Cysteamine Products | Cleanchem - Cysteamine is a sulfur-containing compound used primarily in the treatment of cystinosis, a rare genetic disorder that causes cystine accumulation in cells. It works by breaking down cystine crystals and preventing organ damage, especially in the kidneys. Cysteamine is available in both oral and topical formulations, with the latter being used to treat eye-related symptoms of cystinosis. Side effects can include gastrointestinal issues, headaches, and skin irritation.