According to the CDC, about 70 million Americans have chronic sleep problems. Out of the desire for sweet sleep, many people are trying to take the hyped melatonin to improve sleep. The national health interview survey found that its use in the United States more than doubled between 2007 and 2012. However, what exactly is melatonin? It is a hormone naturally produced by the human body. It lets us know it's time to go to bed.