Abstract: Cysteine compositions comprising less than about 400 ?g/L of aluminum. For example, solutions of cysteine comprising a pharmaceutically acceptable solvent, cysteine, and less than about 145 ?g/L of aluminum, wherein the solution is devoid of visible particulate matter. Cysteine compositions described herein may be suitable for injection. For example, disclosed cysteine solutions may be provided intravenously to meet amino acid nutritional requirement in individuals receiving total parenteral nutrition. Also provided are processes for preparing cysteine compositions, and methods for providing cysteine to individuals in need thereof.