Is L-cysteine (E920) halal?

L-cysteine is doubtful in all four schools until its source is confirmed halal. A flour improver made from duck feathers, pig bristle or human hair, or by fermentation.

Doubtful · From the Halal or Not? rulebook, checked 28 September 2026 · Applies to food and drink

Verdict by school

SchoolVerdict
HanafiDoubtful
MalikiDoubtful
Shafi'iDoubtful
HanbaliDoubtful

Why

A flour improver made from duck feathers, pig bristle or human hair, or by fermentation. Human and pig sources are haram; feathers need halal slaughter; fermented is halal.

What to look for on the label

In cosmetics

Halal or Not? gives L-cysteine the same answer in cosmetics as in food.

Quick answers

Is L-cysteine (E920) halal?
L-cysteine is doubtful in all four schools until its source is confirmed halal. A flour improver made from duck feathers, pig bristle or human hair, or by fermentation.
What should I look for on the label?
Halal or Not? treats it as halal when the label also says: synthetic, fermentation, microbial, vegetable, plant, vegan. It is haram when the label says: human hair, pork, porcine, pig, swine, lard.

Sources

Halal or Not? reads an ingredients list against a published rulebook of where the four Sunni schools and the main certifiers agree and differ. It is information, not a fatwa. When in doubt, ask a scholar you trust or look for a recognised halal mark.

Ask Halal or Not? yourself

Paste a whole ingredients list, scan a barcode or type one ingredient, and see each school's verdict with the reason. Open Halal or Not?, free, no sign-up.

In Claude or any app that takes MCP connectors, add https://goodturn-mcp.pages.dev/halalornot/mcp and ask: “Is L-cysteine (E920) halal?”

More animal-derived additives