CAS No. 55-03-8

Batch: Purity:99.52
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Levothyroxine (L-Thyroxine) sodium Chemical Structure
Chemical Structure
Check the Levothyroxine (L-Thyroxine) sodium product page for in-depth specifications, including solubility, stock solutions, MOA, and working concentrations.

Chemical Information

IUPAC Name sodium (2S)-2-amino-3-[4-(4-hydroxy-3,5-diiodophenoxy)-3,5-diiodophenyl]propanoate
CAS Number 55-03-8
Molecular Formula

C15H10I4NO4.Na
Molecular Weight (MW) 798.85
InChIKey YDTFRJLNMPSCFM-YDALLXLXSA-M

Biological Activity

Levothyroxine (L-Thyroxine) sodium is a major thyroid gland-derived hormone that acts as an agonist of thyroid hormone receptor alpha (TRα) and thyroid hormone receptor beta (TRβ). Upon binding to these nuclear receptors, levothyroxine modulates gene expression to regulate basal metabolic rate, protein synthesis, and cellular metabolism. Activation of TR-mediated signaling pathways subsequently influences energy expenditure and developmental cell growth across diverse tissues. [1]

How to Prepare Stock Solution?

Concentration Volume Mass
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Solubility

Batch:
All in vitro solubility values are batch-tested experimental data (non-literature values).
Solvent Solubility & Note
DMSO 100 mg/mL (125.17 mM)
(Moisture-contaminated DMSO may reduce solubility. Use fresh, anhydrous DMSO. The recommended stock concentration is 10 mM in DMSO.)
Ethanol 3 mg/mL
Water Insoluble
FAQ
Q: Why does a DMSO stock precipitate in media/saline?
A: It is caused by unheated aqueous media (supersaturation), local solvent shock, or incorrect mixing sequence.
How to fix it?
  • Preheat media/saline to 37°C.
  • Mix rapidly (pipette/vortex) upon addition.
  • For complex mixes, always add the aqueous phase last.
  • Re-dissolve minor precipitates with a 37°C water bath and sonication (≤30 min).

Reference

[1] Nat Rev Cancer. 2010;10(3):157-157.

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Note: Technical data last updated: Sep 1, 2026.