The FDA discovered this substance while looking into international postal shipments. African Superman Suppliers include sildenafil, the active component of the FDA-approved prescription medication Viagra, which is used to treat erectile dysfunction, according to FDA laboratory testing (ED). This unlisted component may interact with the nitrates in several prescription medications, including nitroglycerin, and cause dangerously low blood pressure. Nitrates are frequently taken by men who have diabetes, high blood pressure, high cholesterol, or heart disease.