How long does melatonin last?
Based on the above, the key melatonin’s effectiveness is to take your sleep supplement at the right time of day. Take melatonin too early, and the effects may be canceled out by a bright and stimulating environment. Take a supplement too late, and the melatonin won’t have time to induce that important period of calm before you try to sleep.
According to Johns Hopkins Medicine, melatonin levels begin to rise around two hours before the body anticipates bedtime. So, the general recommendation is to take between 0.5 and 5 milligrams of melatonin two to three hours before your ideal bedtime. Remember, your circadian rhythm responds to habit-forming behaviors, meaning that melatonin doesn’t always work on the first occasion. To ease jet lag, for example, it may be necessary to begin taking melatonin supplements starting a few days before your trip—working out when your new bedtime will be and counting back two hours from there.
As long as your sleeping environment remains conducive to sleep, you can expect melatonin to remain in your body throughout the night. According to Cleveland Clinic, there is a minor body of evidence to suggest that melatonin can help restless sleepers to stay asleep, but the general consensus is that melatonin does not remain in the body past one sleep-wake cycle.
How long does it take for melatonin to wear off?
Just as with naturally occurring melatonin, light, activity, and the daylight stages of your circadian rhythm will deplete the presence of melatonin in your body. The rate of that depletion depends on several factors, such as: