L-Thyroxine
Also known as: Levothyroxine, 3,3',5,5'-Tetraiodo-L-thyronine, Thyroxine, T4, O-(4-Hydroxy-3,5-diiodophenyl)-3,5-diiodo-L-tyrosine, (-)-Thyroxine, L-T4, 3,5,3',5'-Tetraiodothyronine, thx, THX, beta-[(3,5-Diiodo-4-hydroxyphenoxy)-3,5-diiodophenyl]alanine
L-Thyroxine (CAS 51-48-9) is a compound in the Organic Compounds category listed in the Jingsj chemical database. It has the molecular formula C15H11I4NO4 and a molecular weight of 776.870 g/mol. Key properties include a melting point of 235 °C, a boiling point of 576.3±50.0 °C at 760 mmHg, a density of 2.6±0.1 g/cm3 and a flash point of 302.3±30.1 °C. It is classified under GHS with signal word Danger and hazard statements H225 — Highly flammable liquid and vapour, H301 — Toxic if swallowed and H311 — Toxic in contact with skin. No supplier offers are currently listed; request a quote. Record last updated Aug 21, 2026.
- CAS No.
- 51-48-9
- Jingsj CID
- J-37899-4
- Molecular Formula
- C15H11I4NO4
- Molecular Weight
- 776.870 g/mol
- Category
- Organic Compounds
- Last updated
- 8/21/2026
No offers for this compound yet.
Request a quotePhysicochemical Properties
| Melting Point | 235 °C |
|---|---|
| Boiling Point | 576.3±50.0 °C at 760 mmHg |
| Density | 2.6±0.1 g/cm3 |
| Flash Point | 302.3±30.1 °C |
| Exact Mass | 776.686646 |
| PSA | 92.78000 |
| LogP | 5.93 |
| Vapor Pressure | 0.0±1.7 mmHg at 25°C |
| Refractive Index | 1.795 |
| Additional Property | insoluble |
GHS Safety & Compliance
- H225 — Highly flammable liquid and vapour
- H301 — Toxic if swallowed
- H311 — Toxic in contact with skin
- H331 — Toxic if inhaled
- H370 — Causes damage to organs
Activity & Biological Data
| Target | Human Endogenous Metabolite |
|---|---|
| Additional Information | [1]. Arici M, et al. Association between genetic polymorphism and levothyroxine bioavailability in hypothyroid patients. Endocr J. 2018 Jan 11. [2]. Corriveau S, et al. Levothyroxine treatment generates an abnormal uterine contractility patterns in an in vitro animalmodel. J Clin Transl Endocrinol. 2015 Sep 9;2(4):144-149. |
Customs & Trade Information
| HS Code | 2922509090 |
|---|---|
| Summary | 2922509090. other amino-alcohol-phenols, amino-acid-phenols and other amino-compounds with oxygen function. VAT:17.0%. Tax rebate rate:13.0%. . MFN tariff:6.5%. General tariff:30.0% |
Frequently Asked Questions
What is the CAS number of L-Thyroxine?
The CAS number of L-Thyroxine is 51-48-9.
What are the molecular formula and molecular weight of L-Thyroxine?
L-Thyroxine has molecular formula C15H11I4NO4 and molecular weight 776.870 g/mol.
Is L-Thyroxine hazardous?
L-Thyroxine has GHS signal word Danger and hazard statements H225 — Highly flammable liquid and vapour; H301 — Toxic if swallowed; H311 — Toxic in contact with skin.
What are the upstream and downstream products of L-Thyroxine?
For L-Thyroxine, Upstream Products: 3,5-Diiodo-L-thyronine, DL-Thyroxine, N-Acetyl-3,5-diiodo-L-tyrosine; Downstream Products: 3,3',5'-Triiodo-L-thyronine, L-Thyronine, Levothyroxine sodium.
Data compiled from public chemical databases such as PubChem and supplier catalogs; supplier offers are provided by suppliers.
Last updated:
How to cite: Jingsj. "L-Thyroxine (CAS 51-48-9)". Jingsj Chemical Database. https://www.jingsj.com/compound/J-37899-4 (accessed 2026-11-09).
Data for reference only; verify product details with suppliers before purchase.