Michele Ross is a freelance writer based in Los Angeles. She primarily covers beauty, wellness, nutrition, and culture, and her goal is to empower readers to make informed decisions about their routines. Both on and off the clock, she geeks out on skin care ingredient deep dives, astrology, and K-pop.

Anyone who’s ever tried to hack their way to better sleep has likely taken (or, at the very least, heard a thing or two about) melatonin supplements. Not only have they been around for decades, but they’re also surging in popularity. According to a 2022 study published in the Journal of the American Medical Association (JAMA), usage among adults in the United States has more than quintupled between 1999 and 2018. It’s no surprise that they’re among the most popular supplements for sleep as they improve sleep latency — i.e., the time between your head hitting the pillow to when you drift off into dreamland — as well as boost sleep quality. But is there a sweet spot for when you should take melatonin?

Keep reading to discover how long melatonin takes to work, the factors the timing hinges upon, and how long it lasts in your system. Plus, key insights worth knowing to help you prevent melatonin from making you groggy the next day.

How Fast Does Melatonin Take to Work On Average?

Supplemental melatonin takes about 1 to 2 hours to reach peak levels in your system. However, you may start to feel its initial effects within 20 to 30 minutes after taking a melatonin supplement.

It’s worth remembering that melatonin is a hormone that naturally occurs in the human body. Produced by the pineal gland, melatonin regulates circadian rhythm (aka sleep-wake cycles) and signals to your brain that bedtime is near. Natural melatonin production tapers off in the daylight hours and kicks back into gear by nightfall — yet it can also get thrown off balance due to artificial sources of light such as lamps, televisions, and smartphones. As such, you can practice healthy sleep habits and promote normal levels of natural melatonin by dimming lights, drawing the curtains closed, and avoiding screens during your wind-down time for bed.

In case you struggle with sleep problems, oral melatonin is a common remedy to help catch shut-eye… and pretty fast, at that. Per a 2013 meta-analysis published in the journal PLoS One, 19 studies involving nearly 1,700 adults and children with sleep disorders found that melatonin supplementation:

  • Improved sleep latency (the time it takes to fall asleep) by 7 minutes
  • Increased total sleep time by 8 minutes
  • Significantly improved sleep quality compared to placebo groups

While these numbers on melatonin use might not seem like they’d move the needle too much, note that they’re averages amongst a large sample size. Plus, even these seemingly small nightly wins can lead to major gains — in the form of more energy, alertness, and overall well-being — when sustained over time. Plus, anyone who’s ever experienced a sleep deficit or sleep problems will know how much even one solid night of restful sleep can change the game upon waking.

Factors That Can Affect How Long Melatonin Takes

Another important FYI about supplementing with the famed sleep hormone: Instead of functioning as a sedative, melatonin is more akin to a lullaby, easing you to sleep. But in order for it to kick in when you want it to — that is, soon after you tuck yourself into bed — you’ll want to get the timing right.

Here are a few different factors that will impact how fast Melatonin settles into your system for a peak snooze.


The dosages investigated in Melatonin studies vary widely, with 0.1 mg and 10 mg on the tail ends of the spectrum. So, how much Melatonin should you take then? Naturally, the more melatonin you take, the more pronounced its potency will be. This could mean that a higher dosage of Melatonin can cause you to knock out like a light quickly… but it will likely lead to higher chances of experiencing undesired side effects — like the dreaded melatonin hangover.

Melatonin supplements offering 1 or more mg can flood brain receptors and circulate as much as 100x more of the sleep hormone in your blood, leading to a gnarly hangover. Instead of overtaxing your system, feeling out of sorts upon waking, and getting more Melatonin than you really need, experts advise taking as low of a dose as possible. This rings true especially if you’re just starting out with melatonin supplementation, as it can help reduce other side effects such as:

  • Headache
  • Stomach ache
  • Dizziness
  • Nausea
  • Dry mouth
  • Strange dreams

Remember: The trick is to encourage sleepiness, not flat-out sedation. Instead of taking Melatonin every night, consider only taking it for travel, shift work, and nights you have trouble falling asleep.

Individual Metabolism

How long melatonin takes to work will also hinge upon your own metabolism. As is the case with many exogenous substances, contributing factors such as your gender, age, weight, health status, and medications you take can impact how rapidly or strongly you will feel its effects.

Your natural melatonin levels will also hinge upon these influences. For instance, as the Cleveland Clinic explains, melatonin levels:

  • Peak in children before puberty and level out in their late teens
  • Are higher in adult women than men
  • Remain stable post-puberty until age 40, which then decline over time

With these points considered, a woman may find that melatonin supplements don’t work as quickly at the age of 50 as they did in decades past. Moreover, her husband or her mother may find that the same supplement takes a bit longer to help them doze off at night.

