Name: Levothyroxine (L-Thyroxine) sodium
Brand: Selleck Chemicals
SKU: S3747
Availability: InStock
Rating: 5 (1 reviews)

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Quality Control

Batch: Purity: 99.56%

99.56

Related Targets	Dehydrogenase HSP Transferase P450 (e.g. CYP17) PDE phosphatase PPAR Vitamin Carbohydrate Metabolism Mitochondrial Metabolism
Other THR Inhibitors	MGL-3196 (Resmetirom) L-Thyroxine sodium salt pentahydrate TI17 dextrothyroxine sodium Eprotirome (KB2115) Tiratricol ALG-055009

Solubility

In vitro
Batch:

DMSO : 100 mg/mL (125.17 mM)
(Moisture-contaminated DMSO may reduce solubility. Use fresh, anhydrous DMSO.)

Water : Insoluble

Ethanol : Insoluble

Molarity Calculator

Mass	Concentration	Volume	Molecular Weight
Mass value Mass unit	Concentration value Concentration unit	Volume value Volume unit	Molecular weight (g/mol)

Dilution Calculator Molecular Weight Calculator

In vivo batch selection In vivo Batch:
Homogeneous suspension	CMC-NA	≥5mg/ml	Taking the 1 mL working solution as an example, add 5 mg of this product to 1 ml of CMC-Na solution, mix evenly to obtain a homogeneous suspension with a final concentration of 5 mg/ml.
Homogeneous suspension	CMC-NA	≥5mg/ml	Taking the 1 mL working solution as an example, add 5 mg of this product to 1 ml of CMC-Na solution, mix evenly to obtain a homogeneous suspension with a final concentration of 5 mg/ml.
Homogeneous suspension	CMC-NA	≥5mg/ml	Taking the 1 mL working solution as an example, add 5 mg of this product to 1 ml of CMC-Na solution, mix evenly to obtain a homogeneous suspension with a final concentration of 5 mg/ml.
Clear solution	5%DMSO 1 40%PEG300 2 5%Tween80 3 50%ddH2O Validated by Selleck labs. Should you need adjustments to this formulation, contact our sales team for custom testing.	5mg/ml (6.26mM)	Taking the 1 mL working solution as an example, add 50 μL of 100 mg/ml clarified DMSO stock solution to 400 μL of PEG300, mix evenly to clarify it; add 50 μL of Tween80 to the above system, mix evenly to clarify; then continue to add 500 μL of ddH2O to adjust the volume to 1 mL. The mixed solution should be used immediately for optimal results.
Clear solution	5% DMSO 1 95% Corn oil Validated by Selleck labs. Should you need adjustments to this formulation, contact our sales team for custom testing.	5mg/ml (6.26mM)	Taking the 1 mL working solution as an example, add 50 μL of 100 mg/ml clear DMSO stock solution to 950 μL of corn oil and mix evenly. The mixed solution should be used immediately for optimal results.

In vivo Formulation Calculator (Clear solution)

Step 1: Enter information below (Recommended: An additional animal making an allowance for loss during the experiment)

Dosage: mg/kg

Average weight of animals: g

Dosing volume per animal: μL

Number of animals:

Step 2: Enter the in vivo formulation (This is only the calculator, not formulation. Please contact us first if there is no in vivo formulation at the solubility Section.)

% DMSO

%

% Tween 80

% ddH₂O

% DMSO

+

%

Calculation results:

Working concentration: mg/ml;

Method for preparing DMSO master liquid: mg drug pre-dissolved in μL DMSO ( Master liquid concentration mg/mL, Please contact us first if the concentration exceeds the DMSO solubility of the batch of drug. )

Method for preparing in vivo formulation: Take μL DMSO master liquid, next addμL PEG300, mix and clarify, next addμL Tween 80, mix and clarify, next add μL ddH₂O, mix and clarify.

Method for preparing in vivo formulation: Take μL DMSO master liquid, next add μL Corn oil, mix and clarify.

Note: 1. Please make sure the liquid is clear before adding the next solvent.
2. Be sure to add the solvent(s) in order. You must ensure that the solution obtained, in the previous addition, is a clear solution before proceeding to add the next solvent. Physical methods such
as vortex, ultrasound or hot water bath can be used to aid dissolving.

Chemical Information, Storage & Stability

Molecular Weight	798.85	Formula	C₁₅H₁₀I₄NO₄.Na	Storage (From the date of receipt)	3 years-20°Cpowder
CAS No.	55-03-8	Download SDF		Storage of Stock Solutions	1 year-80°Cin solvent 1 month-20°Cin solvent

Read more about storage stability stock solution CAS number

Mechanism of Action

In vitro	Levothyroxine can upregulate the expression of P-gp mRNA and protein in LS180 cells and can produce the same effect in Caco-2 cells, which are relatively lacking in PXR. It doea not affect the expression of CYP3A4 in either cell line.
In vivo	Levothyroxine is a synthetic T4 hormone that is biochemically and physiologically indistinguishable from the natural one, and it is administered when the body is deficient in the natural hormone. Its nain site of absorption is small intestine, more specifically through the duodenum, jejunum and ileum. Very little is absorbed in the stomach. The bioavailability is about 70-80 % in euthyroid person and may be slightly higher in hyperthyroid patients. The absorption of levothyroxine appears to be influenced by gastric pH. Tmax=2-3 hours and the half-time T_1/2 is 6.2 and 7.5 days in euthyroid and hypothyroid patients, respectively. T4 hormones is known to modulate the expression of ionic channels, pumps and regulatory contractile proteins. T4-treatment induces a dose-dependent increase in the duration of contractions. Abnormal uterine contractile pattern are induced by T4-treatment.
References	[1] https://pubmed.ncbi.nlm.nih.gov/15258100/ [2] http://www.sciencedirect.com/science/article/pii/S2214623714000374 [3] http://www.touchendocrinology.com/articles/review-pharmacokinetics-levothyroxine-treatment-hypothyroidism/page/3/0

Clinical Trial Information

(data from https://clinicaltrials.gov, updated on 2025-09-23)

NCT Number	Recruitment	Conditions	Sponsor/Collaborators	Start Date	Phases
NCT06652113	RECRUITING	Recurrent Pregnancy Loss; Euthyroid With Thyroid Antibodies	Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University	2024-11-15
NCT07380854	RECRUITING	Subclinical Hypothyroidism	Seoul National University Bundang Hospital	2022-02-27
NCT07787585	NOT_YET_RECRUITING	Hypothyroidism	Spyridoula Maraka	2027-10	PHASE4
NCT05316922	RECRUITING	Hypothyroidism; Irradiation	Fondazione IRCCS Istituto Nazionale dei Tumori, Milano	2021-12-13	PHASE3
NCT07421869	RECRUITING	Hypothyroidism	Seoul National University Bundang Hospital	2024-06-12
NCT07568574	ENROLLING_BY_INVITATION	Safety and Impact of Medically Supervised Performance Enhancing Substance Usage in Healthy Elite Athletes	Enhanced Emirates Limited	2026-03-12

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Levothyroxine (L-Thyroxine) sodium THR agonist

Chemical Structure

Molecular Weight: 798.85