Men with this condition are unable to achieve and sustain a powerful erection during sexual activity. The absence of blood flow to the penile region during sexual stimulation could be one cause of this kind of dysfunctional sexual behavior. Sildenafil, an ingredient in Malegra 100 , helps men achieve longer, stronger erections during sexual activity. Consume this medication with water; do not crush or chew the tablet. This medication takes 4 to 6 hours to take effect.