Melatonin – All you need to know about the Sleep Hormone!

Melatonin – All you need to know about the Sleep Hormone!

Melatonin can be the solution for sleep disorders. We all know that sleeping is crucial for health and to preserve our vitality. But, what is melatonin? We will explain it in this article.

Melatonin is the hormone that regulates the sleep-wake cycle. However, the organism needs a considerable amount in order to benefit from its effects.

According to a recent study, one out of three adults does not have a regular sleep pattern.[1]

Melatonin supplements are used to treat sleep problems, insomnia and jet lag. Clinical research has shown that melatonin can help cancer patients, specially those who are diagnosed with breast or prostate cancer. This is due to the fact that these two types of cancer are related to hormones, which is why melatonin plays a crucial role in their treatment.[2]

Our organism produces melatonin naturally, but other elements like caffeine, alcohol, tobacco, stress, or evening work shifts can reduce the amount of this element in the body. Melatonin dietary supplements can contribute to regulating the sleep patterns in these cases.


What is Melatonin?

It (N-acetyl-5-methoxytryptamine) is a hormone that is released by the pineal gland in the brain. The pineal gland is in the center of the brain and it has the size of a pea.

Apart from being produced naturally by the organism, It is usually consumed through food or supplements. Its consumption has increased in the last years due to its benefits for health and to the fact that it is related to the regulation of the biological rhythm: it plays a crucial role in the natural sleep-wake cycle.

Melatonin could also shorten the time it takes to fall asleep, even though this effect tends to be mild.

The natural melatonin levels in the blood are higher at night. Some research suggests that if we take melatonin supplements at the right moment, like before going to sleep, they could be useful for the treatment of jet lag and other sleep problems that involve a maladjustment of the circadian rhythms.

One of the conditions to stimulate the synthesis and release of melatonin is darkness, while light suppresses it. It is also produced in other organs of the body, specially in the stomach. [3][4]

The organism is able to maintain its biorhythm thanks to melatonin. The term biorhythm refers to the internal clock of the body that has a 24 hours cycle, like a day. This internal clock plays a crucial role in the sleep-wake cycle as well.

Melatonin to sleep

The circadian rhythms respond to the biological functioning of living beings, the beginning and the end of the 24 hours cycle is signalled by the light-darkness pattern of the day. This “internal or biological clock” is made of a molecular network of cells of the whole organism, which are ruled by the central unit (brain), in a specific region, the suprachiasmatic nuclei, which is formed by a type of nerve cells.

This central clock is the one responsible for keeping the entire system synchronized.

Some of the conditions that mainly affect our sleep-wake cycle are excessive lighting before going to sleep, undergoing a lot of stress, long trips (jet-lag syndrome)…

The sleep-wake pattern influences the release of hormones, body temperature, and important functions of the organism. The symptoms of a bad regulation of this rhythm are related to obesity, diabetes, depression and seasonal depression, or bipolar disorder, which are some serious health problems.

The circadian rhythms are essential to determine human sleep patterns apart from the proper functioning of the hormone axis, which will keep a close relation with the behavior and mood of a person.

Fortunately, melatonin supplements can contribute to reestablishing the balance of the circadian rhythm in the body safely and effectively. This important hormone helps to achieve a restful sleep and to keep the biological clock synchronized.

Artificial light reduces melatonin

Effects of Melatonin

When there is darkness, the pineal gland releases this substance. When the organism perceives light, its production drops. This is the reason why blind people or those who work at night can have health problems related to melatonin. However, it is clear that anyone who lacks light during the day or who is subjected to a bright light during the nighttime will alter the normal melatonin cycles of his or her body.

The exposure to light stimulates a nerve that travels from the retina to an area of the brain called hypothalamus that travels to the suprachiasmatic nuclei and triggers the activation of the pineal gland.

The release of melatonin takes place according to the circadian rhythm response to the diurnal or nocturnal circulation. In fact, the enzymes that synthesize it in the organism are activated or deactivated depending on the light conditions. This timed function is the one that gives melatonin its state as a chronobiotic compound.

Once the suprachiasmatic nuclei has activated the pineal gland, melatonin enters the bloodstream. Its precursor is serotonin, a neurotransmitter that comes from the tryptophan amino acid. Serotonin is transformed into melatonin in the pineal gland.

The production of melatonin is closely linked to the light sensors in the eye. In general, the pineal gland starts to produce it around 9 pm. The levels increase and we start to feel sleepy. Usually, it stays high while we sleep for approximately 12 hours. Then it starts to fall at 9 o’clock in the morning to an almost undetectable level and it stays like this for the rest of the day.[5]

The concentration of melatonin reaches its highest peak between 2 and 4 o’clock in the morning, and then falls once again during the day. At the same time, the cortisol levels in the blood increase, which is what makes up wake up in the morning. Cortisol drops again during the nighttime and melatonin increases.

There is less daylight during the winter, which means that the production of melatonin does not stop completely during the day, which is why it is more common to feel tired or low during the day.

Physical activity during the day and exposure to light favor the stimulate the normal rhythm of melatonin and guarantee increased levels during the night.

Small children have the highest melatonin levels. Many researchers are convinced that we lose this ability as we grow old.[6] If this is true, it would explain why the elderly sleep worse than young people.

Melatonin is a complex neurotransmitter that is obtained from serotonin and which is mainly produced in the pineal gland in the brain. Its role consists on regulating the biological rhythm and to adapt the organism to the diverse biological processes.

Melatonin receptors

It works by interacting with two protein receptors, MT1 and MT2.[7]

The MT1 and MT2 receptors control the different stages of sleep: MT1 control deep sleep or REM, and MT2 controls the phase that takes places before dreaming.[7]

These receptors are present in several organs and immune cells, which suggests that melatonin also controls the immune function, as well as other processes of the organism.[8]

Benefits of melatonin for health

Everyone knows that sleeping well is very important for health, as well as for countering acute and chronic disorders.[9] According to a Study from the Disease Control and Prevention Center, one out of three adults does not sleep enough.

Melatonin affects our sleep and the circadian rhythm. It is like a clock for the organism, since it controls biological processes in a cycle of 24 hours approximately.[10]

This central clock is located in the brain, the SCN (Suprachiasmatic Nuclei) of the anterior hypothalamic nucleus and it controls the circadian rhythm. The circadian rhythm helps to control the sleep-wake cycle, the body temperature, and the production of hormones.[10]

The environmental light affects those signals sent by the SCN. The pineal gland produces and release melatonin under the command of the circadian rhythm. Under normal circumstances, it is eliminated during the nighttime. Its levels remain undetected in the blood with the light of day.

Most scientists believe that melatonin can revert the circadian rhythm phase and change it, even though this property is arguable.[11]

The brain and the pineal gland

Apart from sleep and circadian rhythms, melatonin has many important benefits for health, since it is a powerful antioxidant with anti-inflammatory power. To this, we should add that it also favors the health of the brain, the intestine, and fertility.

Clinical research has shown that it can also benefit patients who suffer cancer, specially those who have been diagnosed with breast or prostate cancer, since they are linked to hormones.[12]

Therefore, it makes perfect sense that a hormone like melatonin will play a crucial role in their treatment.[13][14]

Melatonin is also essential for the reproductive function in healthy women, since it performs an important task in the timing and release of female reproductive hormones. It also marks the beginning of the menstruation, as well as the frequency and duration of menstrual cycles and the moments menstruation stops completely (menopause).

It performs many important functions in the organism, some of them are:

  • Regulating the circadian rhythm
  • Supporting the immune system
  • Helping with the ocular function
  • Reducing the oxidative stress
  • Encouraging sleep
  • Regulating the female reproductive hormones
  • Controlling many cell processes, including the synthesis of important molecules
  • Protecting against radiation

Healthy sleep

A good quality of sleep is a must for a good health, however, many of us have problems to fall asleep sometimes. Insomnia happens due to a lot of factors that go from working a lot of time, to travels, or events that interrupt our sleep, like the frequency to urinate or stressful events.

