If you’re thinking about taking melatonin to help you sleep, you probably have a few questions. How does it work? When should I take it? How long will it last in my system?
Perhaps you’re wondering so that you can plan a time to take it at night without waking up groggy in the morning. You might also want to know how long it lasts in case you’re taking it for the first time and are worried you won’t like how it makes you feel.
In either case, melatonin absorbs relatively quickly and leaves the body quickly as well. In this article, we’ll get into just how long melatonin takes to absorb and how long it lasts in the body, depending on the type of melatonin.
Learn more: Read our complete guide on melatonin.
How Quickly Does the Body Absorb Melatonin?
The rate at which the body absorbs melatonin How quickly melatonin will depend on the type of melatonin you’re taking, along with your unique metabolism. Most people will take melatonin orally as a tablet, capsule, or gummy.
If you’re taking standard, fast-release oral melatonin, your melatonin levels will peak about an hour after administration1. At this point, the amount of melatonin will be between 10 and 100 times higher than your body’s natural melatonin levels.1
Oral melatonin is metabolized in the liver and its half-life is only about 40 minutes2. The term “half-life3” refers to how long it takes for half of the active substance to be eliminated from the body. Typically, it takes about 5.5 half-lives4 for most drugs to be removed fully from the body and no longer have any clinical effect. Therefore, melatonin will likely go through 5.5 more 40-minute half-life cycles throughout the night.
The melatonin should be completely out of your system between four and eight hours after ingestion.1
Explore our expert-selected picks for the Best Melatonin Supplements.
Fast-Release Melatonin vs. Extended-Release Melatonin
Unless a melatonin supplement is labeled as extended- or prolonged-release, it is likely going to be a fast-release supplement. A fast-release product means that all of the medication5 is released at once, rather than gradually throughout the night. These are absorbed and cleared from the body more rapidly than extended-release melatonin.5
Extended-release pills, on the other hand, “better mimic the naturally occurring melatonin” in the body because they release more slowly through the night. Additionally, extended-release melatonin takes longer to reach its peak concentration (about 1.56 hours) and takes longer to eliminate, with a half-life of 1.63 hours.5
The maximum concentration of extended-release melatonin is lower than that of immediate-release melatonin; however, extended-release pills seem to keep melatonin levels elevated for longer (about six hours) before they even begin to dip. Melatonin levels should return to baseline within nine hours after taking extended-release melatonin.5
This means that while fast-release melatonin should help you fall asleep, extended-release melatonin may be better at helping you stay asleep through the night. It also means you may want to take fast-release melatonin about one hour before bedtime and extended-release about an hour and a half or two hours before bedtime.
Does Melatonin Make It Hard to Wake Up?
Melatonin shouldn’t make it hard to wake up. As mentioned, it is eliminated from the blood while you’re sleeping, so somewhere between four and nine hours after you’ve taken the melatonin, it should no longer affect you.1,5
That said, some people may experience morning grogginess6 with melatonin. If this happens to you, it may mean that you’re taking it too late at night, taking too high a dose, or taking a supplement that isn’t high quality and may contain ingredients not listed on the label.
To avoid morning grogginess, make sure you’re taking melatonin at least one or two hours7 before your intended bedtime (never right before bed) and that you’re buying supplements that are USP-verified8. A USP verification means your melatonin supplements have been third-party tested and include the exact ingredients listed on the label. Supplements that are not third-party tested in this way have no such guarantee.
Keep in mind that with melatonin supplements, less is usually more. Experts recommend sticking with a dose somewhere between 1 and 3 milligrams9, with a maximum recommendation of 5 milligrams.2
Types of Melatonin
Pills can be either tablets or capsules10 and can either come in immediate-release formulas or extended-release formulas. Any oral pills will pass through the digestive system11 and are then processed in the liver. This means that some of the melatonin in the pill will be lost along the way before getting into your bloodstream.11
Gummies are sweet, soft chewables that can be a good fit for children taking melatonin or adults who prefer not to take melatonin in pill form. Like pills, melatonin gummies will pass through the digestive system and liver.11
Liquid melatonin can be a good option for those who don’t like pills or want more freedom to specify their dose. You can take liquid melatonin by dropping it into your mouth with a dropper. This form of melatonin also passes through the digestive system and liver12 since it is taken orally, and the difference in absorption rates between liquids, capsules, and tablets seems to be marginal.
Melts are dissolvable tablets that you can place either on your tongue, under your tongue, or between your gum and cheek. According to research, melatonin melts that are absorbed by the mucus membrane (also known as “oral transmucosal”) have been shown to put more melatonin into the bloodstream13 when compared to oral melatonin. It is unclear if this means it will also be eliminated from the body faster.
