Is L-cysteine Halal?
Status: Haram
L-cysteine is considered haram (not permissible). Amino acid often sourced from human hair or poultry feathers.
Why this status?
Amino acid often sourced from human hair or poultry feathers. Haram unless certified plant/microbial origin.
Sources
Classification based on clinical nutrition assessment; no independent published study cited.
Reviewed by Habib Aman, Islamic Scholar, MBA — last reviewed September 27, 2026.
This is general guidance for everyday shopping, not a religious ruling. Formulations vary by manufacturer and country — confirm with the manufacturer or your local scholar when it matters.
Checking a whole product?
SafaScan is a halal scanner app that is coming soon. It will check L-cysteine and every other ingredient on a product. Sign up for launch updates. Learn about SafaScan.
Try SafaScan