Soy leghemoglobin

Soy leghemoglobin is the iron-carrying protein that makes plant-based burgers look and bleed like meat. It is the colour most people have eaten without knowing it has a colour additive listing at all.

Where it is and isn’t permitted

Status of Soy leghemoglobin by jurisdiction. Every jurisdiction this site covers is listed, including those where the substance does not appear.
JurisdictionStatusScope and limitsCitation
United StatesFood and Drug AdministrationPermitted21 CFR 73.520retrieved 2026-09-07
Codex AlimentariusCodex Alimentarius Commission / JECFANot listedDoes not appear on this jurisdiction’s permitted list. That is not the same as being prohibited.

What it is made from

Produced by fermentation with genetically engineered Pichia pastoris yeast carrying the gene from soybean root nodules, rather than extracted from soy plants. The protein is the same one the plant makes; the production route is not.

  • Vegan
  • Vegetarian

Every name it appears under

1 recorded name. A label may use any of them.

As it appears in regulation

  • Soy leghemoglobin

Hazard reference values

No reference value for this substance in the sources we hold.

Evidence and how bodies read it

Studies, and the differing conclusions regulators drew from them, are curated by hand rather than machine-read, and none has been written for this substance yet.

Sources for this page

  • ecfr retrieved 2026-09-07

Full licence terms and publisher details on Sources. How this page is built and updated: Method.

Machine-readable:/api/v1/additives/soy-leghemoglobin.json