Most people take melatonin right before bed. That might be one of the worst times to take it. Melatonin isn't a sedative, it's a chronobiotic. It doesn't knock you out. It signals to your circadian clock that it's dark. And the effect it has on your sleep timing depends entirely on WHEN you take it. There's a concept called the Phase Response Curve. It shows that melatonin taken ~3 hours before your usual bedtime produces the largest phase advance, meaning it shifts your internal clock earlier, so you fall asleep sooner and wake up easier. But take it AT bedtime? You can actually push your clock in the wrong direction. That's a phase delay. You end up falling asleep later over time, not earlier. The sweet spot sits just before dim light melatonin onset, the point when your brain would naturally start releasing melatonin. For most people, that's roughly 3 hours before habitual bedtime. Timing > dose. Lewy et al. (1998), Burgess et al. (2010), and Challet et al., J Pineal Res (2024).