Melatonin promotes deeper sleep with more time in REM phases. Most dreams occur during REM sleep, so the more continuous time you spend in REM phases, the more likely you are to have dreams. For this same reason, vivid dreams and nightmares are a known side-effect associated with melatonin. However, melatonin isn’t why you have good or bad dreams, it’s just why you have more dreams, generally!(1) Bad dreams are most commonly the result of stress and anxiety.(2) Mella products use melatonin derived from St. John’s Wort, which is known to help destress and promote relaxation.(3) In our 4-week consumer panel, no panelists reported an increase in nightmares.