How Long Does Melatonin last?


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Written by Phillippa Quigley

Health Coach Phillippa Quigley takes a look at Melatonin and asks the question – how long does melatonin last? She answers that, and a lot more about the sleep inducing hormone below…

Melatonin is naturally produced within our body. It helps with our sleep wake cycle. In this article we will discuss how we get melatonin, it’s benefits and how supplementation could be beneficial.

But first, let’s look at how long Melatonin lasts.

Melatonin will stay in your body from four to eight hours. However, this will range from individual to individual and it is important that we fully understand melatonin to answer the question in detail…

What Is Melatonin?

Melatonin is a hormone that your brain naturally produces in response to darkness. The pineal gland is the exact location within the brain, where it is made. Melatonin helps regulate the timing of your circadian rhythm. 

The circadian rhythm is your body’s internal clock. It helps carry out cycles of sleepiness and alertness, which respond to changes within light around us. Your circadian rhythm is basically what tells your body to sleep and be awake over a 24 hour period. 

Melatonin is produced naturally from an amino acid called Tryptophan. Levels of melatonin in our body are at a peak at night time. Our eyes detect night time via the retina and optic nerve, through less light entering in to them. Once melatonin has been produced, signals are sent to organs around our body, this is done by its secretion into the blood stream and spinal cord. 

With the change in seasons of the year, and daylight hours in a day. Melatonin levels vary depending on the time of year; with higher levels in Autumn and Winter, and lower levels in Spring and Summer. 

In animals, Melatonin plays a slightly different role. The release of melatonin from the Pineal Gland helps an animal’s body regulate it’s biology in response to the season. With the change of the day length, it impacts their reproduction, coat growth and behavior. 

The Effects Of Melatonin On Our Body

When it gets dark, the process of melatonin and sleep begins. Once our pineal gland starts to secrete melatonin, our body starts to prepare to sleep. Our blood pressure lowers, as does our stress response. Our body temperature begins to lower and our alertness levels reduce. This is the time where you’ll notice you feel sleepy.

Going to bed during this process is what will result in you having good quality, restorative sleep. You will find it easier to fall asleep quicker. It is also what helps keep our circadian rhythm regulated. 

Low Levels Of Melatonin

Some people can struggle with their levels of melatonin. If you don’t produce enough it won’t be able to prepare your body for sleep. This would then affect your ability to fall asleep as well as the quality of sleep you will have. 

What can cause low levels of Melatonin in your body?

  • Alcohol
  • Working shifts
  • Smoking
  • High caffeine consumption in a day
  • Age
  • Diseases such as; Alzheimer’s, dementia, type 2 diabetes etc.

High Levels Of Melatonin

You can also suffer from having too much melatonin in your body. 

When the days are shorter in the fall and winter, you can end up not getting enough exposure to daylight. This will signal to the brain to over-produce melatonin. When we have too much it results in Season Affective Disorder (SAD). SAD is when a person experiences symptoms of depression but only in the winter. 

Treatment for this would be ensuring you get outside, especially in the morning that to help regulate your circadian rhythm. 

How Can We Naturally Make Melatonin?

We know that the melatonin is produced in the brain. However, how much you make as an individual can be different based on certain factors, such as;

  • Genetics
  • Gender
  • Age
  • Lifestyle

Therefore if you are looking to boost your level of melatonin, consider some of this advice.

Reduce Artificial Light

Getting ready for bed should be a relaxing and calming process, however, most people still do not value this time as an important part of their health. 

As mentioned before, our circadian rhythm works best when we expose ourselves to natural light in the morning, and then darkness later in the day. If we then sit on an electronic device for a long period of time in the evening, it will no doubt interfere with our body’s Melatonin production. 

If you sit on your phone reading (which I think many of us will be guilty of), you can cause your circadian rhythm to be come misaligned which will affect your sleep-wake cycle, as well as negatively impacting your quality of sleep. 

Morning Sunlight

To counter the need to reduce artificial light at night time, it is key to also get outside into natural light as soon as you can in the morning. 