“Transdermal patches” are adhesive strips placed on the skin to deliver a medication. Research shows that melatonin transdermal patches tend to release the melatonin more slowly and steadily through the night, sort of like an extended-release pill might.13 These patches seem to be particularly effective14 for shift workers who need to sleep during the day, those with jet lag, and elderly people who wake up very early in the morning.
Nasal sprays may be a good option for people who dislike taking pills or who want a faster-acting, more bioavailable form of melatonin.13 Since these sprays are delivered straight into the nose, they bypass the digestive tract and begin working more quickly. Research shows that of the various forms of melatonin, nasal sprays are absorbed the fastest and have the highest bioavailability – meaning, more of the melatonin actually makes it into your system.13
Frequently Asked Questions
How long does it take for melatonin to leave your body?
If you’ve taken an immediate-release pill, it should fully leave your system within four to eight hours.1 If you’ve taken an extended-release pill, the melatonin should leave your body within about nine hours.5 These numbers will vary depending on the type and dosage of melatonin you’re taking, as well as your own unique metabolism.
Can melatonin make you tired the next day?
Most people will not experience any side effects with melatonin, however, of the side effects reported, next-day sleepiness is among the most common.6 This may be because your dose is too high, you’re taking it too late, or your melatonin product is not the best quality and contains ingredients not listed on the label.
To avoid next-day tiredness with melatonin, be sure you’re taking it one to two hours before bedtime, sticking to a low dose (between 1 and 3 milligrams), and buying a product that is marked “USP-verified.” 7, 8, 9
How late is too late for melatonin?
This really depends on when you want to go to sleep. If your desired bedtime is 10:00 p.m., you should take melatonin between 8:00 and 9:00 p.m. since these supplements take between one and two hours to work.7
You also want to keep in mind how long melatonin stays in the system. Let’s say you took melatonin at 1:00 a.m. It wouldn’t take effect for another hour or two, and then it would stay in the system for four to nine more hours.1, 5 This could certainly make you feel sleepy the next day and could inadvertently shift your circadian rhythm later.
Because of this, it may be best to work backward. For example, if you want to wake up by 7 a.m. feeling alert and well-rested, you should count backward about 10 hours and this is when you should take melatonin. This way you’ll allow one or two hours for the melatonin to start working, enough time to get eight hours of sleep, and then wake up with no melatonin left in your system.
Natalie is a content writer for Sleep Advisor with a deep passion for all things health and a fascination with the mysterious activity that is sleep. Outside of writing about sleep, she is a bestselling author, improviser, and creative writing teacher based out of Austin.
- Tordjman, Sylvie., et. al. “Melatonin: Pharmacology, Functions and Therapeutic Benefits”. Current Neuropharmacology. 2017.
- Arendt PhD, Josephine., Aunlinas MD PhD, Anna. “Physiology of the Pineal Gland and Melatonin”. Endotext. Last modified October 30, 2022.
- “Psychiatric medication”. Mind.org. 2021.
- “What do you mean by the half life of a drug?”. Drugs.com. Last modified May 30, 2022.
- Mun, Jonathan G., et al. “A Randomized, Double-Blind, Crossover Study to Investigate the Pharmacokinetics of Extended-Release Melatonin Compared to Immediate-Release Melatonin in Healthy Adults”. Journal of dietary supplements. 2023.
- “Side effects of melatonin”. National Health Service. Last modified February 13, 2023.
- “Common questions about melatonin”. National Health Service. Last modified February 13, 2023.
- “USP Verified Mark”. USP.org. Webpage accessed January 23, 2024.
- “Melatonin for Sleep: Does It Work?”. Johns Hopkins Medicine. Webpage accessed January 23, 2024.
- Orrange, Sharon. “Capsule or Tablet? Pros, Cons, and Prices Explained”. GoodRx Health. Last modified February 23, 2022.
- “First Pass Effect”. Study.com. Webpage accessed January 23, 2024.
- Jones, Erin., Lewis, Brandon., Chamberlin, Mauricio. “No, liquid medication is not more effective than capsules”. WCNC Charlotte. 2023.
- Zetner, D., et. al. “Pharmacokinetics of Alternative Administration Routes of Melatonin: A Systematic Review”. Drug Research. 2015.
- Aeschbach, D., et al. “Use of transdermal melatonin delivery to improve sleep maintenance during daytime”. Clinical Pharmacology & Therapeutics. 2009.