Tadarise 2.5 mg can start working within 30 minutes to 1 hour after taking the medication. However, it's important to note that sexual stimulation is necessary for tadalafil to be effective. Without sexual arousal, the medication alone may not lead to an erection. Tadarise 2.5 mg contains tadalafil, which works by increasing blood flow to the penis during sexual stimulation. This helps men achieve and maintain an erection suitable for sexual activity.