Old adults can be particularly susceptible to sleep problems and to waking up in the middle of the night due to a decrease of melatonin related to aging.

It can encourage healthy sleep habits in some cases, regardless of what causes the insomnia, and specially punctually.

Migraine prevention

A promising study suggests that the frequency and severity of headaches caused by migraines can be reduced though the use of Melatonin. Scientists believe that its anti-inflammatory effect as well as its ability to deal with the radicals contribute to relieve headaches.

Fighting cancer

One of the most important uses of melatonin is to fight against several types of cancer, including breast, prostate, and liver cancer, as well as lung cancer, and brain metastases of solid tumors.

Apart from its benefits to overcome cancer, melatonin can also help to counter the toxicity of chemotherapy. After a year, those who have used supplementation have shown a higher survival rate, and they were significantly more protected to many of the side effects that are related to chemotherapy, including a decrease of platelets, neurotoxicity, damage to the heart, mouth ulcers, and fatigue.

Neuroprotective benefits

Melatonin is a powerful and versatile antioxidant element that is produced by the body. It protects the lipids and proteins against damage, and they can find some of the most dangerous free radicals in the body, including the hydroxyl radicals and hydrogen peroxide. Unlike other antioxidant agents, melatonin easily blends in with all the cells, and it even crosses the blood-brain barrier to protect the delicate brain tissue.

Melatonin supplements can support those adults who want to enhance their antioxidant protection against some of the diseases related to aging that cause more damage, such as Alzheimer, Parkinson, and cerebrovascular diseases.

Regulate the menstrual cycle

Melatonin also controls the timing and release of female reproductive hormones. As a result, melatonin determines when the menstruation begins, the frequency and duration of the menstrual cycles, and when the menstruation ends (menopause).

Why does a melatonin deficiency happen?

There are several reasons why the release of melatonin can be poor and interfere with our rest or cause sleep problems:

  • The body produces less melatonin as it grows old because the pineal gland calcifies with time. Due to this, the quality and duration of sleep decreases. This is the reason why a 40% of the elderly often complain about sleep problems (insomnia). These problems go from the inability to fall asleep to a poor quality of sleep.
  • Artificial light and the blue light from screens (TV, computers, telephone, etc.) can reduce the release of melatonin. This is why we have to avoid light sources in the bedroom, including the stand by lights of electronic devices.
  • Those who work at night have problems to sleep throughout the day due to the fact that the pineal gland does not release enough melatonin in the morning.
  • Those who spend the day in a dark space or who sleep a lot can also alter the circadian rhythm and the release of melatonin.
  • Constant stress and intense sports carried out during nighttime also lower the release of melatonin.
  • Consuming caffeine, alcohol and nicotine also lower the release of melatonin.
  • Certain medicines also have the same effect, specially beta-blockers, cortisone, or ASA.
  • Those who suffer certain diseases (like Addison’s disease, autism) and blind people can also have a low release of melatonin.
  • A serotonin deficiency can also reduce the production of melatonin.

Melatonin dietary supplements

Melatonin is available in different formats: capsules, tablets, liquid drops and/or sublingual tablets that are dissolved under the tongue.

Is it possible to suffer a melatonin overdose? Like it happens with any other dietary supplement or medicine, it is possible to take too much melatonin. Most of doctors and researchers advise not taking more than 5 milligrams daily, but the recommendations can change from one person to another, apart from the specific indications of the product. The melatonin tablets are the ones that are most frequently used, specially melatonin sublingual tablets, since they are quickly absorbed by the organism.

There is not an established recommended dose of melatonin, since each person reacts differently to its use. It works more effectively in those who are very sensitive to the lowest doses.

Melatonin and Sport

One of the main benefits of melatonin for sportspeople is its antioxidant property. The workout requires a higher metabolic use of oxygen, which encourages pro-oxidant responses. Melatonin is a great protector against the oxidative damage produced by intense exercises due to its composition. Apart from concentrating in the pineal gland, it can also be found in organs like the retina, immune cells, the intestine and the bile, where it performs an antioxidant task against the effect of oxidative stress on these organs.

Melatonin protects the cells from the oxidation that is produced by the free radicals, which also performs an anti-aging function. Moreover, this hormone helps to avoid the onset of fatigue, chronic tiredness, somnolence, and a lack of energy.

Apart from a proper training and a healthy diet, rest is indispensable for the health of sportspeople and also to gain physical benefits. The quality of sleep not only helps to recover the necessary energy, but it also makes sure that those processes that occur while we sleep are properly executed. During sleep, the heart makes less effort and it benefits from the growth hormone and melatonin.

Melatonin during Old age

Melatonin and Sleep Disorders

The intake of melatonin can correct sleep-wake disorders, as well as sleep problems.

The studies have shown that as we age, melatonin drops, which negatively affects the amount and quality of sleep.

The suprachiasmatic nuclei activates or accelerates the release of melatonin through the pineal gland due to the light stimuli on the retina.

These systems mainly use the GABA neurotransmitters to have an inhibitory control on the activation systems during sleep. After activating rest mode, the body releases neurotransmitters like norepinefrine and acetylcholine to counter sleep and keep us awake.

Clinical test show that melatonin, as a chronobiotic element, is a substance that determines the temporal biological rhythm and it can improve the quality of sleep.[11] Morever, the use of melatonin shortens the periods between the wake-sleep phases, apart from improving the quality of sleep.

Melatonin can be used to treat several diseases, including the following ones:

  • It helps to treat primary sleep problems or other disorders caused by beta-blockers and other type of medicines.
  • It helps to treat narcolepsy, a chronic neurological disorder which is characterized by somnolence during the day.

Melatonin helps to sleep in a natural way

Melatonin has been commonly used as a natural substance that helps to sleep. In the case of sleep problems, the conventional medical treatment generally turns to medicines. However, this type of medicines tend to cause dependency problems in the long term and they have a long list of contraindications. This is the reason why many prefer a natural product to get a good night rest.

Clinical research suggests that melatonin helps with unbalanced biorhythms, as well as those who work during night shifts or who suffer jet lag. Melatonin supplements can also support those who have chronic melatonin and schizophrenia to sleep better.

A study published on “Drugs & Aging” in 2012 analysis the effects of a prolonged release of melatonin to treat insomnia in patients over the age of 55.

The European Union approved a prolonged release of 2 milligrams of melatonin for the treatment of primary insomnia characterized by a bad quality of sleep.

A random double-blind study found out that two milligrams of PR melatonin one or two hours before sleeping significantly improve the amount and quality of sleep and a better state of wakefulness in the morning, which improves the quality of life as well.

A study also showed that if the dose of melatonin (2 milligrams) was taken in the short or long term, it would not produce any dependency, any tolerance problem, nor rebound effects regarding insomnia or abstinence symptoms.[15]

Melatonin favors the production of the Growth Hormone

According to research, melatonin stimulates the production of the growth hormone (GH). If we take into account that the growth hormone is released during sleep and melatonin helps to improve the amount and quality of sleep, we can confirm that these two hormones are closely linked.

Melatonin to sleep like a baby

How can you optimize your melatonin levels?

When the body is exposed to artificial light during the nighttime, it interrupts the natural production of melatonin.

Melatonin plays an essential role in the prevention of cancer and the strengthening of the immune system. Now, it is being studied if it can also slow down cell aging. Melatonin is an essential substance achieve a restful sleep.

In the last century, industrialized countries have tried to prolong the day and shorten the evening to gain productivity. But the light pollution produced by modern technology has a serious biological effect on human beings.

Some of the factors that difficult sleep are light pollution and temperature. The following tips can help you to improve your quality of sleep and to optimize the production of melatonin.

