Melatonin: Contraindications, Properties And Benefits

There are factors that intervene in the stimulation or inhibition of hormones , such as: nutrient levels in the body, neuronal activity, mental state, including the interference of other hormones. Also as in the case of melatonin; Environmental factors influence, from temperature, to natural light.

Biologically, all living beings are composed of different chemical substances naturally, produced by our own organisms in order to regulate high-need biological activities, for the optimal development of this and the maintenance of life.

These substances are known under the name of hormones ; elements secreted by certain glands or specific cells in human beings, plants or animals, their transport is through the bloodstream, they are also transported by sap; depending on the type of living being referred to, their importance lies in the regulatory function they have. Let’s talk about melatonin.

What is Melatonin?

The melatonin , also known under the scientific name N-acetyl-5-methoxytryptamine , is a hormone secreted primarily in the pineal gland and brain pituitary (located in the hypothalamus) whose functionality is very diverse, as part of various processes cell phones.

This hormone can be found in living beings such as animals, whether terrestrial or aquatic, plants, humans and even evidence of melatonin has been seen in   bacteria, fungi and certain algae , all with different levels of concentration, thanks to the daytime / night that governs that living being throughout the twenty-four hours of the day.

The effective and immediate response of this hormone to environmental changes in lighting is incredible, which is why it tends to be considered a neuro-hormone because it is found in the influence of the suprachiasmatic nucleus originating in the hypothalamus. That is, thanks to the retina it can absorb information about the regular patterns that determine light and darkness.

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Likewise, belonging to neuroendocrine or neurophysiological processes, with the important ability to regulate the daily sleep cycle; either naturally or synthesized by an essential amino acid such as tryptophan.

Another characteristic that this hormone possesses is the variability of the synthesis of said hormone throughout a 24-hour cycle, that is, it is guided by the light patterns it receives throughout a day. For this reason, it is called a neuro-hormone because it also helps the retina to guide itself through changes in light and dark.

The first signs of Melatonin

Initially, the clarification in the skin of the toad was studied with small portions of concentrations extracted from the pineal gland. However, it was not until later, in the 1950s, that the pineal hormone, melatonin , was isolated through pinealocytes from cattle or cattle. Its name is based on its chemical description.

As on many occasions, knowledge about this hormone changed over time, first it was believed that it was generated in the brain sector; However, later studies revealed that it can be generated in other parts of the body such as the liver, retina, ovaries, kidneys, and even in other thyroid or adrenal glands.

They have been produced in the same way, which reveal variations in melatonin levels due to age, enriching themselves in adolescence and suffering a decrease around thirty, which could be observed in the stage of Homo sapiens.

How is melatonin released?

The release of the hormone can occur as a process of photoreception or phototransduction , depending on the organism, stimulated thanks to the darkness that is present around it. This is due to nerve signals that are sent from the eye to the retinohypothalamic tract, where it passes through the suprachiasmatic nucleus.

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From there, it proceeds to exit through the spinal cord to a cervical ganglion, to end its journey in the pineal gland, where the hormone is produced. This process is only valid for some phototransduction entities. In fish, birds, and some reptiles it is only a photoreceptive process.

All the aforementioned promotes that melatonin, under normal circumstances, tends to fall during the daytime as a reflection of light and rise rapidly at night due to the absence of ambient lighting. Hence, it is also called ” hormone of the night .”

Factors that influence its secretion

There are certain factors that affect or help to modulate the secretion of melatonin , there are two types of groupings:

  1. Environmental: affects according to the environment in which the organism is located, the conditions that surround it and the way in which it is perceived as the photoperiod, temperature, periods of the year and lighting.
  2. Endogenous: they are based on the internal development of the individual such as their emotional state or their age, stress levels can cause secretion disorders.

In the same way, the way in which the hormone is secreted varies according to the entity, giving way to three types:

  1. In a rodent of the Cricetidae family, it tends to present a sharp end in the serosity pattern.
  2. Whereas, in humans it presents with a progressive increase until reaching a maximum secretion.
  3. In the case of sheep, with a successive accentuation up to the maximum and a time in that stage and then decrease again.