Form of Melatonin

There are different forms of supplemental melatonin to choose from, which may also influence how long it takes for the sleep supplement to work. The various types of oral melatonin include:

  • Powders
  • Capsules
  • Tablets
  • Liquids
  • Gummies
  • Extended-release pills

Moreover, there are different sources of melatonin available on the market:

  • Plant-based
  • Animal-based
  • Synthetic

Most melatonin supplements are made with synthetic ingredients and sometimes from animal sources. Safe and effective as they are, plant-based forms of melatonin tend to be less commonly used. However, they’re worth scoping out if you stick to a plant-based diet and/or prefer holistic ingredients whenever possible.

Some melatonin supplements include other nutrients that have proven benefits for better sleep, which can also impact the time they take to work. For instance, Moon Juice’s own all-natural sleep-supporting Melatonin powder — which includes Phytomelatonin, a plant-based form of the sleep aid extracted from organic Alfalfa and Chlorella — also stars:

  • Chelated Magnesium Bisglycinate and Gluconate to calm your mind and body before bed
  • L-Theanine, which promotes relaxation and sleep quality through anxiolysis (i.e., unstressing rather than sedating)

Sleepy Magnesi-Om® includes 0.3 mg of Phytomelatonin alongside these two calming, sleep-friendly aids. Simply put, the melatonin dosage is just enough to keep your natural levels in the ideal range to support a normal sleep cycle — all the while keeping stressors and sleepless nights at bay and avoiding next-day grogginess.

Bonus: This melatonin and magnesium powder for sleep comes in a delicious, blackberry-flavored powder with zero sugar, making it a perfect bedtime tonic for occasional restlessness. Simply mix 1 stick into 12 oz of water. Sip and enjoy an hour or 2 before bedtime (adjusting as needed based on your own trends around timing and tolerance).

Time of Intake

To stay on track with healthy human sleep-wake cycles, you’ll wake up close to when the sun rises and catch your ZZZ’s past sunset. However, these snooze cycles aren’t always possible or plausible to stick to — not only if you have a history of sleep disturbances but also if you work irregular night shift work or experience jet lag by crossing time zones.

Even if you supplement with melatonin, you may find that it takes longer to fall asleep in the daylight hours. That’s because your naturally occurring levels of melatonin will be lower, while wakeful hormones such as cortisol will be higher. At any rate, while it may take a bit longer to drift off into dreamland if sunlight is peeking through your curtains, melatonin supplements are still helpful, effective, and often recommended to encourage restful sleep in individuals under these circumstances.

For instance, research shows that:

  • Travelers crossing time zones can reduce jet lag by taking melatonin an hour before the desired bedtime of the arrival destination (whether on the day of travel or up to 3 days before flying, the latter if crossing 7 or 8 time zones) and continuing for up to 3 days thereafter.
  • Overnight shift workers can experience improvements in their sleep cycle by taking melatonin 30 minutes before daytime sleep.

Again, people who adhere to “normal” hours and schedules are best served taking Melatonin 1 to 2 hours before their desired bedtime, modifying based on personal factors and tolerance. Some people may find that they start to feel snoozy only 20 or so minutes post-supplementation, so take care to observe, honor, and abide by those cues on an individualized basis. Plus, you’ll be all the wiser to support your natural Melatonin production by easing your way into a calming bedtime routine, which includes dimming bright lights and avoiding stimulating activities.

Cellular Waters

How Long Does Melatonin Last?

Unlike many other supplements that require time and consistency to be effective, Melatonin kicks into gear and leaves your system pretty rapidly. Per a 2017 review in the journal Current Neuropharmacology, oral melatonin supplements are quickly metabolized. Depending on the dosage, formulation, and the individual factors related to the person taking them, Melatonin supplements will have a half-life of around 20 to 40 minutes and will last in a person’s system for 4 to 8 hours.

In short, melatonin supplements work on a kind of one-and-done basis. They signal to your body it’s time to snooze and help you drift off into restful sleep, and are typically metabolized after a full night’s rest (i.e., around 7 to 9 hours for adults). A higher dosage may cause it to last longer in your system, which can contribute to that dreaded day-after hangover. Taking Melatonin only at or after your desired bedtime can also adversely affect your sleep timing and sleep quality, causing you to feel groggy and foggy once your alarm goes off come a.m. and well into the daytime.

All things considered, try to take a low dose of Melatonin no more than 2 hours before bedtime to support — not surpass — your natural levels of the sleep hormone. By microdosing as needed with plant-based sources such as that found in Sleepy Magnesi-Om®, you can help normalize your circadian rhythm to keep your sleep schedule on track, your daytime energy and alertness in swing, and grogginess on the back burner.