Tadarise 20 mg contains Tadalafil, which works by inhibiting the enzyme phosphodiesterase type 5 (PDE5). This enzyme typically breaks down cGMP, a molecule responsible for relaxing the smooth muscles and blood vessels in the penis. By blocking PDE5, Tadarise 20 mg helps increase the levels of cGMP, promoting better blood flow to the penis and facilitating an erection when sexually stimulated.