Melatonin hormone function

Over time, various functions that the hormone possesses have been discovered, although some are still the subject of studies to be certain of the results generated. The main function is to regulate the sleep cycle in organisms , even single-celled, controlling the biological clock under the regime of circadian rhythms.

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Taking into account the photoperiods that each living being has. We cannot equate the photoperiocity of a bear, which hibernates, with that of us human beings; because normally, we have more exact times of sleep, so to speak. Melatonin is a way for the body to measure time and inform itself about what time it is.

Reason why, it induces energy and activity in the day to diurnal organisms and inhibits it in nocturnal subjects at the same time; The same can happen in the opposite way, of course. Improving the state and frequency of sleep by those who experience it.

Among other functions, it has been discovered that the secretion of this hormone in the female reproductive gonad, the ovaries, creates a neuroendocrine-reproductive interrelation, studies have revealed that the synthesized administration of this hormone in peri-menopausal women helps to reverse evident effects of the menopause .

Effects such as hypothyroidism or other kinds of thyroid dysfunctions, as well as difficult fertility, the imminent withdrawal of the menstrual cycle and mental or emotional problems presented at that stage of development that affects the female population are improved, since the arrival of this one.

Research has also been carried out, in animals, above all, that demonstrate the importance of the receptors presented in melatonin for the functionality of the long-term learning mechanism, since it has an altering function in electrophysiological processes related to memory and their interaction.

Among other functions, there is the maintenance of the state of youth, that is, melatonin intervenes in the aging process , if there is a decrease in the hormone, this process generally ends up being accelerated. It also acts as a firewall and stimulator of the immune system, it also protects the cardiovascular system.

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In certain organisms, it has a reductive action of damage to tissues of the heart as well as of the brain due to ischemia, however, this fact has not been proven in humans. What has been proven is the enrichment of (GH), better known as: growth hormone .

Which is why melatonin is today a widely recognized and studied hormone, since it interacts in vital biological processes for the development of life, in different sectors of the body.

Other studies done on Melatonin

Melatonin, based on its different functions, can offer a variety of treatments for a variety of diseases and conditions, so experts carry out research, in order to find a cure or stabilizer for any of them, here are some studies carried out:

Neurodegenerative diseases

Synthesized melatonin can be considered a pharmacological medicine that could be the answer for diseases such as Alzheimer’s , Parkinson’s , Huntington’s disease and even amyotrophic lateral sclerosis , this being the base hormone for a therapeutic treatment that helps prevent death or degeneration of neurons.

This is because this hormone inhibits the addition of a certain protein ( beta-amyloid ) to certain neurotoxic aggregates that cause neurotoxicity in it, being the origin of the death or deterioration of neurons, which are the main causes of the diseases mentioned above. .

Unfortunately, very few studies have been carried out in this field and, given the lack of material and methodology, only the approach described above has been made of them, and it cannot be taken with all veracity, since they have not been able to be confirmed to use the use of the hormone in the treatment of pathologies.

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Investigations can be seen on the effect that the hormone can have in terms of achieving stability in patients with delusions, even positive results were observed on several occasions in elderly people exposed to the use of melatonin to calm their condition, not achieving a cure , but it does alleviate the symptom.

Similar to the previous study, the use of the hormone for this condition cannot be confirmed in itself, due to the lack of more patients and better studies that can affirm this approach.


Apparently, research shows that given the function of the hormone before the improvement of the learning mechanisms according to the term it has , helping in a better conditioning of the memory; It is also found to counteract one of the side effects, caused by methylphenidate, which causes insomnia in most patients.

Likewise, it is observed how lack of sleep does not help people with this disorder, so the use of the hormone helps in a better development of the individual and promotes a stimulation of a better mood of the patient.


As in other studies, there is not enough information to determine that using melatonin as a preventive drug for some kinds of headaches can be effective, however, medical trials have been found that describe this use as encouraging to treat mainly headaches. cluster or the very well known migraines .

