This supplement continues to work as long as you take it. Your body doesn’t develop a tolerance for these ingredients because one is a hormone your body makes naturally. The others are natural herbs that don’t accumulate in your body and become less effective over time. As for the immediate effect, it varies from person to person. It doesn’t cause you to stay asleep for a certain amount of time because it isn’t a sleeping pill. It does help you to develop a routine trough.