Additives
L-Cystine (E921): What It Is and Is It Safe?
Safe
Flour Treatment Agent
L-cystine is a naturally occurring sulphur-containing amino acid, the oxidised dimer of L-cysteine, used as a dough conditioner and nutrient. The body metabolises it as a normal dietary amino acid. EFSA and JECFA regard cysteine and cystine as safe at food-additive use levels.
- Category
- Flour Treatment Agent
- Typically used in
- Dough conditioner; amino-acid nutrient.
- Regulatory status
- Recognised as safe; the closely related L-cysteine E920 is the authorised EU/UK flour-treatment form.
Scrannr flags L-Cystine automatically when you scan a barcode.
Sources
Where this comes from
- EFSA (2006) — Opinion on the use of L-cysteine in foods intended for infants and young children https://efsa.onlinelibrary.wiley.com/doi/pdf/10.2903/j.efsa.2006.390
Products
Products containing L-Cystine
We're building product pages that show real UK products containing L-Cystine, using Open Food Facts data. They'll appear here soon — in the meantime, scan any barcode with the Scrannr app to check for it instantly.
Let Scrannr read the label.
Scan a barcode and get the additives flagged in plain English, plus a clear health score. Free to download.