I-L-Cysteine yenye ye-20 yendalo ye-amino acids kwaye, ngaphandle kwe-methionine, kuphela equlethe isulfure.Yi-thiol-equlathe i-amino acid engeyomfuneko edityanisiweyo ukuze yenze i-Cystine.I-amino acid engabalulekanga yesulfure-equkethe i-amino acid kubantu, ehambelana ne-cystine, i-Cysteine ibalulekile kwi-protein synthesis, i-detoxification, kunye nemisebenzi eyahlukeneyo ye-metabolic.Ifunyenwe kwi-beta-keratin, iprotheni ephambili kwizipikili, ulusu, kunye neenwele, i-cysteine ibalulekile kwimveliso ye-collagen, kunye nokuqina kwesikhumba kunye nokuthungwa.