  1. Avoid watching the TV or using the computer or mobile phone at least an hour before going to sleep. These devices emit blue light that tricks your brain into believing that it is daytime. Normally, the brain starts to release melatonin between 9:00 p.m and 10:00 p.m, these devices emit a light that can interrupt this process.
  2. Make sure to sunbathe regularly. The pineal gland produces melatonin when there is a bright sunlight in contrast with the darkness of the night. If you spend the whole day in darkness, the production of melatonin will be disoriented and not optimized.
  3. Sleep in complete darkness or with as much darkness as possible. A little bit of light in your bedroom can alter your biological clock and the production of melatonin. Even the light of the alarm clock can affect your sleep, which is why it is better to cover the device or to get it out of the room. Put all the electronic devices at least three meters away from the bed. It is also good to use thick and opaque curtains for the windows.
  4. If you need a source of light at night, get a orange or red low voltage bulb. These colors do not lower the production of melatonin like a white or blue light.
  5. Keep the bedroom temperature under 21 degrees C. Many houses with rooms that are too hot (specially rooms on the top floor). The studies show that an optimal room temperature to sleep would be between 15 and 20 degrees C.
  6. Take a hot both from 90 to 120 minutes before sleeping. This increases the central temperature of your body so that your body is ready to sleep.
  7. Avoid loud alarms. Waking up with a loud noise in the morning is very stressful. If you sleep enough, you may not even need an alarm anymore.
  8. Sunbathe in the morning as soon as possible. Your circadian rhythm needs bright light to reset. 10 to 15 minutes of sunlight in the morning sends a strong message to your internal clock that signals that the day has started. As we grow old, we need more sunlight. To take full advantage of sun, leave your sunglasses at home and avoid using artificial light in the morning.
  9. Pay attention to the electromagnetic field of your bedroom. The electromagnetic fields can alter the pineal gland and its production of melatonin, as well as other negative biological effects. If you want to measure the EMF levels of your home you will need a Gaussmeter or a digital magnetic fields measuring device.
  10. Take melatonin dietary supplements. We advise taking 0.5mg daily approximately. Taking melatonin orally can affect the liver and most of it will not reach the blood flow. This is why we advised using sublingual tablets. It is easier to absorb and work faster, it is the most effective way of taking melatonin.

Foods that increase Melatonin

The tryptophan amino acid is transformed into serotonin, and the pineal gland transforms serotonin into melatonin at night. Foods with a high tryptophan content can increase our melatonin supply. The best tryptophan sources are milk and dairy products, soy, seafood, meats, peanuts, and eggs. Eating carbs with tryptophan improves the production of melatonin.

The tryptophan amino acid helps to control anxiety, stress, and insomnia.

Vitamin B5 or pantothenic acid is part of a coenzyme that is essential for melatonin synthesis. Some of the best sources of vitamin B5 are the same as the tryptophan ones, like milk, yogurt, eggs, and fish, specially tuna and cod. Other sources are broccoli, sweet potatoes, mushrooms, and lentils.

Therefore, some of the best sources to stimulate the production of melatonin are:

  • Nuts (mainly walnuts and almonds)
  • Milk
  • Fruits (specially bananas, tomatoes, cherries)
  • Cereals (oats, rice, corn)

Natural sources of melatonin

Melatonin: a powerful antioxidant

Most of the benefits for health of melatonin come from its powerful antioxidant properties, both directly and indirectly.[16] The administration of melatonin increases the cell production of antioxidant enzymes (superoxide dismutase, glutathione peroxidase, and γ-gamma glutamyl cysteine synthetase) and it multiplies the antioxidant agents like glutathione.[17][6][18]

These enzymes help to purify the cells, mitochondria, and to protect the bloodstream from harmful substances from reactive oxygen.

Moreover, the melatonin molecule can bind to reactive oxygen species (ROS) and reactive nitrogen species (RNS), making them less harmful.[6] This allows melatonin to protect multiple tissues and organs from oxidative damage. The tissues that produce melatonin are the intestine, ovaries, testicles, lens, bone marrow, and brain.[19]

Melatonin transforms into molecules (metabolites) which also have the ability to bind to harmful oxygen and nitrogen, which means that melatonin provides an effective protection.[6]

A single melatonin molecule can neutralize up to 10 molecules of ROS and RNS.[20] Moreover, melatonin also blocks an enzyme called nitric oxide synthetase which produces reactive nitrogen species which causes inflammation.[21]

Melatonin protects the mitochondria

The mitochondria is the part of the cell that produce energy. They have their own DNA. They are crucial for our survival, like energy factories. The nucleus and the mitochondria are the areas of the cell that has more melatonin.[22]

The production of mitochondrial energy produces reactive oxygen species (ROS) and reactive nitrogen species (RNA). ROS and RNA damage the DNA and the mitochondrial proteins, which inhibits the energy production. This damage can also lead to a loss of the mitochondria, which causes cell death (apoptosis).[6]

Therefore, melatonin is beneficial for the organs that are dependent on the mitochondria, which includes the heart and nervous system.

It protects the mitochondria against toxins

When several toxins affect the mitochondrial function it can result in neurodegenerative diseases symptoms. Laboratory animals poisoned with these toxins are used as models to study this type of diseases.

Melatonin protects against the oxidative damage caused by these toxins and it helps to reestablish the normal cell functions. Some of these toxins are:

  • Rotenone, a toxin that reproduces Parkinson’s disease in mice.[23]
  • MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine), another toxin that reproduces the symptoms of Parkinson’s disease.[24] After injecting MPTP to mice, Melatonin prevents the damage to the fat molecules, the DNA, and many areas of the brain. It also stimulates many important proteins so that they can go back to their normal state.[25]
  • 3-NPA, is a toxin from the fungus that infects sugar canes. There have been cases of children who have develop disorders similar to Huntington disease after eating contaminated sugar cane. Melatonin prevents the loss of nerve cells and the damage to the proteins and fat molecules in mice who have been administered this toxin. It also corrects the harmful behavior and restores the dopamine levels.[26]
  • Cyanide is an extremely deadly poison which causes the massive death of nerve cells. It triggers convulsions and death.[27][28] Moreover, it also damages the mitochondria from the nerve cells. A preventive melatonin treatment in mice that were injected cyanide reduced the severity of the convulsions.[27] Melatonin also protects the mitochondrial DNA against the damage caused by potassium cyanide in mice and their reproduction.[28]

Melatonin and jet-lag

Jet-lag is a temporary sleep problem suffered by those who travel and go through several time zones. This happens due to the slow adaptation of the internal clock to objective time, which results in an unsynchronized sleep-wake cycle.[10]

If you suffer jet-lag, melatonin can help to reestablish the sleep-wake cycle.Melatonin for jet lag

A scientific review carried on a great number of studies with melatonin and jet-lag points to the fact that melatonin “is highly effective to prevent or reduce the jet lag and an occasional intake in the short term seems to reduce the effects of jet lag.”

Research has revealed that (around 10 p.m) there is a decrease of jet lag when crossing five or more time zones. Jet lag was relieved by taking melatonin before going to sleep in nine out of ten cases.

Researchers also observed that the daily dose of melatonin between 0.5 and 5 milligrams worked equally well, but the subjects fell asleep faster and slept better after taking five milligrams when compared to those who took 0.5 milligrams.

There is no evidence that a melatonin dose higher than 5mg provides better results. Another important conclusion is the moment when the dose is administered, since taking it too early can delay the adjustment to the new time zone. The onset of other side effects caused by the melatonin dose is very low.[29]

Melatonin and Sleep for the Elderly

The effects of sleeping pills made of melatonin have been widely studied in old people.[30] It is known that melatonin can benefit the elderly who suffer insomnia, since the production of this hormone drops gradually with age. This is why there are research lines focused on studying melatonin as an anti-aging supplement.

