Melatonin might be the most commonly reached-for sleep supplement on the market, and also one of the most widely misunderstood. It's often treated like a sedative — something that simply knocks you out — when its actual biological role in the body is genuinely quite different from that.
What melatonin actually is: a hormone your body produces naturally in response to darkness, signaling to your internal clock that it's time to begin winding down for the night. It's fundamentally a timing signal, not a sedative in the pharmacological sense — its core job is telling your body when sleep should happen, not forcibly making sleep happen regardless of other conditions.
This distinction is exactly why melatonin supplements work well in some situations and considerably worse in others. They tend to be genuinely useful for shifting sleep timing specifically — jet lag recovery, adjusting to a new shift-work schedule, or a body clock that's gradually drifted later than desired over time. They're far less reliable as a general-purpose "I simply can't fall asleep" fix, because if your internal timing is already fine and something else entirely — stress, an uncomfortable room, mouth breathing — is the actual barrier to sleep, adding more of a timing-signal hormone doesn't address the real underlying problem at all.
Dosing is also widely misunderstood, and worth knowing about directly. Many over-the-counter melatonin products are dosed considerably higher than what research actually suggests is effective for its intended purpose — more isn't better here, and higher doses are more strongly associated with next-day grogginess than with meaningfully better sleep quality overnight.
The honest takeaway: melatonin is a real, genuinely useful tool for one specific job — realigning your body's internal clock — rather than a general-purpose sleep aid for any and every sleep problem. Expecting it to fix an unrelated underlying issue is where most disappointment with it tends to come from.