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E402ThickenerLow concern
Potassium Alginate
In plain words
The short version
The potassium salt of seaweed alginate — a thickener and gelling agent used like sodium alginate.
Why it's green
It's widely considered safe at the amounts used in food, so we mark it green. The Safety section below has the details.
Safety profile
No ADI specified. Not digested; behaves as soluble fiber.
The detail
The potassium salt of alginic acid from brown seaweed.
Thickener, stabilizer, and gelling agent — used like sodium alginate where a potassium (rather than sodium) salt is preferred, e.g. in reduced-sodium formulations.
White-to-yellow water-soluble powder giving viscous solutions; gels with calcium.
Permitted in the EU, the US, and globally.
Sources
- EFSA ANS Panel — Re-evaluation of alginic acid and its sodium, potassium, ammonium and calcium salts (E 400–E 404) as food additives (2017) — European Food Safety Authority (EFSA Journal 2017;15(11):5049), 2017. Safety: no ADI specified / no numerical ADI needed
- WHO JECFA database — Potassium alginate (INS 402) — Joint FAO/WHO Expert Committee on Food Additives (WHO), 1992. Safety: ADI not specified
- 21 CFR 184.1610 — Potassium alginate (eCFR, current as of 13 Oct 2026) — US eCFR / Office of the Federal Register, 2026. Origin and US regulation: potassium salt of alginic acid from brown algae; GRAS with use limits
- EUR-Lex — Regulation (EC) No 1333/2008 on food additives, consolidated version of 18 August 2026 — Publications Office of the European Union, 2026. Regulation: permitted in the EU
Checked against these sources on .
Educational information only. Not medical, dietary or veterinary advice. Spotted an error? Tell us.