As many as one in three U.S. adults aren’t getting the seven to eight hours of sleep they need. Whether it’s a bombardment of stressful headlines, endless scrolling on a blue-light screen, or working into (or through) the night, our circadian rhythms are easily thrown off by modern life.

To fall and stay asleep, over six million American adults are turning to melatonin supplements, sold over the counter at pharmacies and grocery stores across the country.

Many of these users report side effects like nightmares. What’s causing them? And what’s in the melatonin tablets, liquids, and sprays we’re taking? 

Usually, side effects of melatonin include drowsiness and headaches, but experiencing vivid dreams and nightmares is certainly not