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How Long Does It Take for Melatonin to Work?

When people are looking for the best sleep supplement, they want something that is fast-acting and effective. Most people choose melatonin sleep supplements because numerous studies and testimonials state they’re safe and work very well. If you’re considering taking Melatonin for the first time, you also might be wondering how long it takes to start working. 

Let’s get into it! 

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When Will Melatonin Begin to Take Effect?

The answer to this question will vary for everyone. Generally, melatonin absorbs into the body quickly, but many other factors will determine how long it takes to kick in. For some people, they could start feeling the effects in as little as 20 minutes. For others, it could take as long as an hour. Melatonin levels peak within an hour for most individuals, making them start to feel drowsy. 

Taking larger doses will not make melatonin take effect quicker, and it’s not recommended to take too much in one sitting. Everyone metabolizes drugs differently, and the formation of melatonin supplements will also determine the time it takes to act on the body. A person’s particular sleep issues and sleep hygiene habits will also determine how well melatonin will work. 

How Long Does Melatonin Stay in the Body? 

Melatonin doesn’t stay in the body for too long since it has a half-life of about one to two hours. This describes how much time it takes for the body to metabolize half a dose of medication. Since it takes about four to five half-lives for the body to eliminate a drug, melatonin may stay in the body for four to ten hours. The exact amount will depend on the dosage and formulation of the supplement. 

Of course, certain external factors can determine exactly how long the melatonin supplement remains in your body and when it’ll begin to wear off. Some of these include the following: 


Older adults may have melatonin stay active for longer periods since metabolism slows as you age. When the rate at which your body can metabolize melatonin slows down, it’ll take longer for it to wear off. 

Weight and Body Composition 

People over 250 pounds may not feel any effects of melatonin if they take it in small doses. Other factors that can determine when you might experience melatonin’s effects include your height and body composition. 

Use of Other Medication 

Certain medications can change the way your body processes supplements, including melatonin. Some of these include blood thinners, immunosuppressants, and stimulants. These may also increase your risk of unwanted side effects. For this reason, it’s essential to talk to your doctor if you’re taking medications and you want to try a melatonin supplement.  

Caffeine Intake 

Caffeine may counter the effects of melatonin by modifying its production. Since it’s also a stimulant, it’ll disrupt your sleep-wake cycle. For best results, you should avoid caffeine intake after about 2 pm. 

Exposure to Bright Lights 

Poor sleep habits like exposure to bright, artificial light will tell the brain to stay awake longer. This exposure sends signals to your brain that it’s daytime and makes it harder for the melatonin to take effect. 

How Much Melatonin You Should Take 

There is no standard dosage of melatonin that fits everyone., so how much you should take will depend on each individual. It’s always best to start at the lowest dose and slowly work your way up until you start sleeping better. Taking the appropriate amount of melatonin can also reduce the severity of side effects. 

Below is a general idea of how much melatonin is ideal for each age group. 

Older Adults 

Because of what we previously mentioned about older adults’ slower metabolism, they may need lower doses of melatonin. A safe and effective one to start with is 0.1 milligrams about half an hour before bedtime. If you notice it not taking effect, gradually increase the dosage. 

Young Adults 

A safe dosage for adults is between 0.05 milligrams and 5 milligrams. Depending on your reason for taking melatonin, it could also vary. For example, those who want to avoid let lag generally need a lower dose of about 0.5 to 2 milligrams. You’ll want to avoid taking melatonin if you’re pregnant or breastfeeding. If you’re currently taking other medications, talk to your doctor first. 


Children should not take melatonin unless a doctor recommends it. Children can often experience short-term insomnia because of situations like starting a new school, an illness, or restless legs. 

Doctors may recommend melatonin for children who are sleeping poorly due to things like autism spectrum disorders and ADHD. Recommended doses will vary, and there are no standardized charts by age and weight for children or how often a child should take melatonin. 


Infants and babies under the age of three should not take melatonin at all. Their circadian systems are still developing at around three months old, and no long-term studies have been done on melatonin use in babies. It’s best to talk to a pediatrician if your infant is having trouble sleeping, and they can help develop a treatment plan and determine the possible causes. 

Are There any Side Effects? 

Melatonin carries the risk for some mild side effects, especially if you take too much of it. The FDA does not regulate it the same way they do with prescription drugs, so there aren’t any official guidelines for taking melatonin. It’s also a dietary supplement, so you must know the potential side effects that come from taking it. 

Some of the most common ones people notice include: 

  • Headaches 
  • Nausea 
  • Dizziness 
  • Drowsiness 

Some people can also experience less common side effects, particularly those who are sensitive to melatonin or are taking medications that could interfere with it.  Some of the more rare side effects of taking too much melatonin include the following: 

  • Anxiety and depression 
  • Tremors 
  • Joint pain 
  • Seizures 

When to Take Melatonin for the Best Results 

The best time to take a melatonin supplement is about an hour before bed. Your brain should naturally increase its melatonin production about one to two hours before you’re ready to sleep. However, taking the supplement can help make the process smoother, especially for those who don’t produce enough melatonin. 

Taking the best sleep supplement at bedtime has also been shown to improve sleep in children and those who are blind. It seems to reduce how much time is needed to fall asleep. 

when to take melatonin
Would You Like to Try Melatonin Gummy Bears for Better Sleep?

If you’re considering trying melatonin gummy bears for better sleep, we’d be happy to assist! Reposé’s Goodnight Melatonin Gummies are a delicious treat for falling asleep faster and staying asleep longer. Try one today and experience the feeling of a restful night of sleep.