Cystine-depleting agents are substances that reduce the levels of cystine, a naturally occurring amino acid in the body. These agents are often used in medical treatments, particularly for conditions like cystinuria, a genetic disorder that leads to the formation of kidney stones due to excess cystine. By lowering cystine levels, these agents help prevent stone formation and improve patient outcomes. Common cystine-depleting agents include penicillamine and tiopronin. These medications work by promoting the excretion of cystine in the urine, thereby decreasing its concentration in the body. While effective, they may also have side effects, so monitoring by healthcare professionals is essential during treatment.