Zenegra 50 can be effective in improving erectile function and helping men with mild to moderate ED achieve and sustain erections suitable for sexual activity. It should be taken approximately 30 minutes to an hour before planned sexual activity. Zenegra 50 contains a 50 mg dose of sildenafil citrate, which is a standard starting dose. Depending on individual response and tolerability, a healthcare provider may adjust the dosage up or down.