More melatonin did not mean more sleep, and 30 minutes was late

Melatonin is usually bought at whatever dose the bottle suggests and swallowed half an hour before bed. Across 26 trials the effect stopped climbing near 4mg a day, and shifting the dose to roughly 3 hours before bed left people falling asleep faster and sleeping longer. That pairing is the peak of a curve drawn across differing trials, never run head to head against the usual timing. The number on the bottle was never the variable that mattered most.