Sourcing L-isoleucine from China

L-isoleucine classification and duty

Read from the UK Trade Tariff on 1 October 2026, heading 2922 covers oxygen-function amino-compounds. The supplied data has no named L-isoleucine line; the candidate residual amino-acid code is 2922 49 85 90. It carries 0% duty for China, with no anti-dumping or countervailing duty and no suspension listed. Only the relevant residual line is shown here.

The tariff attaches veterinary control to this line. Ask your customs broker to confirm its application to the Chinese material using the manufacturing route and animal-origin declaration. Where veterinary checks apply, animal products must enter through an approved border control post. The data also lists an export waste control; confirm its relevance with your broker if material is being returned or shipped as waste.

Give your broker the identity, composition, manufacturing route and intended use before confirming the code through finding your commodity code. Blends and finished supplements need a separate classification check. See the wider amino-compounds guide for other substances in this heading.

Specify L-isoleucine identity and grade

Specify L-isoleucine rather than an unspecified isoleucine grade or an amino-acid blend. Agree identity testing, optical rotation or another suitable stereochemical identity method, assay basis, related amino acids, moisture, particle size and appearance. Ask for the manufacturing route, raw-material origin and a certificate of analysis for the actual batch.

State whether the powder is for food formulation, feed or laboratory use. Do not accept a technical-grade certificate as evidence of suitability for food. For chemical imports, confirm with HSE whether UK REACH registration is required and whether an exemption applies. Settle the applicable exemption before relying on it.

For supplement use, review the proposed claims before approving artwork. A supplement claiming to prevent, treat or cure human disease may be classified as a medicine. Agree the testing plan through testing and certification.

Worked duty example

Illustrative example, not a quote: Illustrative bulk order of L-isoleucine powder in lined bags under 2922 49 85 90, invoiced at £30,000 free on board, with £2,500 of freight and insurance to the UK. The customs value is £32,500. Duty at 0% is £0. Import VAT at 20% is charged on the customs value plus duty, £32,500, so it is £6,500. 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 purchase specification, bag labels, laboratory identity result and batch certificate all identify L-isoleucine.

Batch results: check assay basis, stereochemical identity, related amino acids and moisture against the agreed methods and acceptance criteria.

Food suitability: check the agreed microbiological and contaminant results on the shipped batch where the intended use is food.

Arrival condition: check inner seals, wet bags, caking, foreign material and batch traceability; retain a representative sample before releasing stock.

What goes wrong

An assay result alone can leave stereochemical identity or related amino acids unresolved. A generic certificate may describe a typical product rather than the shipped lot. Require batch-specific results and investigate discrepancies before using the powder.

Damaged liners and damp bags can leave powder caked or contaminated. Record arrival condition and hold suspect stock separately. Avoid approving food use, supplement claims or customs paperwork solely because the supplier calls the product food grade.

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.