What is E403?
E403 is Ammonium alginate, a food additive used as a thickener. Plant (seaweed).
Also written as: INS 403, E-403, E 403. INS is the international numbering system used outside Europe, including on labels in Asia, Australia and the Middle East.
What to do
No action needed for this additive. Check the rest of the ingredient list, and remember that meat products still need proper halal slaughter.
Is E403 vegetarian or vegan?
Yes. E403 (Ammonium alginate) is normally made from plant, mineral, microbial or synthetic sources, so it is suitable for vegetarians and vegans.
Why we classify it this way
Halal Plant (seaweed).
Basis: No concern found. Made from plants, minerals, fermentation or synthesis, or from a permitted animal product. Nothing in normal production raises a pork, alcohol, insect or slaughter question.
No external reference is listed for this record yet.
Classification audited 3 November 2026. It has not been reviewed by a scholar. How classifications work · Suggest a correction
Frequently asked questions
Is E403 halal?
E403 (Ammonium alginate) is halal. Plant (seaweed).
What is E403 made from?
Seaweed.
What is E403 used for?
E403 is used as a thickener, typically in desserts, sauces, dairy products, ice cream and soups.
What should I do if a product contains E403?
No action needed for this additive. Check the rest of the ingredient list, and remember that meat products still need proper halal slaughter.
Is E403 vegetarian or vegan?
Yes. E403 (Ammonium alginate) is normally made from plant, mineral, microbial or synthetic sources, so it is suitable for vegetarians and vegans.