How Long Does Melatonin Stay in Your System?

Melatonin supplements are becoming increasingly popular as a sleep aid. Research has shown melatonin promotes sleep and helps regulate our circadian rhythm - something we all need when living in an artificially lit world! [4] Your brain produces melatonin each night as darkness falls, but light pollution can reduce it. [5]

Melatonin is absorbed and excreted fairly quickly. The half-life (the time it takes to eliminate half the dose of a drug) of melatonin is about 30 to 50 minutes, and it takes 4 to 5 half-lives to eliminate the supplement. This means melatonin can stay in our system for around 4 to 5 hours. [1, 6]

Let’s explore how melatonin works and how best to take it to optimize our sleeping patterns.

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How Does Melatonin Work?

You know that sleepy feeling you get when you climb into bed every evening? That’s caused by your melatonin levels rising, signalling to your body that it’s time for sleep.

Melatonin is a naturally occurring hormone; the brain produces melatonin in the pineal gland. It helps regulate our sleep-wake cycle, otherwise known as our circadian rhythm.

Melatonin is regulated by light, so when we are exposed to light in the daytime, our melatonin is suppressed, so we feel active and alert.

However, as the lights dim in the late afternoon and evening, our melatonin increases, which is what causes us to feel sleepy.

These days we typically reside in environments that don’t cater well for our natural melatonin production. Artificial light, work stress, sleep disorders, and general life can often get in the way of achieving a natural, good quality sleep, especially for those with sleep issues.

This is why supplementation is recommended, and may be of particular interest to those who wish to avoid prescription medications or prescription sleeping pills. Or those who may have trouble sleeping due to circadian rhythm disorders, including:

• Frequent travellers (in relation to jet lag)
• Shift workers

Though melatonin doesn’t just help us sleep better!

Other effects of melatonin include:

• Neuroprotection [7]
• May have a supportive role in cancer treatment [8]
• Eye health [9]
• Helping with symptoms of tinnitus [10]
• Improving mood [2]

Best Time to Take Melatonin Supplements

The best time to take melatonin would depend on the supplement, especially as some supplements are formulated to extend the release to mimic the effects of natural melatonin production.

However, it’s generally recommended to take melatonin 30-60 minutes prior to your desired bedtime. [3]

We recommend taking Performance Lab Sleep 30-minutes before bedtime for the best results!

Immediate vs. Extended-Release Melatonin: What’s the Difference?

Immediate-release melatonin provides a rapid surge of melatonin, and may be ideal if you have trouble falling asleep and want to fall asleep faster.

Extended-release, on the other hand, takes longer to start working, but it's intended to maintain stable melatonin levels in the blood for longer, possibly making it better suited for those waking up throughout the night and needing longer support for staying asleep.

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A case in point: a 2024 randomized, double-blind crossover trial in healthy adults compared 4 mg immediate-release (IR) and 4 mg extended-release (ER) melatonin. Same people, separate nights. Blood levels tracked for 10 hours.

Here's what they found [3]:

• Slower and steadier release: ER melatonin peaked about 1.6 hours after ingestion, whereas IR melatonin levels peaked after just 0.6 hours.
• Longer half-life: ER's elimination half-life averaged 1.63 hours, compared 0.95 hours for IR.
• Smoother curve: Peak concentration was lower for ER (about 7,600 pg per mL) than IR ( about 13,100 pg per mL), but ER kept levels above 300 pg per mL for roughly 6 hours and didn’t drop below 50 pg/mL until around 9 hours after the dose.

Simply put, immediate-release melatonin may raise melatonin blood levels higher at first, but its effects may also last shorter.

In the light of this article, this means that immediate-release melatonin may get out of your system sooner than its extended-release counterpart.

How Much Melatonin to Take? Dosage and Side Effects

How much melatonin is right for you depends on your tolerance, but starting with a low melatonin dose - around 0.5mg - is often reported as a good starting point. Though, up to 3-5mg is thought to be an effective dose with no adverse effects the following day.

