Melatonin works better if you can avoid exposure to light. It doesn't make you go to sleep, but it makes it easier to go to sleep. If you stay active, you can over-ride melatonin and stay awake. Dosages can vary wildly. I have seen supplements with as little as 0.5 mg, but usually I find 1 - 3 mg supplements in stores. There used to be a tea by Celestial Seasonings with melatonin in it; it doesn't really have any taste. They stopped making it, and I have found that dissolving melatonin in tea just isn't the same somehow. It isn't something I take often, but you can take it daily. Infrequent use just seems to keep it working better for me.