Melatonin is a naturally occurring hormone secreted by your body’s pineal gland. At nighttime, your body begins to secrete melatonin to help make you sleepy. In the morning, your body lowers the amount of melatonin in your system to help you wake up. ZzzQuil PURE Zzzs not only has melatonin, but it also contains a unique drug-free blend of botanicals, like chamomile, lemon balm, valerian root and lavender.