Taking more will not necessarily lead to better sleep. It can, in fact, have negative side effects - such as feeling drowsy and experiencing daytime sleepiness, headaches, and nausea. [11]

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Always check with a doctor if you have high blood pressure, are starting a new medication, taking blood thinners, or have other ongoing health issues before considering any supplement, including melatonin.

Avoid taking melatonin and drinking alcohol, as this can intensify drowsiness and lead to other side effects.

How Long Melatonin Remains in Your System

Typically, melatonin remains in our system for around four to five hours, but depending on the formulation, it can be longer. Other supplements or certain medications can extend this.

However, the total time it takes for any supplement or medication to clear will differ from person to person, melatonin included. This is the reason it’s important to determine a dose that works for you, and experiment with your ideal timing.

The following factors influence how long melatonin stays in your system:

• Age
• Caffeine intake
• Body weight
• Other medications
• Whether you smoke tobacco
• How often you take melatonin
• Overall health status

Older people tend to process melatonin more slowly, so its effects, including the next-day drowsiness, can last longer. [12, 13, 14]

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Smart Habits to Help You Fall Asleep and Avoid Next-Morning Grogginess

One tip with melatonin is to keep a low dose (0.5-3mg). Taking high doses of melatonin, like in the study we've seen earlier, can take longer for your body to process. By the time you wake up, some of the melatonin's effects may still linger.

Other factors to consider is sticking to a consistent bedtime and avoiding caffeine late in the day.

If you like a clean, science-backed formula, Performance Lab® Sleep combines natural melatonin from tart cherry with relaxing nutrients like magnesium and L-theanine. It's designed to support a smoother night’s rest without next-day grogginess.

Summary

Melatonin is a naturally occurring hormone that helps us regulate our sleep-wake cycle, or our circadian rhythm. Supplementation is sometimes recommended, particularly for those who are frequent travellers or shift workers.

It’s generally recommended to take melatonin 30-60 minutes before bedtime, starting with a low dose to determine your tolerance. Doses of up to 3-5mg are shown to be effective with minimal side effects.

Melatonin typically stays in our system for around 4-5 hours, though this depends on several factors such as weight, age, and health status. Avoid driving or using heavy machinery within 5 hours of taking it.

More melatonin does not equal better results, so avoid over-serving or supplementing throughout the daytime, which could further hinder your sleep schedule!

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Further Reading: Is Melatonin Addictive? What You Need to Know

Melatonin FAQs

• Will Melatonin Show Up on a Drug Test?

Melatonin isn't a controlled substance. As such, it won't show up on standard tests in employment and athletic drug screenings.

• Does melatonin make you drowsy the next day?

Depending on your dose of melatonin, it might feel difficult to wake up and get going the next day. Stick to doses of less than 1 mg if you want to avoid grogginess after waking up. Instead of synthetic melatonin, try a natural sleep supplement like Performance Lab® Sleep which contains Montmorency tart cherry as a low-dose, natural source of melatonin.

• How late is too late for melatonin?

If it's less than 5 hours before you plan to wake up, it's best to skip melatonin. It can still linger in the body around that mark, and well after in the case of the extended release counterpart.

• Can I take melatonin if I have to wake up in 4 hours?

It's not ideal. You might feel groggy from the melatonin that is still circulating in your system. It should especially be avoided if planning to operate machinery.

• What does melatonin do to your brain?

It binds to melatonin receptors in the brain’s suprachiasmatic nucleus, which is essentially your internal clock, helping to regulate sleep and wake cycles. Melatonin is also one of your most powerful antioxidants, protecting brain cells, mitochondria, and DNA from oxidative stress.

• What does a melatonin hangover feel like?

A melatonin hangover feels like sleepiness, mild headache, or dizziness the next morning. It usually happens when you take too much or too late. It's not dangerous by itself, but it's best not to drive a car or operate a machinery in this state.

• Does melatonin help ADHD?

Melatonin is not a treatment for ADHD itself, but it may support bedtime routines and sleep quality in children and adults with ADHD, including when insomnia is a problem.

• Can a blood test check melatonin levels?

Yes, a lab test can easily detect melatonin in blood, as well as in urine and saliva.