Sourcing levothyroxine sodium from China

Duty and controls for levothyroxine sodium

Read from the UK Trade Tariff on 7 October 2026, heading 2937 covers hormones and their derivatives and structural analogues, alongside prostaglandins, thromboxanes and leukotrienes. For levothyroxine sodium active ingredient, check the residual line 2937 90 00 00 against the precise composition and presentation. The table shows purchasing specifications within this candidate line, rather than separate tariff subdivisions. See the wider hormones and steroids guide.

The supplied tariff snapshot records 0% duty from China for this line, with no anti-dumping or countervailing duty and no suspension. It attaches Home Office controlled-drug import and export flags, plus an export waste-control flag. Controlled-drug or precursor imports require licensing where applicable. Ask your customs broker to confirm whether the import flag applies to the exact substance; also confirm the export flags before any return shipment.

Confirm the commodity code using the substance identity, composition and intended presentation. This guide concerns the active ingredient supplied to a business, rather than finished tablets. Medicines made up in measured doses fall under heading 3004, while bulk medicament mixtures fall under heading 3003. An ingredient's tariff treatment does not replace checks on the importer and pharmaceutical documentation.

Specify the sodium salt and assay basis

For human-medicine use, active-substance importers must be registered with MHRA. Confirm the applicable good manufacturing practice requirements with MHRA. For Chinese supply, establish the written-confirmation route with MHRA before shipment. Where a written confirmation is required, obtain it from the issuing authority in the exporting country.

Name levothyroxine sodium explicitly in the purchase specification. Agree the pharmacopoeial monograph, hydration state, assay calculation basis, related substances, residual solvents and particle-size requirements. Specify whether micronisation is needed. Ask the intended medicine manufacturer to approve these details, the retest date, storage conditions and documents for its regulatory file.

Identify the actual manufacturing site rather than relying on a trader's name. Match the batch certificate of analysis to that site and the agreed specification. Agree sealed packing and handling arrangements for the potent ingredient, then review the producer through factory verification.

Worked duty example

Illustrative example, not a quote: 25 kg of levothyroxine sodium active ingredient; illustrative order and values under 2937 90 00 00, invoiced at £40,000 free on board, with £800 of freight and insurance to the UK. The customs value is £40,800. Duty at 0% is £0. Import VAT at 20% is charged on the customs value plus duty, £40,800, so it is £8,160. With no duty, the only import tax is the VAT, which a VAT-registered importer can usually reclaim. The import duty and VAT guide explains each step.

Inspection checklist

Identity: check that the order, container labels and analysis certificate all name levothyroxine sodium, with the agreed hydration state and matching batch identity.

Documents: check the manufacturer's good manufacturing practice evidence, batch certificate, retest date and the agreed import-document package.

Laboratory: arrange independent sampling for identity, assay, related substances and residual solvents; check water content and particle size against the purchase specification.

Packing: inspect seals, labels and evidence of storage or transport departures from the agreed conditions. Record damaged containers before opening. See quality inspection explained.

What goes wrong

A quoted assay can appear acceptable while using a different calculation basis from the buyer's specification. Unclear hydration state, unapproved particle size and incomplete impurity results can leave the medicine manufacturer unable to accept the batch. Agree the test methods and reporting basis before approving a sample.

Documents can describe a different manufacturing site or fail to match the delivered batch. Resolve missing pharmaceutical documents and any tariff-control uncertainty before dispatch. Keep material with damaged seals or unresolved test discrepancies separate while the intended manufacturer decides whether it can be accepted.

Cambridge China Bridge sources these products for UK businesses, checking the factory and the documents before shipment. See factory verification. For repeat volumes, see container programmes.