When we get sunlight, we produce the neurotransmitter Serotonin. Serotonin is the precursor to Melatonin, therefore we need one to get the other. 

Bedtime Routine

If you’re a parent, you’ll know just how much you will obsess over your baby’s bedtime routine. The routine will be a point of discussion with your spouse, fellow parents and just about anyone who asks you the dreaded question ‘Do they sleep well?’

When you can finally answer ‘yes’, you feel triumphant! 

The point being; bedtime routine is absolutely key to any baby – and adult!


The production of Melatonin. Follow the tips to below to ensure a good bedtime routine. 

Have a Bath

Bath and bed with a child works wonders, and it will for an adult as well. During the day our body will go through metabolic changes. When melatonin is produced, your core temperature drops as your body prepares you for sleep. 

If you take a warm bath before bed, it will help create the dropping of the core temperature once you step out of the bath. This will help in making your body feel tired and relaxed. 


Having a lot of things on your mind at bedtime can often stifle the relaxing state we are trying to acquire when falling asleep. Meditation is a good practice to introduce. It helps you manage your thoughts and feelings better, and become more mindful. 

Being able to meditate and clear your mind before bed will definitely improve your quality of sleep. There are plenty of free guided mediations available online for you to try.


Read a book, not your phone. Reading without the blue light from your phone or tablet, is really beneficial in creating a relaxing state. It helps ease tension, it slows our brains down and induces a restful sleep.

Other things you can add to a bedtime routine are; yoga, journalling, listen to music, drinking a bedtime tea. It is also important to consider your bedroom environment. 

Melatonin Supplements 

Most people can take melatonin supplements. However, it is always recommended that you try and naturally increase your level of Melatonin in your body before using a drug form. For some this is quite simple and can be achieved through diet, lifestyle changes and good sleep hygiene.

For others, these changes aren’t possible or suitable. This is where supplementation has a purpose.  

It also plays a role for people who have sleep problems due to;

  • Shift workers: People who work at night will be resting and trying to sleep through daylight hours
  • Jet lag: When you land in a new time zone, taking Melatonin can help your body adjust faster.
  • Blindness: Melatonin supplements can help address circadian rhythm disorders.
  • Sleep-wake cycle problems due to disability

Normally, our body makes the most amount of melatonin a couple of hours before bedtime. Once these levels are high, you will start to feel sleepy not long after. 

Depending on what form of melatonin supplements you take, it will affect how quickly they work and for how long. You can find supplements in various forms now. They are available in gummy, liquid, pill form and even patches. Some of them are made from natural melatonin or synthetic melatonin. Tart cherry supplements are naturally rich in melatonin and are a good example of a natural supplement.

‘Natural’ Melatonin supplements are sourced from animals. They take it from an animal’s pineal gland. As much as natural products are more desirable than synthetic, the risk of this is possible exposure to bacteria and viruses. 

How Long Does It Take For Melatonin Work?

As with anything, how long it takes our body to absorb something will differ from person to person. On average, a melatonin supplement could start working within 20–30 minutes, or take up two hours. 

Again, depending on the individual, how long the melatonin will stay in your body will be different. It can range from four to eight hours. 

Factors that can affect how long melatonin is in your body include:

  • Dose you have taken
  • Type of Melatonin
  • Caffeine levels
  • Age
  • Weight
  • Exposure to light 
  • Other medications you might have taken
  • Any alcohol consumption

It is worth noting that because it is their to aid sleep, taking a larger amount of melatonin won’t help it work faster or better than a small amount. It is recommended to start with a small amount, and take it at a suitable time for you. For example, not when you still need to drive a car or operate any type of machinery.

Taking melatonin at the wrong time of day can disrupt your body’s sleep-wake cycle more than it may be already. You will want it to support your body in improving its internal clock and your general sleeping habits.

Always follow the instructions of any supplement you take.

For some, it is not suitable to take melatonin. Anyone who has suffered with or has had:

  • Any previous allergic reactions to medicine
  • Liver or kidney problems
  • Depression
  • Any autoimmune condition
  • Might be pregnant or are breastfeeding

Whenever you decide to introduce a new supplement into your body, it is always recommended that you speak with a healthcare provider.

