Most people know that melatonin is a hormone that helps regulate sleep, but many may not realize that it can also be taken as a supplement every night to help improve overall sleep quality. While melatonin is most commonly used to treat disorders such as sleep apnea or jet lag, taking it nightly can have other benefits such as improving mood and reducing anxiety. However, like any supplement, it is important to speak with a health professional before starting this routine if you are particularly sensitive to the side effects of melatonin.