Levothyroxine

Drug ingredient

CAS 51-48-9

This chemical is an active pharmaceutical ingredient used in FDA-regulated drugs.

US productionNot reported

Import value, 2024$174M

Top sourceItaly 69%

This chemical is listed as active in US commerce, but no company reported it to EPA’s survey for 2019 or 2023. Sites may have made or imported less than the threshold amount, or none.

Why supply is unknown

Production is reported production, not a complete census of factories. Import value and source-country shares describe a shared customs category, not a separate chemical measurement.

Where It Comes From

Customs basis: HS 293790 · basket

These shares come from HS customs code 293790, which covers 10 tracked chemicals in total. They estimate the category's origin mix, not this chemical specifically.

Source Countries

Country of origin for US imports, from Census customs data (2024).

IT 69%ItalyCN 22%ChinaDE 3%GermanyIN 2%IndiaJP 2%Japan

Switzerland
Finland
Sweden
Canada
South Africa
Netherlands
Hungary
Spain
Argentina
Israel
Ecuador
South Korea
Poland

16 FDA-registered drug labelers

A-S Medication Solutions

Acella Pharmaceuticals, LLC

Apex Energetics Inc.

Asclemed USA, Inc.

BioActive Nutritional

Bryant Ranch Prepack

Calvin Scott & Co Inc.

DIRECT RX

Energique, Inc.

Genus Lifesciences

Guna spa

Northwind Health Company, LLC

NuCare Pharmaceuticals,Inc,

Sichuan Xinchuanyi Biotechnology Co., Ltd

The Wellness Center for Research and Education

Trifluent Pharma, LLC

Why It Matters

Sectors

Health

Downstream Uses

Appears in 23 drug and cosmetic product listings (FDA).

•NP Thyroid 60
•NP Thyroid
•EvexiTHROID
•NP Thyroid 30
•Thyroid HP
•GUNA-Lympho
•GUNA Lympho Detox
•NP Thyroid 90

Show all 23

•Thyropar
•Mitochondria PRO
•Neurotransmitter Pro
•NP Thyroid 15
•RenThyroid
•NP Thyroid 120
•Intestine Formula
•GUNA-Geriatrics
•Thyro T3 Rescue
•R20 Testogen
•R06 Thyroid
•Thyroid Formula
•Thyroxine Cord
•Thyroplex
•R08 Lymphatics

FDA Shortage Status

Whether any manufacturer currently reports this drug as in shortage on the FDA Drug Shortages database. "Active Shortage" means at least one presentation has status "current."

No Shortage

Shortage History

Rows group FDA shortage filings by drug product. Each manufacturer makes its own FDA shortage filing, so one product can carry several reports at once: Available, Limited Availability, Unavailable or to be discontinued.

to be discontinued
Levothyroxine Sodium Tablet
Shortage listed since July 10, 2025

See all current drug shortages

Chemical Identity

CAS51-48-9

PubChem CID5819

DTXSIDDTXSID8023214

FormulaC15H11I4NO4

Mol. Weight776.87 g/mol

SMILESC1=C(C=C(C(=C1I)OC2=CC(=C(C(=C2)I)O)I)I)CC(C(=O)O)N

Data Sources

PubChem · compound 5819Retrieved 2026-04-07
EPA TSCA InventoryRetrieved 2026-04-24
FDA Drug ShortagesRetrieved 2026-10-04
US Census international tradeReporting year: 2024 · Retrieved 2026-10-04

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Brief citations

Levothyroxine (CAS 51-48-9) https://chemicalindependence.com/chemical/51-48-9/ PubChem: 5819. Retrieved 2026-04-07. https://pubchem.ncbi.nlm.nih.gov/compound/5819 EPA TSCA Inventory: CAS 51-48-9. Retrieved 2026-04-24. https://www.epa.gov/tsca-inventory FDA Drug Shortages: CAS 51-48-9. Retrieved 2026-10-04. https://www.accessdata.fda.gov/scripts/drugshortages/ US Census international trade: HS 293790 for CAS 51-48-9. Reporting year: 2024. https://usatrade.census.gov/