Unlike other sleeping pills, it isn't generally effective for hours. You cannot wait for it to make you tired. It varies with everyone, but for me melatonin kicks in after about an hour. It appears as a minor sleep "suggestion." You start thinking about sleep, but you won't fall asleep with a book on your face like excendrin PM or something like that. You should be in bed, with your eyes closed, 50 minutes after you take it. Then you fall asleep. If you try to finish the chapter you are reading or the TV show you are watching, you will miss the window and it won't work. For me, if I even wait until an hour and a half after I take it to close my eyes then it won't work. But otherwise I have found it to be the best sleep aid around. It isn't expensive, it isn't addictive, and it doesn't make you groggy the next day. I get a touch sleepy the first day that I use it if I haven't used it in a long time, but that goes away.

Melatonin = time-sensitive lullaby
Other sleep aids = hammer