The elderly suffer more the side effects of melatonin, like morning somnolence, even though they also obtain more benefits. It is advisable to always take a low dose, between 0.1 to 0.3 milligrams, instead of higher doses. It has been discovered that melatonin is more effective in lower amounts and causes less problems.

The properties of melatonin to sleep better have been studied in depth. Even though the effects are not completely known in the long term, it has been proven that you can take high doses with absolute confidence for three years with almost any issue.

Melatonin to treat insomnia, anxiety, depression, and bipolar disorder

Melatonin helps to treat sleep problems related to anxiety and depression. Depression and other mood alterations tend to be linked to sleep problems and they need the administration of relaxing and calming remedies. The medicines that activate the MT2 receptors are therapeutic agents designed for the treatment of these diseases.[31]

Abnormal concentrations of melatonin during the day and night tend to indicate the level of depression.[32]

Melatonin helps to regulate depression in patients that suffer the delayed sleep phase syndrome.[33]

It has been tested in laboratory mice that melatonin relieves chronic depression produced by stress and it significantly changes the brain dynamics of these animals.[34]

The treatment with melatonin in breast cancer patients reduces the risk of suffering depression.[35]

The melatonin synthesis also affects patients with bipolar disorder. The drugs aimed at the melatonin receptors, like ramelteon and tasimelteon, can also be an useful treatment for those who suffer bipolar disorder. The bipolar disorder is related to sleep and the mood, which is why melatonin improves the state of patients that suffer from this disease.[36]

Melatonin protects the stomach

Melatonin has a remarkable wound-healing and gastroprotective effect on gastric ulcers caused by aspirin or by Helicobacter pylori.[37]

The gastroprotective effect of melatonin is related to its benefits on the blood flow and its anti-inflammatory properties.

Clinical studies have proven that the daily use of melatonin helps to heal gastric ulcers caused by aspirin or the Helicobacter pylori bacteria. A treatment with melatonin has a higher rate of healing when compared to a regular treatment (omeprazole) to treat ulcers infected by the Helicobacter pylori.

It has also been proven that melatonin is a gastroprotector substance when it is consumed with aspirins, which can revert the development of gastric ulcers produced by aspirins.

Melatonin can heal gastric ulcers

The concentration of melatonin in the stomach tissue is a 10% higher than in blood. The concentrations of melatonin in the intestine are 400 times higher than in the brain.[38]

The melatonin that is produced in the stomach is controlled in a different way to the one that is produced in the brain. This concentration is higher at midday than at night.[39] This is due to the way the stomach reacts to the food it receives.[40] The melatonin that is produced in the stomach also controls the behavior of the intestinal bacteria.[41]

Melatonin and its precursor form, L-tryptophan, can help to heal stomach ulcers. Moreover, they protect against the injuries caused by the consumption of aspirin and infections of Helicobacter pylori bacteria. The administration of melatonin also accelerates the healing of the ulcer.[42]

Melatonin, the sleep hormone, strengthens the intestinal barrier by reducing oxidative stress up to an 88%.[43] The prevention of gastric damage caused by stress depends on the dose and efficacy of the medicines that treat stomach ulcers, like ranitidine and omeprazole. Clinical studies on mice have proven that melatonin reduced the amount of free radicals in an 88%.

The antioxidant properties of melatonin help to stop the inflammation in the stomach and protect against diseases like colitis, irritable bowel syndrome, and even several types of cancer.[42]

Melatonin also helps to prevent the death of the cells from the stomach mucosa caused by an intoxication.[44]

In a study performed on mice that suffered gastric stress, it was proved that a melatonin treatment for a week improved the state of the gastric mucosa cells.[45]

Moreover, melatonin also calms stomach pain in patients that suffer irritable bowel syndrome.[46]

Melatonin helps with the treatment of the gastroesophageal reflux disease (GERD)

The gastroesophageal reflux disease (GERD) is also known as acid reflux. This pathology happens when the stomach acid and its content go up the esophagus. The main symptoms are stomach acidity, nausea, chest pain, and eructation.[47]

A study carried out on 36 patients that suffered GERD proved that melatonin supplements reduced the symptoms of this disorder. Melatonin reduces the esophagus pressure and prevents the irritation and injuries on the esophagus when it is used alone or combined with omeprazole.[47]

However, omeprazol provided better results when it was administered alone than when combined with melatonin. Even though melatonin can treat the GERD symptoms, it is not the best choice to treat acid reflux.[47]

Melatonin and mental disorders

The main effect of melatonin consists on maintaining the biological rhythm, favoring the synchronization and stabilization of different organic processes.

There is more and more evidence that points to the fact that the interruption of the biological rhythms can trigger different mental disorders, like depression, bipolar disorder, and seasonal depression.

Nowadays, there are research lines that are studying the effects of light therapy to restore the sleep-wake cycle in patients with serious mental diseases, like depression.

The purpose of light therapy is to increase the production of melatonin, which could improve the circadian rhythm and the brain function in people with mental problems.

To put it briefly, melatonin technically provides a new way to treat these diseases by regulating the sleep-wake cycle. Therefore, the effects of melatonin to treat depression and other mental disorders are being treated.

Melatonin and anti-aging

When we grow old our health deteriorates and melatonin starts to drop. Oxidative stress contributes to the aging process. The antioxidant properties of melatonin can help to stop the oxidative damage. Due to its antioxidant properties, melatonin helps to reduces the signs of aging.

Melatonin neutralizes the reactice oxygen species (ROS) which play an essential role in the aging process caused by the free radicals. These harmful ROS are highly reactive compounds that can damage a series of important biological structure in the cells of the body.

Melatonin the elderly

The aging process is related to the onset of many diseases, like cancer, arthritis, neurodegeneration and diabetes. All these pathologies are related to the damage caused by oxidative stress.

Melatonin has properties to neutralize the ROS, which directly counters the damage of the free radicals. Moreover, melatonin also has indirect antioxidant properties for our health, since it increases the activity of several antioxidant enzymes, like the superoxide dismutase.

The superoxide dismatase plays a crucial role in defending the cells against harmful effects of the oxygen radicals, and its activation contributes to suppressing cell damage.

On the other hand, the skin produces its own melatonin which means that taking melatonin supplements also avoids the premature aging of the skin. Melatonin also protects the skin from environmental damage, like the one caused by the UV rays.

Melatonin protects against skin aging produced by the ultraviolet rays. The antioxidant effects of melatonin through topical uses favors the state of the skin. However, oral administration is not too effective for the skin.

The use of melatonin dietary supplements helped to stop bone loss related to aging in old mice. The intake of supplements managed to increase the volume and rigidity of the bone, which improved bone health.

Melatonin and the immune system

Melatonin has a powerful antioxidant effect and it helps to stimulate the immune system. In a scientific review from 2013, melatonin was called “immune buffer” because it tends to act as an stimulant under immunosuppressive conditions. Moreover, it also works as an anti-inflammatory compound that improves the immune response, like it happens in cases of acute inflammation.[8]

Melatonin reduces the inflammation and favors the health of the immune system

The melatonin receptors are present in several immune cells.[8] Melatonin is an immunomodulator, which means that it reduces an excessive immune function in inflammatory conditions and it improves the immune function in immunocompromised individuals.

Melatonin lowers the production of inflammatory cytokines, including IL-6, IL-8 and TNF-alpha.[48]

Moreover, melatonin can minimize the inflammation of the brain by reducing NF-kB and the free radicals in the microglia (immune cells which are specific in the brain).[49]

Melatonin stimulates a healthy immune response in human beings and rodents, by protecting the immune system from aging, steroid medicines, plumb, and chemical exposure.[8]

Melatonin relieves the fibromyalgia and chronic pain

The symptoms of fibromyalgia include generalized pain in the muscles and the connective tissue without any specific cause that lasts for long. A random, placebo controlled study performed on 101 patients with fibromyalgia focused on the efficacy of melatonin to reduce the symptoms of the disease.

