Methionine, cysteine and MSM from China

0% or 6%, with suspensions

Read from the UK Trade Tariff on 26 September 2026, methionine as an INN substance and the methionine hydroxy analogue carried 0% duty on goods from China, and other methionine carried 6% but entered at 0% under a suspension to 31 December 2026. Cysteine, cystine and their derivatives carried 0% for pharmaceutical use under additional code 2500 and 6% otherwise. MSM (dimethyl sulfone), glutathione and thiourea carried 6% but entered at 0% under suspensions to 31 December 2028. No anti-dumping measure applied.

Suspensions apply to the chemical itself, not to mixtures or preparations, so a methionine premix or a finished supplement is classified by what it is. Confirm the commodity code. Our amino acids and protein guide covers plant proteins.

Feed, food and supplement rules

Methionine sold for animal feed must be an authorised feed additive under retained Regulation 1831/2003, bought against the specification in its authorisation and labelled accordingly. L-cysteine used by bakers is the flour treatment agent E 920, and its purity specification is in the GB Register of Food Additive Authorisations.

Before selling MSM, glutathione or another sulphur compound as a food supplement, check whether it is a novel food and, if so, whether it is authorised for that use in Great Britain; an ingredient without authorisation cannot be sold as food however pure it is. Industrial grades such as thiourea and rubber accelerators need a UK REACH position and safety data sheets; see our UK REACH guide.

Worked duty example

Suppose, purely for illustration, you import 25 tonnes of DL-methionine feed grade under 2930 40 90 00. At £60,000 free on board and £2,500 to ship and insure, the customs value is £62,500. Methionine at 6% pay £3,750 of duty; VAT is then worked out on value plus duty, £66,250, giving £13,250. Of the £17,000 paid at import, only the £3,750 of duty stays a cost for a VAT-registered business. Under the suspension that runs to 31 December 2026, the same methionine enters at 0%, so the duty line above applies only to entries after that date if the suspension is not renewed. The method is set out in how UK import duty and VAT work.

What goes wrong

Sulphur amino acids fail on assay, source and paperwork. Methionine or cysteine assays below the grade; cysteine made from human hair or feathers is sold to buyers who need a plant or fermentation source for halal, kosher or vegetarian claims; food and supplement lots arrive with a certificate for a feed-grade batch; and powder cakes because of moisture.

Test each lot at an accredited laboratory for assay, specific rotation for L-forms, heavy metals and loss on drying against the grade, ask for a signed statement of the raw material and process for cysteine, match batch numbers on the bags to the certificate, and check feed additive and food supplement documents before the goods ship.

Cambridge China Bridge sources methionine, cysteine, MSM and other sulphur chemicals for feed mills, bakeries, supplement brands and rubber compounders, checking the producer's grade and records first. See how we verify a producer.