Common Strengths: The most common formulation is 50mg Sildenafil + 30mg Dapoxetine or 100mg Sildenafil + 60mg Dapoxetine. How it Works: Sildenafil acts as a PDE5 inhibitor (increasing blood flow), while Dapoxetine is a selective serotonin reuptake inhibitor (SSRI) that delays ejaculation. Effectiveness: It has been reported to help approximately 80% of men experiencing sexual difficulties. Onset & Duration: The medication typically starts working within 30–60 minutes (some reports say 15 minutes) and effects can last for up to 4–5 hours.