During the night cycle, the body begins to release THIS HORMONE (C13 H16 N2 O2) which gives off the "drowsy" effect. Its name can be sometimes confused with another, more dark compound found elsewhere in the human body. (edited at 1:13 pm, April 12, 2017 (EDT))
Original question: During the night cycle, the body begins to release THIS HORMONE (C13 H16 N2 O2) which gives off the "drowsy" effect. It's name can be sometimes confused with another, more dark compound found elsewhere in the human body.
melatonin [as opposed to melanin, which is skin pigment]