It was observed that the symptoms considerably decreased just by taking a combined dose of melatonin with the antidepressant fluotexine (Prozac).
A group was given a daily dose of 5mg of melatonin, while the other group was given 3 milligrams of melatonin and 20 milligrams of the antidepressant medicine.[50]

Other clinical studies pointed out that melatonin could also help to lower other type of chronic pain, like the one caused by migraines.

Melatonin protects the heart

Clinical studies have shown that melatonin protects the heart. More specifically, the research reveals that melatonin has anti-inflammatory and antioxidant properties, which reduce the heart problems.[17]

Melatonin also helps to reduce the blood pressure, high cholesterol, the harmful effects of the free radicals, and it also has cardioprotective properties. In general, melatonin helps to lower the risk of suffering cardiovascular diseases, like heart attacks or strokes.[51]

Melatonin and apoplexy

A study performed in a laboratory with mice showed that melatonin inhibits the release of cytochrome C (a substance that causes cell death and damages the BAD and BAX cells) (R).

Another study with mice focused on strokes and showed that melatonin also blocks the activity of inflammatory cytokines IL-1β y TNF-α, and proteins that cause death of BAD and BAX cells (R). These proteins trigger the inflammation and the death of nerve cells when the artery that leads to the brain is blocked.

Melatonin lowers blood pressure

Melatonin plays a decisive role in the regulation of blood pressure. The activation of the MT1 and MT2 receptors dilates the blood vessels, which lowers blood pressure.[52]

Blood pressure, like sleep, has a circadian rhythm. It increases in the morning and drops at night, like it happens with melatonin. This suggests that there might be a link between melatonin and blood pressure.[52]Moreover, certain types of hypertension are due to a melatonin deficiency.[52]

Patients with type 2 diabetes managed to lower their blood pressure by taking 5 mg of melatonin. However, there is not enough information about the way in which melatonin lowers blood pressure, which means that we cannot know how effective it can be as a treatment to lower blood pressure. In spite of this, it has proven to be effective as a support treatment in hypertensive patients.[53]

Melatonin and tinnitus

Tinnitus is the name of certain inexplicable sounds that affect many people, like old people, hearing impaired people, or patients that are using certain medicines.[54][55]

Clinical studies have proven that melatonin is 150 times more effective than other medicines to treat tinnitus and reduce its symptoms.[55]

In old patients with tinnitus, the melatonin level is very low. This can point that these values are related to the activity of the ears.[54]

Melatonin and the eyes

The cells of the eye, specially the retina, produce melatonin.[56] The light affects the production of melatonin, and the cells that are sensitive to the light produce melatonin. The more light there is, the less melatonin is produced in the eye.[57]

The interruption of MT receptors produces the death of the condyle cells, which is what helps the eyes to recognize the colors.[57]

Melatonin is also important for the normal development of the eyes. For example, mice that lack one of the melatonin receptors – MT1 – show a drop in specific visual cells that are essential for the sight.[58]

Moreover, it has been proven that human cells that produce ocular pigments are protected against cell death.[59]Melatonin and aging

Melatonin protects the nerve cells from the eyes

It has been proven that melatonin prevents the death of nerve cells in an experiment with mice focused on the inflammation of the optic nerve. The optic neuritis is a disease that causes the death of the cells in the optic nerve that are in charge of the sight.[60]

Moreover, melatonin is also beneficial for the treatment of central serous choroidopathy, a disease that affects the eyes of diabetic people.[61]

Supplementation with melatonin drops during childhood and old patients is potentially beneficial for the protection of the eyes.[62]

Melatonin and glaucoma

Melatonin reduces the pressure on the human eye. It has been proven that the elimination of the MT1 causes the death of nerve cells in mice.[63]

Disorders of the melatonin function can cause glaucoma.[64] Melatonin and 5-MCA-NAT (a molecule that is similar to melatonin) are agents that can treat glaucoma, a disease caused by an increase of pressure in the eye.[65]

Melatonin and Parkinson

The development of Parkinson’s disease alter the sleep patterns.[66] Several clinical studies have shown that melatonin improves the sleep of patients with this pathology. However, it does not improve the rest of symptoms related to this disease.[67]

Clinical studies carried on animals have proven that melatonin can prevent cell death and the brain damage that is related to it.[17]

Melatonin and Alzheimer

Melatonin helps to relieve the symptoms of Alzheimer and Parkinson in mice and rats.[68] The use of synthetic melatonin or molecules related to melatonin can unlock the nitric oxide synthase for the treatment of neuronal diseases, from a stroke to Alzheimer or Parkinson.[68]

It has been proven that old people with Alzheimer’s disease have low levels of MT1 and MT2.[69]

Melatonin prevents cell death in the neurons of mice caused by the amyloid beta25-35, a substance that produces a disease that is similar to Alzheimer.[70]

A low activity and synthesis of melatonin partly explains the alteration of sleep and the problems to process the information that is observed in Alzheimer patients.[71]

The treatment with bright light in the morning and melatonin at night for old people who suffered Alzheimer improved their quality of sleep and tranquillity in general.[72]

A similar study was performed for several years in the Netherlands that proved that the treatment with bright light and melatonin was beneficial for sleep and mental health problems.[73]

The antioxidant effect of melatonin on Alzheimer’s disease are more effective than vitamin C and they reduce the oxidative stress better than vitamin E.[17]

Melatonin protects against diabetes

Melatonin works like a clock and it changes the amount of insulin depending on the moment of the day.[74] Melatonin is very important for the insulin balance, since a disorder in this system can deactivate the cell response to insulin and glucose.[75]

It has been proven that the concentration of melatonin, both during the day and at night, are lower when compared to healthy subjects in clinical studies carried on patients and mice with type 2 diabetes.[76]

A sleepless night can trigger insulin resistance and alter the metabolism. Melatonin can solve this type of problems.[77][78][79]

It has been proven that a long-term treatment with melatonin improves the state of diabetes in the muscle, hepatic, and fatty tissues in diabetic mice.[80]

It has been discovered that melatonin protects the muscle cells against a toxin that causes insulin resistance and it improves the transport of glucose to the cells.[81]

In another study with diabetic mice, it has been proven that melatonin also helps to improve the state of the liver and its activity.[82] Moreover, it protects the cells that produce insulin in the pancreas and it also restores their function.[83]

The medicines that regulate melatonin (epifamine and melax) can improve the state of diabetes in mice.[84]

The agomelatine is an antidepressant that controls the melatonin receptors, it relieves chronic pain related to diabetes. Agomelatin also helps to low the depression in diabetic patients and to control the levels of sugar in the blood. [85][86]

A clinical study links type 2 diabetes with low melatonin

A low release of melatonin during the night is related to higher risk of developing type 2. A recent research from Brigham Hospital (BWH) has discovered that the amount of melatonin that we release while sleeping can prevent the risk of developing type 2 diabetes.

Dr. Ciaran McMullan, who participated in this study, stated: “This is the first time that someone has confirmed the link between the release of melatonin at night and the risk of suffering type 2 diabetes”. “We hope that this study will encourage further research about the release of melatonin and the role it plays in the alteration of glucose metabolism and, therefore, the risk of suffering diabetes.”

Regarding this study, the researchers identified 370 women who have developed diabetes while they participated in the Nurses Health Study, as well as another 370 women for the control group of the same age and race. When both groups were compared, the researchers discovered that the participants with a low release of melatonin at night had more chances of developing a type 2 diabetes that other participants with a high release level of melatonin at night.

The study had established other risk factors for diabetes like the body mass index, family history, and lifestyle (diet, exercise, smoking, amount of sleep). It was discovered that the release of melatonin was still an important risk factor.

Melatonin and fertility

Melatonin improves the motility of the sperm. It also helps to inhibit cell death in the sperm. It improves the quality of the spermatozoa and, therefore, it increases the fertility.[87]

Reactive oxygen species inhibit the maturing of ovocytes. But the oral administration of melatonin reduces the oxidation damage to the ovocytes and it increases the percentage of fertility.[87]

The aging process reduces the fertility. A melatonin treatment in female rats prolonged their fertility phase.[88]

The administration of melatonin (10mg / kg for 6 and 12 months) in mice also increases the quantity and quality of ovocytes. It is believed that this is due to the suppression of oxidative stress produced by melatonin.[88] However, high doses of melatonin can damage the ovocytes and embryo cells.[87]

Reactive oxygen species and oxidative damage hinder the fertility treatment. The antioxidant effect of melatonin increases the success of fertility treatments in vitro.[87]

It has been proven that the use of melatonin helps to prolong the reproductive ability in aging female mice. However, there are not enough studies in people to confirm this discovery. It is necessary to perform additional test to confirm the benefits of melatonin to preserve fertility in women.[88]

Melatonin protects the brain

Melatonin helps to reduce oxidative stress and inflammation in the brain and, moreover, it also increases the BDNF (Brain-Derived Neurotrophic Factor) and strengthens the blood-brain barrier. Due to this, its use is being studied as a treatment for several brain and neurological disorders.

Melatonin has antioxidant effects in the brain, bone marrow, optical nerve, and the soft matter of the bone marrow, and it also protects the nerve cells.[17]

Melatonin helps with the regeneration of the brain and neuroplasticity

Melatonin actives the brain-derived neurotrophic factors (BDNF), which is a protein responsible for the wellness and regeneration of nerve cells.

Melatonin and a restful sleep

Melatonin strengthens the blood-brain barrier

Melatonin strengthens the blood-brain barrier.[89] If this barrier has any leaks it can cause a cognitive dysfunction (mental confusion), Alzheimer, or disorders like anxiety or depression.

Melatonin helps to treat traumatic brain injuries

Melatonin helps to treat brain trauma.[90] Clinical tests performed with mice have proven that the treatment of a brain injury with melatonin can reduce the inflammation in several areas of the brain.[91][92]

Melatonin during menopause

It has been proven that melatonin supplements can improve the sleep alterations produced during menopause. In a study with peri-menopausal and menopausal women aged between 42 and 62, they were given a daily dose of melatonin for six months. The result was a general improvement of their mood and a marked reduction of depression.

This study suggests that melatonin supplements in peri-menopausal and menopausal women restore the hormone regulation, as well as the pituitary and thyroid function.[93]

This is a very positive result, since it proves that melatonin can reduce the symptoms of menopause as well as the sleep problems that it causes.

Melatonin relaxes the smooth muscles

Melatonin supplements help to relax the smooth muscles. Most muscle relaxants only help to relax the skeletal muscle, like the muscles from the back or shoulders, which can be controlled consciously. Melatonin relaxes the smooth muscles, which are involuntary muscles which are not under our control.

“Melatonin offers unexpected improvements for the treatment of esophageal reflux, the gastrointestinal symptoms of ulcerous colitis, cystic fibrosis, and chronic diarrhea. Therefore, it seems that melatonin has some kind of influence on the state of the gastrointestinal tract.”

One of the less known benefits of melatonin is its effect on the smooth muscle from the digestive tract. In the same way that it has proven to be good for the irritable bowel syndrome, esophageal reflux, and other problems related to irritability during the digestion, it is known that melatonin helps to relax the smooth muscle from the digestive tract.

This makes sense because melatonin is also produced in the gastrointestinal tract, apart from the pineal gland. This explains why melatonin works as an adaptation mechanism to avoid the irritability and inflammation due to stress.

Melatonin and cancer

Some scientists believe that a prolonged exposure to artificial light (light pollution) could be one of the triggers of the dramatic increase of the current rate of cancer in the Western world.

It is believed that artificial light alters the day-night rhythm and other biological processes that are naturally controlled by the biological clock. The clinical studies have proven that those people that work during the night have more chances to suffer from cancer than those who have a regular work schedule.

Nights workers are exposed to artificial light during long periods of time, and then to natural sunlight during the day.

This higher exposure to light produces an excessive secretion of melatonin that cannot be adapted to the natural rhythm of the organism. This leads to an abnormal release of melatonin that is probably the reason why this people have an increased risk of suffering cancer.

The recent studies on the effects of melatonin in tumors has revealed that melatonin can slow down the progression of the tumors. It has also been proven that melatonin produces an effect against metastasis in several types of cancerous tumor, melanomas, and leukemia.

Particularly, a clinical analysis has proven that the daily consumption of melatonin significantly reduces the mortality rate in patients with cancer tumors after a year.

The benefits of melatonin are promising, even though it is still necessary to carry out more research on its effects and safety as a therapeutic agent against cancer.

Current research on melatonin as a treatment against cancer focuses on the following issues:

  • Clinical studies on the effects of melatonin to prevent and treat breast cancer.
  • Melatonin plays an essential role in the prevention of prostate cancer and colon cancer by avoiding the proliferation and differentiation of carcinomas.
  • The effect of melatonin injections for the treatment of tumors is currently being studied.
  • The administration of melatonin helps cancer patients to tolerate chemotherapy better.

Melatonin helps to prevent and treat cancer

Melatonin plays an important role in the prevention and treatment of several types of cancer. It has been proven that patients with breast, prostate, or colorectal cancer have low melatonin when compared to healthy people.[17]

The use of melatonin has managed to block cancer tumors in cancer cells of the breasts. Thanks to this, it managed to block the estrogen receptors that caused the cancer.[94]

It has been proven that using melatonin to treat the cells increases the production of the E-cadherin protein which block cancer. Moreover, it also reduces OCT4 and N-cadherin, which help tumor cells to survive and invade other organs.[95]

Melatonin also works for the treatment of cancer stem cells. This type of cells divide without control and make the cancer more resistant to treatment. Melatonin reduces the aggressiveness of stem cells and reduces their proliferation.[95]

The anti-cancer activity of melatonin comes from its ability to improve the immune function ®. Melatonin stimulates different types of immune cells, like TH2 cells.[96][97]

In the case of mice with gastric cancer, a treatment with melatonin suppressed the activity of T cells which produce cancer.[98]

T cells block the activity of immune cells. Tumors spread with the help of T cells, which block the defense of immune system cells. Melatonin blocks the T cells and produces the death of cancer cells.[98]

It has been proven that a regular treatment with melatonin reduces the amount and size of the tumors from breast cancer.[17]

Melatonin supplements stabilize the health of patients with lung and colorectal cancer, since they reduce the tumor dissemination and increase the death of cancer cells.[17]

Melatonin perturbs the cancer cells process in cell cultures. Thanks to this, it blocks the growth of cancer cells and limits their ability to invade the organism.[99]

However, it has to be taken into account that melatonin injections can stimulate the growth of the tumor if they are administered in the morning. This is why we have to be really careful when it comes to choose the moments we administer the melatonin.[17]

Effects of melatonin

Clinical studies have proven that a low melatonin can be related to the risk of suffering breast cancer.

The researchers have studied the effect of melatonin on the growth of breast cancer tumors in vitro (using human cells cancers) and live (using mice) in order to measure its efficacy to suppress the growth of the tumor.[100]

In this research they found out that melatonin inhibits the growth of the tumor and the proliferation of cancer cells, as well as the formation of new blood vessels in breast cancer with negative estrogen receptors. This study carried out on 2014 shows the great potential of melatonin to treat breast cancer.

