Malegra 25 mg is primarily prescribed to men who have difficulty achieving or sustaining an erection sufficient for sexual intercourse. It is considered an effective treatment for ED. The active ingredient in Malegra 25 mg, Sildenafil Citrate, works by inhibiting PDE5, the enzyme responsible for breaking down cyclic guanosine monophosphate (cGMP). Elevated levels of cGMP relax the blood vessels in the penis, allowing for improved blood flow and an erection.