Melatonin is the most popular sleep supplement in the world, and most people are taking too much, too late, and for the wrong reasons. Here's what the science actually says.
What Melatonin Does (and Doesn't Do)
Melatonin is not a sedative. It doesn't knock you out. It's a timing signal — a hormone that tells your brain "it's nighttime now." Your body naturally produces melatonin as light dims in the evening. Supplemental melatonin can shift when your body thinks nighttime starts, which is useful for jet lag, shift work, and delayed sleep phase — but it's not a fix for general insomnia.
The Right Dosage Is Lower Than You Think
Most melatonin supplements come in 3mg, 5mg, or 10mg doses. Research consistently shows that 0.3mg to 0.5mg is the physiologically effective dose — the amount that raises your blood melatonin to natural nighttime levels. Higher doses can actually be counterproductive, causing grogginess, disrupting your natural production cycle, and reducing effectiveness over time.
If you're taking 5–10mg and it's "not working anymore," the dose is likely the problem. Try cutting down to 0.5mg.
Timing Matters More Than Dose
Take melatonin 30–60 minutes before your target bedtime. Taking it too early makes you groggy before you're ready for bed. Taking it as you're already lying in bed is too late — it needs time to reach effective blood levels.
For circadian shifting (like after travel), take it 2–3 hours before your desired new bedtime for several consecutive nights.
Side Effects
At appropriate doses, melatonin has very few side effects. At high doses, common issues include morning grogginess and "hangover" feeling, vivid or unusual dreams, headaches, and mild nausea. Long-term high-dose use may downregulate your body's natural production, though research on this is still evolving.
Who Should Actually Take It
Melatonin is most effective for jet lag recovery, shift workers adjusting to new schedules, people with delayed sleep phase syndrome (natural night owls who need to sleep earlier), and older adults whose natural melatonin production has declined.
It's less effective for general insomnia caused by stress, poor sleep hygiene, or anxiety. Those problems need behavioral solutions, not hormonal ones.
Natural Alternatives
If you want to boost your body's own melatonin production, get bright light exposure in the morning, dim lights and avoid screens in the evening, eat foods containing tryptophan (turkey, eggs, nuts, seeds), maintain a consistent sleep schedule, and consider magnesium glycinate, which supports the melatonin production pathway.
The Bottom Line
Melatonin is a useful tool when used correctly: low dose, right timing, right condition. But it's not a substitute for good sleep habits. The foundation of great sleep is always behavior — what you do during the day, how you wind down at night, and whether you're tracking what works.
SleepBetter.ai helps you track what's working — supplements, habits, and everything in between. Available on iOS.