MELATONIN & SLEEP: SCIENCE-BACKED, PLAIN-LANGUAGE GUIDE “The most reliable sleep aid is often a consistent rhythm—not a single tablet.” Melatonin does not guarantee sleep. It is not a classic hypnotic sedative; it signals “biological night” and helps align circadian timing. When taken at the right time, it may help sleep onset; taken at the wrong time, it can backfire. And if the real causes of insomnia (stress, anxiety, depression, pain, sleep apnea, late-night screens) aren’t addressed, expecting certainty is unrealistic. Some people respond very well—especially those with delayed schedules, jet lag, or circadian misalignment—while others feel little effect. So “definitely” is the wrong benchmark; “meaningful in the right indication” is more accurate. For best results, combine melatonin with dim evening light, consistent bed/wake times, caffeine control, and a calming routine. If there’s no meaningful improvement within 1–2 weeks, evaluate underlying causes and consider evidence-based approaches like CBT-I.