Hell the one time I used it I used 10mg about 30 minutes before action, on a friday night, and I had a tough time keeping it down till tuesday morning! Lol, of course, I was on cycle at that point, on test, 21years old. I'd just taken 4 or 5 soma's and couldn't get it up, so when my girl wanted to get it on I took a little cialis to counteract the soma's... once they wore off, the cialis didn't lol! I'd go with Mr.X suggestion...20-25mg 1-2hrs before action.