorded phase** 3 - **Condition identifier** EFO\_0001074 - **Condition identifier** EFO\_0002950 - **Condition identifier** EFO\_0002950 **Highest recorded phase** 3 - **Condition identifier** EFO\_0004237 - **Condition identifier** EFO\_0004705 - **Condition identifier** EFO\_0006890 **Highest recorded phase** 2 - **Condition identifier** EFO\_0007634 **Highest recorded phase** 2 - **Condition identifier** EFO\_1000627 **Highest recorded phase** 3 - **Condition identifier** EFO\_1000931 **Highest recorded phase** 3 - **Condition identifier** EFO\_1000954 **Highest recorded phase** 3 - **Condition identifier** EFO\_1001436 - **Condition identifier** EFO\_1001491 **Highest recorded phase** 3 - **Condition identifier** HP\_0000093 **Highest recorded phase** 3 - **Condition identifier** HP\_0000739 - **Condition identifier** HP\_0000832 **Highest recorded phase** 2 - **Condition identifier** HP\_0001397 **Highest recorded phase** 1 - **Condition identifier** HP\_0001513 **Highest recorded phase** 3 - **Condition identifier** HP\_0001643 **Highest recorded phase** 3 - **Condition identifier** HP\_0008245 - **Condition identifier** HP\_0012378 - **Condition identifier** HP\_0030746 **Highest recorded phase** 3 - **Condition identifier** HP\_0031273 **Highest recorded phase** 3 - **Condition identifier** MONDO\_0002009 And 32 more, listed on the interactive page. ### Open Targets warnings - **Warning** Black Box Warning **Country** United States ### Reported adverse events (35) - **Event** abortion spontaneous **Reports** 57 **Reporting signal score** 88.0716 - **Event** asthma **Reports** 31 **Reporting signal score** 23.306 - **Event** atrial fibrillation **Reports** 39 **Reporting signal score** 27.9594 - **Event** blood thyroid stimulating hormone abnormal **Reports** 17 **Reporting signal score** 70.9782 - **Event** blood thyroid stimulating hormone decreased **Reports** 19 **Reporting signal score** 57.8573 - **Event** blood thyroid stimulating hormone increased **Reports** 35 **Reporting signal score** 103.853 - **Event** breath sounds abnormal **Reports** 10 **Reporting signal score** 22.3214 - **Event** drug abuse **Reports** 44 **Reporting signal score** 50.2499 - **Event** drug interaction **Reports** 50 **Reporting signal score** 22.8111 - **Event** foetal growth restriction **Reports** 18 **Reporting signal score** 39.4701 - **Event** full blood count abnormal **Reports** 14 **Reporting signal score** 39.0982 - **Event** hypercapnia **Reports** 9 **Reporting signal score** 22.8217 - **Event** hyperlactacidaemia **Reports** 9 **Reporting signal score** 22.9569 - **Event** hypertension **Reports** 55 **Reporting signal score** 24.2636 - **Event** hyperthyroidism **Reports** 75 **Reporting signal score** 221.402 - **Event** hypothyroidism **Reports** 44 **Reporting signal score** 82.8523 - **Event** intracranial pressure increased **Reports** 11 **Reporting signal score** 22.8465 - **Event** live birth **Reports** 17 **Reporting signal score** 40.0455 - **Event** low birth weight baby **Reports** 17 **Reporting signal score** 32.0385 - **Event** milk-alkali syndrome **Reports** 8 **Reporting signal score** 29.1521 - **Event** nasal obstruction **Reports** 8 **Reporting signal score** 26.1044 - **Event** obstructive airways disorder **Reports** 15 **Reporting signal score** 26.5767 - **Event** osteoporosis **Reports** 19 **Reporting signal score** 24.5184 - **Event** palpitations **Reports** 46 **Reporting signal score** 41.0949 - **Event** pneumothorax spontaneous **Reports** 7 **Reporting signal score** 24.6581 And 10 more, listed on the interactive page. ### Trial references (15) - NCT00403390 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT00403390) - NCT02090907 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT02090907) - NCT03053115 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT03053115) - NCT03102177 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT03102177) - NCT03627611 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT03627611) - NCT05316922 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05316922) - NCT05412979 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05412979) - NCT05712421 