I have a mild ED problem and have been experimenting with doses. I get a good erection in about 30 minutes with 1/4 of a 50 mg pill, a little stronger with 1/2 of a 50mg pill. In my case at age 59 it takes me about 20 minutes to get hard a second time. The next day I often wake with a powerful erection and can often have sex later that day with no pill at all. I would rather have sex much more often than wear my wife out with a cock that won’t go down.