Melatonin is not a sedative or a sleeping pill. It’s a naturally occurring hormone produced by your body that regulates your circadian rhythm by sending a signal that it’s time for sleep. Its levels are low during the day, then they rise at night, peak during sleep, and drop just before you wake up.
Because melatonin helps manage sleep/wake rhythms, taking a supplement can help people who struggle to get to sleep earlier or more easily. That said, the timing and dose of a melatonin supplement can be tricky to get right. “A lot of people might be taking melatonin a little too late and too high of a dose,” said Michael Grandner, PhD, director of the Sleep and Health Research Program at the University of Arizona, during his 2025 Embody webinar, “How Better Sleep Promotes Mental, Metabolic, and Cardiovascular Health.”
Because many people mistakenly think of melatonin as a sleep aid, they assume they should wait until bedtime to take the supplement. In fact, this timing doesn’t work well for most people. Melatonin is not “rapid release.” After taking a supplement, it takes 30 to 60 minutes for your body to receive the “nighttime is here” signal and start to shift into wind-down mode.
Because of this, melatonin doesn’t work well to help you fall back asleep if you wake in the middle of the night. At that point, your system already has all the melatonin it needs. If you’re awake, it’s likely for another reason, such as sleep apnea, rather than a problem with your circadian rhythm.
If you take melatonin in the middle of the day, hoping it’ll help you with a nap, it won’t be effective. At this time, your body isn’t producing melatonin on its own, so the supplement won’t bolster your body’s natural effect.
There’s really only one window of time when it’s effective to take melatonin, and that’s roughly an hour before bedtime. If you take melatonin 30 to 60 minutes before you hope to turn in, it can augment your body’s naturally occurring melatonin levels, causing them to rise faster, or start rising a little earlier so that you become ready for sleep more quickly. If you think of your sleepiness as a ball rolling downhill, taking melatonin an hour before bedtime just helps the ball pick up momentum, giving it a bit of a push.
Research has found that melatonin tends to be effective at very low doses, with 1 milligram usually being sufficient. While you will find it sold in 2, 3, or 5 mg capsules, there is no need to use dosing this high. Higher doses are not more effective and may cause you to feel groggy in the morning.