Another study proved that women who took the tamoxifen medication which is used as chemotherapy against breast cancer did not experience any kind of improvement. However, a 28% of the women improved lightly by including melatonin in their treatment.[101]

The studies have also proven that men with prostate cancer have lower melatonin levels than healthy men. In a study published in the Journal “Oncology Reports”, it was analyzed if melatonin could alter the growth of androgen-dependents prostate tumors cells. The results proved that melatonin is capable of inhibiting the propagation of prostate cancer cells.[102]

Together, these studies show the great potential of melatonin as a natural and complementary treatment against cancer.

How to take Melatonin? Dose of melatonin for adults

Melatonin is available in tablets, capsules, drops, or sublingual tablets. Depending on the age and type of treatment, it can be administered in doses from 0.5 to 10mg daily.

The benefits of melatonin have been studied in depth and the results have proven that it helps to combat insomnia at any age, from children to adults. However, it seems that it works differently depending on the dose, and a higher dose does not necessarily provide more benefits to fight insomnia.

The dose of melatonin is not different for adults or the elderly. If it is used to sleep a dose from 0.1 to 20mg will be enough to reestablish the sleep patterns.

A clinical study found out that a dose of 0.1mg, a tenth part of a milligram, could improve sleep problems. They compared these melatonin levels in the blood with that of healthy people without issues of this kind and they discovered that such a low dose was not only effective to sleep, but it also increased the melatonin levels in the blood, matching those of healthy people without sleep problems.Melatonin supplementation

In fact, when melatonin was discovered by MIT scientists, the university patented a dose between 0.3 and 1mg because they never though that people would take a dose three times higher than the “physiological dose” of 0.3mg. Ironically, to elude this patent, other companies started to produce higher doses. Therefore, we have to be aware of the fact that a higher dose is not necessarily better, but that these high doses have been manufactured due to commercial reasons.

  • Remember: melatonin is a hormone. When we take hormones, instead of using the ones we produce, the body performs a biofeedback cycle which frequently lowers their production. This is the reason why it is not a good idea to take a higher amount than that of the effective dose which, in the case of melatonin, tends to be better in low amounts.

A higher dose of melatonin is not only not better, but it can be even worse. The recommended dose moves between 0.1 mg and 0.3 mg. In a study performed on old people with sleep disorders, it was proven that a dose of 0.3 mg (equal to 300mcg of melatonin) improved the quality of sleep significantly. However, a dose of 3mg, around 10 times higher, was not effective at all.

In another study, a blind person with sleep problems could not improve the sleep cycle by taking 10 mg of melatonin, while the rest members of the study with the same problem improved their quality of sleep with a dose of 0.5 mg.

This means that a little dose of melatonin between 01 mg to 3 mg is generally more effective than a higher dose. Even though these is practically no reason to worry about a melatonin overdose or addiction, higher doses are unnecessary and even ineffective.

Melatonin for Jet Lag: in this case, the clinical studies advise an oral dose of 0.5 to 6 milligrams of melatonin, an hour before sleeping in the final destination. Another choice would be to take from one to five milligrams before going to sleep two days before traveling and another two or three days after reaching the destination.

In the case of sleep biorhythm disorders in people with and without sight problems: it is advisable to take a single dose from 0.5 to 5 milligrams before going to sleep or a daily dose of that amount for one to three months.

For a delayed sleep phase syndrome: it is advisable to take a dose from 0.3 to 6 milligrams orally (5 milligrams daily) every day before going to sleep for a period of two weeks to three months.

There are many more suggestions when it comes to dosing melatonin depending on the diverse health problems based on scientific research, the traditional use, and advise from the experts.[103]

Take it around 30 minutes before going to sleep.

When should I take melatonin?

It should always be taken at night without exception, around half an hour before going to sleep, since melatonin is a hormone that is naturally produced in the body during the night to encourage sleep.

Melatonin produces tiredness, because that is precisely the effect it is supposed to cause. Therefore, tiredness is not a side effect, like some people think. If you are taken melatonin, get ready to sleep and use it only before going to sleep. In this way, you will be able to sleep for 8 complete hours.

Who can benefit from melatonin?

Melatonin supplements are advised specially during periods of insomnia, which is either produced by stress or other factors like:

  • Split work schedules or different timetables.
  • Jet Lag.
  • Chronic insomnia or difficulty to fall asleep.
  • It helps to regulate the sleep-wake cycle in blind people.

Avoid the following mistakes when using melatonin:

  • When we use melatonin to sleep better, some people use a tablet too early and if they see that it does not work, they take another one.
  • Some people wake up in the middle of the night and take another dose. Even this does not cause serious problems, this is not the right nor the safest way to take melatonin because, the higher the dose, the higher the chances of experiencing unwanted side effects, like feeling tired in the morning.

Important: if you suffer cancer, you should always consult your doctor before taking melatonin. Your doctor will know better than anybody else how to advise you and to follow your progress.

Do high doses of melatonin have contraindications?

Different doses of melatonin have different effects. A clinical study that used very high doses of melatonin, even 300 mg daily for several months, and a dose of 75 mg for 3 years, concluded that high melatonin doses do not cause any problem.

Low doses of melatonin are more effective

It is advisable to take the lowest dose possible with a formulation of immediate release for adults should be around 0.3 mg and up to 1 or 2 mg, preferably one hour before going to sleep. This method imitates the physiological circadian rhythm of melatonin and avoids a long duration of melatonin with levels over the physiological level in the blood.

Moreover, it has also been proven that higher doses of melatonin orally cause high melatonin levels during the day. A clinical study proved that a higher dose in a prolonged release formulation of a 75% (4 mg) caused a significant prolongation of the increase of melatonin levels in the morning and during the day when compared to a lower dose (0.4 mg).

Higher melatonin doses entail a risk of prolonging the physiological levels in old adults during the following day. This could produce problems with side effects like dizziness, somnolence, restlessness after waking up, in spite of the low toxicity of melatonin.[104]

The studies also analyzed the additional effects of melatonin administration in other results, like sleep and body temperature. It was proven that the melatonin that was consumed orally had a positive effect on sleep parameters. Some studies have also proven that the highest doses and the prolongation of physiological levels can make melatonin ineffective.

Is it advisable to give melatonin to children?

The melatonin that is naturally produced is completely safe but, is it advisable to give melatonin supplements to small kids?

Most of them produce enough melatonin and they do not need to take additional melatonin in general. But there are some who cannot produce enough melatonin and the clinical studies show how some of them who suffer determined diseases can benefit from melatonin.

Even though there are few “double blind placebo controlled” studies, there are lots of “open” and “crossed” studies about the benefits of taking melatonin for children with some of these problems:

  • Growth disorders
  • Autism
  • Neurological problems
  • Attention Deficit Hyperactivity Disorder
  • Asperger syndrome
  • Serious sleep disorders
  • Blindness
  • Brain Paralysis

Its use for cases of fibromyalgia has not been studied but, since one of the typical symptoms of fibromyalgia is a sleep / wake cycle disorders, it could also be effective in these cases.

There are several studies about the effects of melatonin in children. In most of the cases, it has been proven that melatonin is effective for the treatment of sleep disorders, with few or any side effect at all. So much so that even they have been given high doses of melatonin. It has also been proven that melatonin is beneficial for newborns who are critically sick and who need assisted ventilation. All of this proves that melatonin is safe for kids.

Dose of melatonin in children

A dose of melatonin from 1 to 6 mg per night was used in most studies with melatonin. But some studies with adults and reports of melatonin for kids show that with just 0.1mg (1/10 of a milligram) the dose is as effective and causes less problems of morning somnolence or nightmares.

As I said before, the studies reveal that the highest doses are ineffective, while the lowest doses are more effective. Even though it is impossible to suffer a melatonin overdose, it is always advisable to administer lower doses of melatonin to children and always at night, just before going to bed.

In general, melatonin is an effective treatment for them and it is quite safe to treat sleep disorders, regardless of their cause. Moreover, those who have digestive problems have improved when it comes to the relaxation of the smooth muscle that intervenes in the digestion.

