Teen insomnia. Story Source: NCBI Bookshelf. Lots of things you might do in the evening can make it hard for you to wind down and prevent you from falling asleep quickly. PLoS Med. Melatonin and another hormone, serotonin, help regulate a person's sleep—wake cycles. What can I do to start sleeping better again? But this is just an average. Skipping sleep can be harmful — even deadly, particularly if you are behind the wheel.