But is this melatonin side effect actually backed by science? Here’s what the research says. “This is critical for many functions,” Teitelbaum tells mbg, but, most importantly, for nudging us to sleep at nighttime. When the sun goes down and your space gets dark, that’s when melatonin can kick in and tell the body that it’s time for bed. What’s interesting is that most people associate melatonin with sleepiness, when the true parallel is between melatonin and a clock. According to Walker, those who feel like taking melatonin supplements makes them sleepy are actually experiencing a placebo effect. “There are a whole set of different chemicals and brain mechanisms that actually generate sleep and get you into sleep. Melatonin simply times when sleep is going to occur, not the generation of sleep itself,” he tells the outlet. This is one of a few reasons why other, non-melatonin supplements are typically more effective (not to mention, safer) for nightly sleep support. That being said, the jury’s still out on whether or not taking a melatonin supplement gives you crazy dreams. According to Darley, there isn’t enough solid research to suggest that taking melatonin would lead someone to have more odd dreams than usual. However, if you’re taking melatonin to get back on track after a period of suboptimal sleep, Medina tells mbg it is possible to have some weird dreams when you start sleeping more through the night. It’s also possible that someone taking melatonin would experience odd dreams because melatonin can lead to overactivation in different parts of the brain3. “There are melatonin receptors all over the brain in regions like the cortex, thalamus, substantia nigra, nucleus accumbens, amygdala, hippocampus, cerebellum, and your eyes,” Medina explains. “These are areas that are heavily involved in learning, memory, processing fearful events and threatening stimuli, stress relations, and cognitive executive function. So, when taking an amount of melatonin that is larger than what the body is used to, it is not surprising why these areas are overactive with the amount of melatonin that is available on the market.” Indeed, recent research shows that over the last 20 years, taking more than 5 milligrams of melatonin per day (much higher than the typical recommended dosage of 0.5 milligram, which is more closely aligned with human physiological levels of the hormone) has become more common in the U.S. This raises some safety concerns, as experts agree that taking high doses of any hormone—especially one that is as widespread as melatonin—can throw off your body’s natural hormone production. So while the science is limited on the direct link between melatonin and dreams, including the bad ones, there’s no denying that many people report having nightmares after taking this sleep aid, so more science is certainly warranted to suss out this apparent association or actual phenomenon.
