MELATONIN & SLEEP: SCIENCE-BACKED, PLAIN-LANGUAGE GUIDE “Timing often matters more than dose.” The question “how many hours will it make me sleep?” is somewhat misleading. Melatonin is not a classic sedative with a predictable sleep-duration effect. Its primary action is helping the body transition into “biological night” and supporting sleep onset or circadian alignment. Sleep duration depends on sleep debt, evening light exposure, stress, caffeine/alcohol, and whether a circadian disorder is present. Some people fall asleep faster without a major change in total sleep time. Immediate-release products are typically aimed at sleep-onset; prolonged-release formulations may be more relevant for selected cases with frequent nighttime awakenings. If conditions such as sleep apnea, restless legs, mood disorders, or thyroid issues are present, melatonin alone may not resolve symptoms. The practical goal is a stable sleep–wake schedule rather than chasing a fixed number of hours. If you notice morning grogginess, headaches, vivid dreams, or daytime sleepiness, the dose and timing may need adjustment. For longer-term use, medical guidance is advised.