I’ve been using Sildenafil (generic Viagra) for a couple of months now and it’s working as intended. It works best on an empty stomach, so if you know when you’ll be going out you can plan ahead and take it as needed. For myself, I’ve found about 45 minutes beforehand works best. Took mine last night and got two pops off within an hour, both times rock solid. Each time lasted longer than expected. To counter the headaches I take two Tylenol about thirty minutes before, but the stuffy nose comes a couple of hours later.