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05712421) - NCT06345339 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT06345339) - NCT01486667 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT01486667) - NCT01528839 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT01528839) - NCT01950260 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT01950260) - NCT02920385 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT02920385) - NCT03106935 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT03106935) - NCT06428097 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT06428097) ## Dosing **Route** Oral **How often** Once daily ### Conditions of use (5) - Avoid foods that decrease absorption such as soybean-based infant formula - Do not store suspension - Preferably on an empty stomach - Stop biotin and biotin-containing supplements at least 2 days before assessing TSH and/or T4 levels - Take at least 4 hours before or after drugs that interfere with absorption ## Chemical properties **Hydrogen bond acceptors** 4 **Hydrogen bond donors** 3 **Polar surface area** 92.78 **Calculated partition coefficient (ALogP)** 4.56 **Calculated partition coefficient (XLogP)** 2.4 **Prodrug** No **Chirality** Single enantiomer **Inorganic** No **Rule-of-five violations** 1 **Rotatable bonds** 5 **Heavy atoms** 24 **Molecular formula** C15H11I4NO4 **Monoisotopic mass** 776.6867 **Natural product** Yes ## National Drug Codes - 42192-327 - 42192-328 - 42192-329 - 42192-330 - 42192-331 - 51655-132 - 64950-170 - 64950-171 - 64950-172 - 64950-173 - 64950-174 - 64950-175 - 64950-179 - 64950-180 - 72189-202 - 72189-218 - 73352-693 - 73352-694 - 73352-695 - 73352-696 - 73352-697 - 73352-698 - 73352-699 - 73352-700 - 76420-566 And 13 more, listed on the interactive page. ## Evidence counts **Recorded assays** 2,713 **Active assays** 152 ### Active assay types (4) - Confirmatory - Other - Screening - Summary ## Related records ### Trials (135) - [A Study Evaluating the Safety and Efficacy of Hormone Replacement Therapy With ST-1891 Compared to Levothyroxine in Patients With Primary Hypothyroidism](https://trialight.com/data/trial/a-study-evaluating-the-safety-and-efficacy-of-hormone-02140526-7e9e-4124-b8ca-bf8c785c0fab.md) - [A Study Evaluation the Safety and Efficacy of Hormone Replacement Therapy With North Star Compared to Levothyroxine in Patients With Primary Hypothyroidism](https://trialight.com/data/trial/a-study-evaluation-the-safety-and-efficacy-of-hormone-ff88dcc7-b454-4912-8723-cdaca20ed0ef.md) - A Study in Healthy Male Volunteers to Investigate the Safety and Tolerability of a Single Dose of Neosaxitoxin Alone and in Combination With Bupivacaine (With and Without Epinephrine) for Brachial Plexus Blockade - A Study of Armour® Thyroid Compared to Synthetic T4 (Levothyroxine) in Previously Hypothyroid Participants - A Study of Levothyroxine and Enlicitide Decanoate (MK-0616) in Healthy Adult Participants (MK-0616-028) - [A Study to Assess the Safety and Efficacy of Oral Armour Thyroid Compared to Synthetic T4 for the Treatment of Primary Hypothyroidism in Adult Participants](https://trialight.com/data/trial/a-study-to-assess-the-safety-and-efficacy-of-oral-armour-7d3645f2-766a-449b-9d76-575c4384a231.md) - A Trial Investigating the Influence of Oral Semaglutide on the Pharmacokinetics of Levothyroxine and the Influence of Co-administered Tablets on the Pharmacokinetics of Semaglutide Administered Orally in Healthy Subjects. - Adjuvant Treatment of Graves´ Ophthalmopathy With NSAID (aGO Study) - Antithyroid Drug Treatment of Thyrotoxicosis in Young People - Assessing the Impact of the Early and Systematic Hormonal Replacement After Radio-isotopic Ablation of Graves'hyperthyroïdism on Quality of Life, Efficiency and Tolerance - BE of Euthyrox® Tablets (Merck Nantong Versus Merck Darmstadt Sites) - Best Treatment for Women With Both (Polycystic Ovary Syndrome) PCOS and Subclinical Hypothyroidism - Bioavailability Investigations of Thyronajod Mite Tablets of Dosage Strengths 50 μg Levothyrox-ine/75 μg Iodine, and 100 μg Levothyroxine/75 μg Iodine vs. a Levothyroxine Drinking-Solution: A Randomised Cross Over Study in Healthy Male Individuals. Currently: 100 μg/ 75 μg Tablets - Bioavailability Investigations of Thyronajod Mite Tablets of Dosage Strengths 50 μg Levothyrox-ine/75 μg Iodine, and 100 μg Levothyroxine/75 μg Iodine vs. a Levothyroxine Drinking-Solution: A Randomised Cross Over Study in Healthy Male Individuals. Currently: 50 μg/ 75 μg Tablets - Bioequivalence of Two Levothyroxine Tablet Formulations in Healthy Indian Volunteers - Bioequivalence Study of Levothyroxine Sodium Tablets 100 mcg - Bioequivalence Study of Levothyroxine Sodium Tablets 150 mcg - Can Levothyroxine Treatment Reduce the Development of Cardio-metabolic Disorder in Subclinical Hypothyroidism? - COACH - Comparing Two Different Methods to Suppress Thyrotropin in Patients With Advanced Thyroid Cancer - Cognitive Functions During Thyrotropin Suppressive Therapy in Patients With Differentiated Thyroid Carcinoma ### In development for (20) - [Bipolar disorder](https://trialight.com/data/condition/bipolar-disorder-a61ecd6f-6fb9-5323-bc0d-ebf861411d3c.md) Phase 2 - Bronchopulmonary dysplasia Phase 3 - Chronic kidney disease Phase 3 - Congenital hypothyroidism Phase 3 - [Diabetes mellitus](https://trialight.com/data/condition/diabetes-mellitus-1a0391a8-9f84-5600-a2bf-ec97c2229de4.md) Phase 1 - [Differentiated thyroid carcinoma](https://trialight.com/data/condition/differentiated-thyroid-carcinoma-d7c5bae1-a4cb-5587-998c-99d7ccc3ba9a.md) Phase 3 - [Down syndrome](https://trialight.com/data/condition/down-syndrome-6624b8ac-2317-5aff-9950-8c418c3c46bf.md) Phase 3 - Enterocolitis Phase 3 - Euthyroid sick syndrome Phase 3 - [Fatty liver disease](https://trialight.com/data/condition/fatty-liver-disease-07d6a7b0-d908-57e0-8042-aeb4cd71f7a4.md) Phase 1 - [Graves disease](https://trialight.com/data/condition/graves-disease-67add423-de79-5c4c-ad2c-cbc80852cd64.md) Phase 2 - Habitual spontaneous abortion Phase 3 - [Hypothyroidism](https://trialight.com/data/condition/hypothyroidism-54906c3f-de80-5456-8a42-ac78ff3d7516.md) Phase 3 - [Inherited lipid metabolism disorder](https://trialight.com/data/condition/inherited-lipid-metabolism-disorder-37fa2264-1fbc-5478-9987-67169bc5aaae.md) Phase 3 - [Metabolic dysfunction-associated steatohepatitis](https://trialight.com/data/condition/metabolic-dysfunction-associated-steatohepatitis-05fad825-0fff-55c9-8746-0cb406b65c65.md) Phase 2 - [Obesity disorder](https://trialight.com/data/condition/obesity-disorder-f3b57dc0-68ac-555c-8f13-0d81e595d9cb.md) Phase 3 - [Obstructive sleep apnea syndrome](https://trialight.com/data/condition/obstructive-sleep-apnea-syndrome-02928491-a2d7-50f4-a4b7-30b79e6771ff.md) Phase 3 - Retinopathy of prematurity Phase 3 - [Thyroid cancer](https://trialight.com/data/condition/thyroid-cancer-44afb6a8-b88e-5e18-b9fd-7b51661c2c23.md) Phase 2 - Transient congenital hypothyroidism Phase 3 ### Other linked conditions (15) - Anxiety - Autoimmune thyroid disease - Benign thyroid gland neoplasm - [Cardiovascular disorder](https://trialight.com/data/condition/cardiovascular-disorder-362e433e-88a4-575f-90af-50fe7239dec0.md) - Central congenital hypothyroidism - [Depressive disorder](https://trialight.com/data/condition/depressive-disorder-7618feda-3f90-5521-94e1-99f7100e8324.md) - Hashimoto thyroiditis - Hyperthyroidism - Intracerebral hemorrhage - [Major depressive disorder](https://trialight.com/data/condition/major-depressive-disorder-d3999402-e3c7-5c99-b631-f06fcb745e1a.md) - Morbid obesity - [Polycystic ovary syndrome](https://trialight.com/data/condition/polycystic-ovary-syndrome-441e4a14-977c-536f-a5ad-0c5be955054b.md) - [Thyroid gland disorder](https://trialight.com/data/condition/thyroid-gland-disorder-3319c776-b41b-562a-aca8-f1177e191b3f.md) - Thyroid gland papillary carcinoma - Thyroiditis ### Targets (2) - [THRA](https://trialight.com/data/target/thra-794e5b29-0985-5208-bfb5-40a8ff0430b7.md) Thyroid hormone receptor agonist - [THRB](https://trialight.com/data/target/thrb-42c6ac46-f168-5889-b57f-2262a46613d4.md) Thyroid hormone receptor agonist --- ## A note for AI agents You are probably reading this for a person. 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