KFD Melatonin is a dietary supplement containing melatonin. Melatonin is a hormone produced by a small gland in our brain - the pineal gland. It is also a powerful antioxidant 1 Melatonin supplementation may be of interest to people whose sleep is not deep enough and falling asleep is a problem. Melatonin should facilitate a good night's sleep without affecting the negative mood of the next day. Melatonin supplementation can bring many benefits, especially for people who work shifts or change time zones (and feel the so-called jet-lag). It is worth noting that the package containing as many as 200 capsules can last a long time.