How Long Does Melatonin Last?

Melatonin is a hormone that is naturally produced by our body when exposed to darkness. When you’re exposed to sunlight during the day, the melatonin levels in your body stay low, keeping you awake and alert. When you start to feel sleepy and tired, that’s due to your melatonin levels rising. 

This hormone controls your circadian rhythm, also known as your sleep-wake cycle. For this reason, many people who suffer from insomnia and other sleep disorders take melatonin supplements to help them sleep. 

Melatonin may be helpful for people who work at night, people affected by jet lag, blind people with dementia, people who take certain medications, and some children with neurodevelopmental issues.

In the United States, melatonin is widely available as an over-the-counter (OTC) medication, meaning you don’t need a prescription to buy it. You can likely find it at your local drug store or supermarket. 

If you have trouble sleeping, you’ve probably taken melatonin before, or at least heard of it. However, most people don’t even know how it really functions. 

If you fall into that category, don’t worry! Shop Hope has you covered. Here is our informative guide, explaining all the ins-and-outs of melatonin, from how long it lasts to when you should take it. 

How It Functions

The most important concept to grasp is how melatonin actually functions. Most people know that melatonin makes you sleepy. But how does it actually work? 

Melatonin is produced in the middle of your brain, by the pineal gland. This gland is controlled by the suprachiasmatic nucleus (SCN), a group of neurons or nerve cells located in your hypothalamus. The nerves in the SCN help control the body’s energy levels by sending signals to each other.

When exposed to sunlight in the day, light is absorbed through the retina in the eye and is sent to the SCN. As a result, the SCN works with the pineal gland to stop producing melatonin. Without this process occuring in our brains every day, it would be impossible for us to stay awake. 

This process is essentially reversed during the nighttime. When exposed to darkness, the SCN tells the pineal gland to release melatonin, which causes us to feel sleepy. 

During this process, your body temperature and blood pressure drop, which prepares your body for rest. Melatonin also causes neuronal firing to slow down, which is the reason why we have trouble focusing when tired. 

Melatonin supplements can change the way your body processes natural melatonin and interact negatively with some medications. You should also avoid taking melatonin if you are on blood thinners or other anticoagulants.

How Long It Lasts

Melatonin is absorbed fast by the body. An oral melatonin supplement should cause drowsiness within one hour of taking it. You should feel the peak level of sleepiness at about the one hour mark. 

Keep in mind though that all drugs affect people differently. Some people may not feel tired at all until one hour of taking melatonin. Others may begin to feel tired as quickly as within ten to fifteen minutes.

How fast your body absorbs melatonin can be affected by several factors such as age, caffeine consumption, smoking and tobacco use, overall health, and body makeup. Melatonin may last longer in the bodies of older, heavier, individuals. Caffeine and smoking may cause the drug to last for a shorter amount of time. 

The absorption time can also be affected by your tolerance to melatonin. If you take the substance regularly, it may take longer for your body to ingest it. 

So how long does it last? Melatonin has a half-life of 40 to 60 minutes, meaning that it would stay in your body for roughly five hours. A half-life describes the time required for the body to eliminate half of a drug. Most drugs can be completely eliminated within four to five half-lives. 

Never take melatonin before driving or operating heavy machinery. Doing so can lead to severe consequences. Remember that you are essentially impaired, both physically and mentally when you’re sleepy. 

Regular vs. XR

Another factor in how long melatonin lasts is what kind of supplement you are taking. Most standard melatonin products are immediate release supplements. This means that as soon as you take them, melatonin is released immediately into your bloodstream. 

Alternatively, extended release supplements dissolve into your bloodstream gradually. An extended release melatonin supplement will slowly deliver small amounts of the drug to you throughout the day. 

This process is supposed to imitate how your body naturally produces melatonin throughout the night. If you have trouble staying asleep at night, extended release melatonin tablets may suit you better. 

Extended release melatonin may also be labeled as slow release melatonin, continuous release melatonin, time release melatonin, prolonged release melatonin, or controlled release melatonin. All of these names are the same type of melatonin. 

If you’re unsure of what type of melatonin fits your situation, contact your health provider. A doctor can better assess your sleep patterns and decide what is the best option for you. 

Dosage Control

Though melatonin is an OTC medication, you still have to be responsible in how you take it. Taking too much melatonin or taking it too often can affect how your body naturally produces the substance. 

A moderate dose of melatonin should consist of one to five milligrams. When first starting out, it is recommended to start at the lower end, with just one milligram. It is possible to overdose on melatonin. 

Once you become comfortable with the effects of melatonin, you can begin increasing your dosage little by little. Decide what dosage provides the perfect sleep for you. 

One crucial note is that melatonin is not stringently regulated by the Food and Drug Administration (FDA). To the FDA, melatonin is technically not a drug. As a result, it can be sold as a dietary supplement just like any vitamin or mineral. Vitamins and minerals generally are not examined closely by the FDA.

Because of this lack of regulation, manufacturers of melatonin products, as well as any dietary supplements, can basically list whatever they want on their nutritional facts. There is nobody testing to confirm that the ingredients listed on a supplement are accurate. 

For example, a brand that creates melatonin supplements may list on their packaging that their supplements contain five milligrams of melatonin per tablet. However, they very well could include just one milligram of melatonin per tablet. And they’d still be able to sell it legally. 

With how oversaturated the supplement market has become in recent years, there is also little quality control. Always do your research on the brands you choose to support. And always read reviews on the products. 


In general, you should only take melatonin when you are struggling heavily to sleep or are in desperate need of a good night’s sleep. Perhaps you’ve tried to sleep for an hour and need a melatonin to help push you over the edge. Maybe you have an important business meeting the next day and you need to be in tip-top shape to perform. 

From time to time, it is okay to take melatonin supplements. They should not be relied on though. Doing so will disrupt your circadian rhythm and make it even more difficult for you to sleep in the future.  Your first priority should always be your health.

For a safe and reliable sleep aid, check out our sleep gummies on the Shop Hope official site. They’re packed with melatonin and botanicals to support a deep, healthy sleep. 



How Long Does Melatonin Last in Your System? Dosage, Efficacy, More | Healthline 

How Long Does Melatonin Last in Your System? | Amerisleep 

Hypothalamus: Anatomy, Function, Diagram, Conditions, Health Tips | Healthline 

Circadian Rhythms | NIH