E920 · L-cysteine
We haven’t recorded a regulator assessment for L-cysteine yet. The information below comes from our ingredient database; a verdict will appear here once EFSA, FDA or WHO positions are added.
What is E920?
L-cysteine is a sulfur-containing amino acid naturally found in protein-rich foods. As a food additive, it is used mainly as a dough conditioner to improve the elasticity and texture of bread and baked goods, and it also serves as a precursor for the antioxidant glutathione in the body. It is generally recognized as safe by EFSA and the FDA. Commercially, food-grade L-cysteine is most commonly manufactured from human hair, duck/chicken feathers, or petrochemical/bacterial fermentation sources — rarely from poultry or eggs directly — so its origin matters for some consumers.
Also appears on labels as: L-cysteine, L cysteine, Lcysteine, L–cysteine, L-cystein, L-cystein hydrochloride, L-cysteine HCl, L-cysteine monohydrochloride, E920, E 920, E-920, Cysteine.
What the evidence says
- Commercial L-cysteine (E920) is frequently derived from human hair or poultry feathers, which is a concern for vegans, vegetarians, and some religious dietary observers; fermentation-derived (non-animal) sources exist but are less common and not always disclosed.
- Generally recognized as safe at typical dough-conditioning levels.
Research behind the verdict
- Re‐evaluation of L‐cysteine hydrochloride monohydrate (E 920) as a food additive — EFSA Panel on Food Additives and Flavourings (FAF), EFSA Journal (2021). The Panel on Food Additives and Flavourings (FAF) provided a scientific opinion re‐evaluating the safety of L‐cysteine hydrochloride monohydrate (E 920) as a food additive. L‐cysteine is a naturally occurring amino acid. The Panel concluded that there is no need for a numerical ADI for L‐cysteine and there is no safety concern for the general population when L‐cysteine is used as a flour treatment agent.[safe]
Frequently asked questions
Is E920 safe?
Our overall verdict for E920 (L-cysteine) is “Not yet rated”, based on the most cautious of the major regulators’ positions — no regulator assessment is recorded in our database yet.
Is E920 vegan, halal or gluten-free?
According to our ingredient data for L-cysteine — vegan: no, vegetarian: no, halal: no, kosher: no, gluten-free: yes, dairy-free: yes. Manufacturing sources can vary between products; check the label if it matters to you.
What is E920 and why is it used?
L-cysteine is a sulfur-containing amino acid naturally found in protein-rich foods. As a food additive, it is used mainly as a dough conditioner to improve the elasticity and texture of bread and baked goods, and it also serves as a precursor for the antioxidant glutathione in the body. It is generally recognized as safe by EFSA and the FDA. Commercially, food-grade L-cysteine is most commonly manufactured from human hair, duck/chicken feathers, or petrochemical/bacterial fermentation sources — rarely from poultry or eggs directly — so its origin matters for some consumers.
Does E920 contain allergens?
No known allergens are recorded for L-cysteine.
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This page summarises publicly available regulatory assessments and research. It is general information, not medical advice. Sources: EFSA, FDA, WHO and the studies linked above.