How Long Does Melatonin Last for Sleep?

June 24, 2021 | Casper Editorial Team

Disclaimer: This article is for informational purposes only and should not be taken as medical advice.

We’ve all had restless nights. Whether tossing and turning is a nightly occurrence or this is the first time you’re up counting sheep, you’ve likely heard of the popular sleep aid melatonin. But what is melatonin, and how long does melatonin last for sleep?

Melatonin is a naturally occurring hormone that can help promote sleepiness, so you fall asleep fast. Many people have turned to melatonin supplements, which are available over the counter, to help them catch some zzz’s in a pinch.

Before using melatonin, it’s essential to understand the potential impacts it can have on your health. Keep reading to learn everything you need to know about using melatonin for sleep.

What Is Melatonin?

Melatonin is a hormone that promotes sleepiness by regulating your circadian rhythm. Melatonin can help regulate your sleep cycle and can be used as a sleep aid for conditions like insomnia. Some everyday situations where people commonly use melatonin include:

  • Recovering from jet lag
  • Migraines
  • Insomnia
  • Side effects of stimulant medications like Adderall 
  • Symptoms of neurodevelopmental disorders like Autism Spectrum Disorder
  • Irritable bowel syndrome

But how does melatonin affect your body? According to Johns Hopkins sleep expert Luis F. Buenaver, Ph.D., C.B.S.M, melatonin levels rise in the evening to put you in a state of quiet wakefulness that helps promote sleep. Your body naturally produces melatonin, and taking melatonin in the evenings can help supplement your natural melatonin production to get the rest you need.

How Does Melatonin Work?

Melatonin is produced by the pineal gland of the brain, which transforms serotonin into melatonin when your internal clock sends it the right signal. High melatonin levels cause your blood pressure and body temperature to lower, putting you in the mood for sleep. Additionally, if your body senses that it’s nighttime and your eyes absorb less light, your body will know to switch from serotonin production to melatonin production. 

This is one reason why turning down the lights and practicing proper sleep hygiene before bed is so important. If you keep the lights on, your body may have a harder time producing melatonin, meaning that you’re not as prepared for sleep. 

How Long Does It Take For Melatonin To Work?

Melatonin supplements typically begin to kick in between 20 minutes and two hours after ingestion, which is why Buenaver suggests taking one to three milligrams two hours before bedtime

Additionally, natural melatonin levels rise around two hours before bed, so having a consistent bedtime routine can help signal to your body that it’s time to ramp up melatonin production. 

Melatonin can affect everyone differently, meaning there’s no single right answer to how long melatonin lasts. You may need to do some trial and error to figure out when to take melatonin before bed and how much to take so you can stay asleep. 

Regular vs. Extended Release

When you think of melatonin, you’re likely thinking of a regular pill that instantly releases melatonin into your body. However, extended-release melatonin pills, sometimes called slow- or time-release pills, allow the melatonin to dissolve in your body gradually. 

Extended-release melatonin mimics natural melatonin production in your body, and for people who wake up throughout the night, it’s particularly helpful in keeping you asleep and helping you fall back asleep

How Long Does Melatonin Stay in Your System?

The regular melatonin half-life, or the time it takes for your body to reduce the melatonin by half, is around 40 minutes. This means half of the melatonin is processed in the first 40 minutes, and the other half is processed throughout the rest of the night. 

Factors Affecting How Long Melatonin Lasts

But how long does melatonin last in your system? Melatonin typically stays in your system for around four to eight hours, but this range largely depends on external factors, including:

  • Age: Your metabolism slows as you age, meaning the rate at which your body can metabolize the melatonin also slows. The older you are, the longer it may take for melatonin to wear off. 
  • Caffeine: Research has shown that caffeine can modify melatonin production to counteract the effectiveness of the supplement. 
  • Light exposure: Exposure to bright light, especially the blue light emitted from technology, can send signals to your brain that it’s daytime, making it harder for the melatonin to take effect. 
  • Body size: Factors like your height and weight impact how you absorb melatonin and how it affects you. 
  • Tobacco use: In animal studies, nicotine has been shown to inhibit melatonin’s effectiveness in the body. 
  • Other medications: Additional medications like blood thinners, immunosuppressants, and stimulants may counteract the effectiveness of melatonin. 

How Long Does It Take for Melatonin to Wear Off?

Melatonin takes between four to eight hours to wear off, but the amount of melatonin you take can cause this number to vary significantly. Generally, Buenaver suggests taking the lowest dose possible and advises starting at around one to three milligrams. 

At a lower dosage, the melatonin will wear off quicker, and you’ll be less likely to experience any side effects.

What Are the Side Effects of Melatonin?

Since melatonin is a dietary supplement, it’s important to understand the potential side effects. The Food and Drug Administration (FDA) doesn’t regulate melatonin the same way they regulate prescriptions, which means that there aren’t any official guidelines for taking melatonin. 

The most common melatonin side effects include:

  • Headaches
  • Nausea
  • Drowsiness
  • Dizziness

Other less common side effects can include:

  • Anxiety or depression
  • Irritability
  • Confusion
  • Tremors
  • Sleep loss
  • Joint pain
  • Abdominal pain
  • Seizures

If you’re thinking about using melatonin for sleep, talk to your doctor beforehand to make sure that melatonin is the right sleep aid for you.


Before taking melatonin, it’s crucial to understand how it’ll impact your body and learn to figure out the correct dosage for you. 

Will 5mg of Melatonin Put Me To Sleep?

Different people react differently to melatonin, but it’s important to note that melatonin doesn’t dose like a drug. A higher dose is not necessarily better, and might lead to more side effects. You’ll want to start at a low dosage of around 1 to 3 mg of melatonin until you find the proper dosage for you. 

How Long Does It Take For 5mg Melatonin to Kick In?

A typical melatonin dose is up to 5 mg and can take up to two hours to kick in. However, some people report melatonin working in as little as 20 minutes, which is why you’ll want to get your bedtime routine started when you take your melatonin. 

Is 10mg of Melatonin Too Much?

The Cleveland Clinic recommends doses of melatonin from 0.5 to 3 mg as an adequate amount to promote sleep or treat jet lag. However, melatonin is sold in doses of 1 to 10 mg, so you may want to consider splitting your pills to start with a smaller dose. The effectiveness of melatonin depends on timing more than dose, so if a lower dose like 5 mg doesn’t work, there’s little reason to feel that 10 mg will provide stronger effects. 

Does Melatonin Make It Hard to Wake Up?

Drowsiness is reported as one of the most common side effects of melatonin. If you feel like it’s more challenging to wake up after taking melatonin, you might want to practice natural ways to make it easier to wake yourself up, like exposing yourself to bright light or making your bed in the morning. 

Will Taking Melatonin Cause My Body to Stop Producing It?

While some medical practitioners have expressed concern that supplements may reduce the natural production of melatonin, research has not shown that taking melatonin will cause your body to stop naturally producing it.

How Long Is It Safe to Take Melatonin for Sleep?

Melatonin is safe to take nightly for one to two months if you feel it’s helping you sleep. However, Buenaver suggests stopping use if you aren’t feeling the benefits after a week or two.

Melatonin is a popular sleep aid that can be very helpful if taken correctly. While restless nights once in a while are normal, consistently failing to fall asleep may be a sign of a bigger problem. You may want to look into how long melatonin lasts to help you catch some zzz’s. 

Struggling to fall asleep can also be the product of a bad sleep environment. If you’re up counting sheep, you might want to consider a new pillow or mattress to set yourself up for success with the right sleep environment for a restful night.

Disclaimer: This article is for informational purposes only and should not be taken as medical advice.