L-Cysteine ኬሚካላዊ ቀመር HO2CCH (NH2) CH2SH ጋር α-አሚኖ አሲድ ነው እና ኢ ቁጥር E920 የተመላከቱ ነው.
L-Cysteine yi acid α-acid kunye HO2CCH ifomula yemichiza (NH2) CH2SH kwaye luchazwa yi E920 inombolo E. Le yenye kwiibloko zokwakha protein kwaye kubalulekile ekuvelisweni Antioxidants.