Side effects of melatonin for children

One of the side effects of melatonin is morning somnolence. Moreover, a little number of children suffered temporary headaches, nightmares, or mild enuresis.

There have been very few reports about problems related to the consumption of melatonin by children. Thousands of autistic children with sleep disorders have taken melatonin supplements to sleep for long periods of time without any issue.

Is melatonin safe in children who suffer convulsions?

There is a clinical study performed in disabled children in which one of them suffered an attack after taking melatonin, which is why doctors do not advise its administration in these cases.

In spite of this, there are other studies that have gathered cases in which the children with convulsions improved their state after taking melatonin. There was one case of a child with serious convulsions who improved when he was treated with melatonin.

This is why the new studies suggest that, even though there was just one case of a child who had problems, melatonin is beneficial for children with convulsions in most of the cases.

In any case, there is no reason to not give melatonin to a child that suffers insomnia just because he/she has a convulsive disorders or because we fear that we may trigger an attack. There seems to be little or no justification for this warning when thousands of autistic or disabled children use it safely each year.

However, high doses of melatonin can trigger convulsions in young people. It also interferes with growth during puberty due to its possible effects on the hormones. Therefore, it is advisable to always consult a doctor before giving melatonin to children.

Melatonin and autistic children

The research has proven that melatonin can help children with growth problems, like those who suffer autism. This is specially important since autism is considerably increasing.

A scientific evaluation from 2011 published in the “Developmental Medicine and Child Neurology” evaluated 35 studies related with the effects of melatonin on disorders from the autistic spectrum, including autism, Asperger’s syndrome, Rett’s syndrome, and other common causes of growth disorders.

After reviewing all the studies, the researchers concluded that the use of melatonin supplements for autistic spectrum disorders results in better sleep parameters, improved behavior during the day, and minimal side effects.[105]

Side Effects of melatonin

There are few people who have problems with melatonin, to the point that it is even administered to seriously sick children, newborns, and autistic children. Even though there is a lot of people who take melatonin in the world, the reports about some side effects are quite scarce.

Melatonin is quite safe if it is taken for a short period of time. For some people is also safe, even when it is consumed for long. Melatonin can be taken without any problems for a period of up to two years.

Melatonin has a low toxicity and it is generally well tolerated. However, the most sensitive ones can experience the following side effects:

  • Dreams or nightmares
  • Headaches
  • Dizziness
  • Daytime somnolence
  • Short-term depression
  • Stomach cramps
  • Irritability
  • Low libido
  • Pregnant or lactating women should not take melatonin. Melatonin is a hormone, which is why those who have or have had any hormone health problem should only use melatonin under medical supervision
  • You cannot drive any vehicle or machine five hours after consuming melatonin
  • If you accidentally consume a melatonin overdose, you should look for medical help immediately

Morning somnolence

One of the most frequent side effects of melatonin is a feeling of tiredness in the morning which can be more pronounced with high doses. It is not a symptom of an overdose, since it is extremely hard to cause a melatonin overdose. In fact, those who have tried to cause a melatonin dose have failed. There are clinical studies that administered up to 6 grams of melatonin daily for 30 days without observing any symptom of an overdose.

If you are too tired to go to sleep after taking melatonin, you should take these two things into account:

      1. Make sure that you sleep for 8 complete hours: most people complain about feeling tired the following morning because they did not sleep for 8 complete hours. It is logical to be tired in the morning if you have taken melatonin to help you sleep and you have not slept during the night.
      2. Take a lower dose of melatonin: some studies have proven that a lower dose of melatonin can work better than higher doses. The average dose goes from 1 to 3 milligrams. But even just a 0.1 milligram is effective to help people to sleep. For some, the lowest dose is more useful to sleep and produces less tiredness in the morning.

Somnolence and fatigue

Since melatonin is a sleep enhancer, the most common thing is to experience somnolence. Even though this is more an effect than a side effect, some people complain about it and they often interpret it as tiredness when it is just somnolence.

Melatonin should always be used at night, because that is the moment when the body normally produces it. Moreover, since it helps people to fall asleep, that is precisely the moment when it should be taken.

A lot of people complain about an excess of sleep in the morning, this specially happens to those who suffer chronic sleep deprivation who are finally able to sleep again. If you manage to sleep but to feel extremely tired throughout the day, no matter how much you sleep, this is called “hypersomnolence”.

If you experience hypersomnolence you should stop taking melatonin until you have a few free days and take it before going to sleep on the weekends, so that you can sleep most of the weekend.

If you do not feel better after this, stop taking melatonin and repeat the process the next weekend.

This happens because your body has accumulated a lot of sleep for a long time, and it can take a month or two until it achieves a normal sleep pattern.

If you see this as a cure and not as a side effect of melatonin, it will be easier for you to fix it. Hypersomnolence is not problem once you know what it is and how to control it. In fact, it is a necessary process to recover sleep in those people who have suffered chronic insomnia.

Low sex drive

There is a very tiny percentage of people who have complained about a reduce sex drive and, curiously, infertility. The reason under the low sex drive is related to a bad administration of melatonin in terms of the time of the day, to hypersomnolence, or a very high dose of melatonin.

The problem can be tiredness and somnolence instead of a low libido. If the hypersomnolence disappears, then the sex drive will come back.

However, one of the most interesting side effects of melatonin is a change in the hormone balance that can produce infertility in men and women when it is consumed in massive doses.

This may look like an undesirable side effect, but the fact that high melatonin levels produce a predictable and reversible response response has been used for some to try and create a natural and safe contraceptive for women.Melatonin and pregnancy

Is melatonin safe?

The safety of this substance is very well documented. During the last decade, melatonin has been widely used as a supplement. In all this time, there have not been practically any problems due to the side effects of melatonin, even when it has been consumed in extremely high doses!

If you have any doubt as to how much melatonin you should take, we advise that you always consult your doctor, he or she will know which dose will be more suitable for you since he or she will be up to date with the latest news and studies about melatonin.

It has been proven that a melatonin overdose is almost impossible, even if it is consumed by children.

In fact, it is extremely difficult to poison someone with melatonin. Scientists have tried to produce a melatonin toxicity in mice but they have not succeeded.

The scientists who carry out preliminary studies about substances to determine toxicity levels have developed a number called LD50. This is the dose that consistently kills half of the mice that were given a determined substance.

However, in the case of melatonin, the scientists have not managed to produce a concentration that will kill a mouse. This means that melatonin does not have LD50, regardless of the dose.

When scientists administered 6 grams (6.000mg) of melatonin to study subjects every night throughout a month, the only side effects were stomach discomfort and residual somnolence.

There is a report about three people who tried to commit suicide by taking a melatonin overdose. 2 of them took 20 tablets of 3 milligrams each, and the other 50 tablets of 3 milligrams each. In spite of this, non of them succeeded, they were fine after taking the tablets, they barely experienced any side effects or strange symptoms, and they did not need medical treatment.

Those who tried to commit suicide took a lower dose than the daily dose administered to volunteers in different clinical tests.

For example, several women were given 300 mg every day for 4 months. There were no issues whatsoever.

In another study, several people were given a gram of melatonin (1000 milligrams), every day without any issue. In another study, the participants were given 6 grams (6.000 milligrams) every day for a months and the only effect was a little bit of morning somnolence.

How can we combine Melatonin?

Melatonin can be perfectly combined with sleeping supplements which help to control stress, reduce the anxiety, and favor a state of calmness and wellness.

If our objective is to achieve a more restful sleep, it will be useful to combine Melatonin with:

Studies and references about Melatonin

      • 1. 1 in 3 adults don’t get enough sleep. Centers for Disease Control and Prevention
      • 2. Melatonin. Memorial Sloan Kettering Cancer Center
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