Cenforce 25 mg usually does not lose its effectiveness at a specific, predictable time. If it contains sildenafil, its effect typically lasts around 4 hours, although the strength of the effect varies from person to person. Onset: Usually 30–60 minutes after taking it. Strongest effect: Often around 1 hour after taking it. Duration: It may help with erections for up to about 4 hours, but this does not mean you will have a continuous erection. After the effect wears off: The medicine's ability to help you achieve an erection decreases. ***** stimulation is still needed for it to work. A heavy or fatty meal can delay how quickly sildenafil starts working, and alcohol may make erections more difficult. nhs.uk +1 If you mean the tablet's expiry date: check the expiry printed on the package. Do not use it after that date. If Cenforce 25 mg has stopped working as well as before, don't take an extra tablet or increase the dose yourself.