Melatonin is also used to alleviate jet lag. I use melatonin when I travel overseas sometime to help with getting my sleeping pattern on track. Once you take a dose of melatonin, you will start to feel slighty drowsy and if it happens to be during the day, and you close your eyes, guess what.... you will fall asleep. I would not recommend taking melatonin during the day due to the fact that you will feel drowsy once you wake up about an hour later, such as during a lunch break.