Further Health Benefits Of Melatonin

You can choose to supplement Melatonin, or make a pro active choice to increases your levels naturally, to simply improve your sleeping habits. However, there are other times when Melatonin supplements can be advised. 

These additional health benefits are;


Migraines are headaches that cause moderate or severe pain. This pain can a throbbing feeling on one side of your head. They can also cause nausea, vomiting, loss of vision and in some cases numbness in the body. 

There has been some research that suggest that people who suffer with chronic migraines may have a low level of melatonin production. Therefore, it is possible that using melatonin could help reduce the amount of migraines a person could suffer. There is still more research and evidence needed to prove if this effective.


It has been found that melatonin can be beneficial in treating eye condition such as glaucoma and AMD; Age-related macular degeneration. AMD is an eye disease that affects the middle part of your vision. It tends to happen to people in their 50s and 60s. 

Melatonin contains antioxidants and they help prevent cell damage. It is thought that it helps protect cells in the eye from oxidative damage. 


Tinnitus is an ear condition that gives a sensation of ringing, hissing, buzzing or other such noises, in the ear – yet there is actually no sound been made around them. Each person’s symptoms suffering with Tinnitus will vary from the next person. 

There was been research that suggests that taking melatonin can decrease the intensity of the Tinnitus a person is suffering with. It also can improve their sleep. Again, its antioxidant properties are also beneficial to a person living with this condition. 

Acid Reflux

Gastroesophageal Reflux Disease, known as GERD, is a condition that regularly affects your Esophagus. The esophagus being the tube connecting your throat and stomach. Reflux is when your stomach acid flows back into this tube which then causes uncomfortable heartburn and leaves a sour taste in your mouth. 

Whilst there isn’t much research in this area yet, there was some initial findings that taking Melatonin regularly helped reduce and ease the symptoms of GERD.  

Head Trauma

It is thought that people who have traumatic brain injuries (TBI) can end up with sleep problems. This may be because a person who has suffered trauma to the brain may produce lower levels of melatonin. They may also end up suffering with insomnia and problems with their sleep-wake cycle. 

Research has suggested that Melatonin can help a person not only with their sleep but also have anti-inflammatory affects in the brain, post injury. 

Side Effects Of Melatonin supplements

Melatonin supplements are thought to be safe and non-addictive. It is also thought that supplementing will not affect your body’s ability to make its own.

Common side effects of taking melatonin supplements are thought to be;

  • Headaches
  • Dizziness
  • Daytime drowsiness and feeling sleepy
  • Nausea

More serious but less common side effects may be;

  • Depression
  • Anxiety
  • Joint pain
  • Seizures
  • Abdominal Pain
  • Allergic reaction

Whilst it appears to be a safe form of supplementation, you should be aware of possible interactions with other medication and supplements. 

These may include;

  • Antidepressants
  • Blood pressure medication
  • Diabetes
  • Birth Control
  • Anti-inflammatories
  • Pain killers such as codeine
  • Warfarin


Some might argue that sleep is one of the most fundamental parts of our health. Without high quality, restorative sleep the impact to our health can be huge. 

If you suffer with poor sleep, then finding a way to improve this is key. We now know that melatonin plays a big role in this. Your first step should always be to find a way to naturally boost these levels. Consider some of the advice suggested in this article to see if makes a difference. 

However, you can consider supplementing melatonin. Start with a low dosage, and see how you get on. You must make sure that you first talk with a healthcare provider to find out if it is a suitable option for you. 

Phillippa Quigley headshot

This article was written by: Phillippa Quigley – SOMA Analytics Nutritionist and Holistic Health Coach

Phillippa is the owner and founder of Health and Soul and coaches and supports clients in the field of women’s health, nutrition, stress management, lifestyle, mindset, weight loss and general fitness.

She has a young family, loves the outdoors and has a wide range of hobbies that help her manage her own mental and physical health.