L-cysteine hydrochloride monohydrate
Safe, but frequently animal-derived.
- Category
- Flour treatment agents
- Vegan
- maybe
- Vegetarian
- maybe
What it is
A form of the amino acid L-cysteine used to soften bread dough.
How it is used in food
A dough conditioner that relaxes gluten by breaking disulfide bonds, making industrial bread and pizza dough easier to machine and reducing mixing time and energy.
Commonly found in- Commercial bread
Health and safety
Safe for consumption. Vegans should ensure it is derived from microbial fermentation rather than animal sources.
Evaluated by JECFA and EFSA as a saf,e nutritionally normal amino acid with no numerical ADI required. It is an ordinary component of dietary protein, so additive amounts are negligible.
Regulatory status
| Region | Status | Notes |
|---|---|---|
| Australia & New Zealand FSANZ |
Permitted | Permitted under the FSANZ Food Standards Code. |
| European Union EFSA / European Commission |
Not approved | Not on the EU authorised list of food additives (Annex II). |
| United States FDA (Food and Drug Administration) |
Permitted | Authorised for food use by the FDA (often GRAS for standard additives). |
Identification on labels
- E-number
- E921
Worth knowing
L-cysteine was historically extracted from human hair and duck feathers — a fact that pushed manufacturers toward modern microbial fermentation, which also makes it vegan and halal/kosher friendly.
Conclusion
Safe, but frequently animal-derived.
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Open the appEntry last reviewed 2026-07-28.
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