The melatonin hormone is connected to the Circadian Rhythm. The Circadian Rhythm can be known as the cycle that controls when we wake up or fall asleep. Melatonin specifically works with controlling sleep. It makes us feel tired or alerts our body when to go to sleep. It is made up of carbon (black), hydrogen (white), oxygen (red), and nitrogen (blue) atoms. Melatonin is a necessity as it warns us when we have to sleep. Without the melatonin hormone, our bodies would be unable to understand when we should go to sleep.