Similarly, recommending the hormone as a medicine for these symptoms cannot be considered until there is more research to promote and support its use in this type of problem.

Psychiatric conditions

Also known under the name of psychological or mood disorders , a great diversity of them can be found, affecting the behavior, thinking and emotions of the individual who suffers them.

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Some studies have come to see how melatonin has had effective results in its use for disorders of this type, some known as depression or bipolar disorder, it has even been considered as a treatment for circadian disorders.

Although it may not seem like it, by the year 1895 it was observed that bipolarity could produce greater sensitivity towards light, which causes the body to not be able to differentiate lighting; in turn, a decrease in the production of melatonin occurs in response to night light.


There are several contradictions in this, some studies suggest that the hormone can be used as a therapeutic treatment against the disease, others promote that there are not enough justifications regarding this issue. However, third studies indicate that using melatonin can lower the death rate from certain types of cancer.


It has been seen that melatonin concentrations are higher in the bile than in the blood streams themselves. Trials suggest that the existence of this hormone in bile may be vital in the prevention of damaged tissues in the bile ducts or the digestive system, specifically, the small intestine, thanks to the acids that bile is composed of.


Experimental investigations carried out in animals have shown that melatonin has properties that interfere in the transformation of white fat to one another class of fat tissue, such as brown fat, responsible for the generation of heat as a response action of metabolism.

The experiment revealed that administering melatonin additives in sterilized water rations can have the effect of losing weight and fat in the abdomen of rats observed in laboratories. What is surprising is that this loss did not force the animals to consume lesser amounts of food or more physical labor.

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It should be noted that for safety reasons it is not recommended under any circumstances to use the hormone to lose weight, despite the success of the research; since we must take into account the great differences between the organism of human beings and animals.

Radiation protection

Based on human and animal studies, it can be said that melatonin has a protective function against radiation , perhaps even more effective than components such as amifostine , since it has the ability to counteract damage caused by highly reactive substances, called free radicals .

These radicals are molecules without stability that can introduce oxygen to the cells, they give rise to ionizing radiation, which not only causes damage to cells, but also to DNA and proteins; therefore, melatonin is suggested as a treatment to prevent such deterioration, also due to its easy and safe intake.

Melatonin and its medical use

Despite all the medical benefits that this hormone could provide us according to a wide variety of studies, medically it has only been accepted to be administered as a medicine to treat primary insomnia , for short periods and in patients whose age exceeds 55 years.

There are contradictions in this area, since research projects assure the little vigorous functionality that the hormone presents as a treatment for sleep disorders , however, it admits that it effectively and safely increases the time that the individual dreams and suffers from insufficiency at time to sleep or dream.

What would be the recommended dose?

First of all, it is recommended that to take it it is prescribed by your usual doctor or the person’s taste, although they distribute the synthesized hormone without the need for a prescription; the important thing is that an expert prescribes the intake of the hormone, because like any treatment, it can have counterproductive results.

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The normal thing would be to take a dose of between 1 or 5mg, enough to raise the levels of the hormone in the blood in excess , it is necessary that the person when taking the melatonin is fully aware of the time to ingest it. Otherwise, it can make the sleep deficiency worse instead of improving it, or end up affecting your mood.

Benefits of its use

We must know that synthesized melatonin has a purity of 99%, this makes it a better option than using sleeping pills, which can be dangerous and addictive. Among other benefits we can mention:

  • Ensures sleep regulation.
  • It gives greater quality and realism when dreaming.
  • Helps with lethargy.
  • Promotes performance when getting up.
  • Reduces the frequency of sleeplessness at night.
  • Adjust the biological clock.

Natural method to increase melatonin

Food is a natural and healthy method to enrich the levels of melatonin in the bloodstream , taking into account that it can be synthesized due to tryptophan; eating foods rich in this is a very good idea. It is also said that vitamin B6 helps in increasing the secretion of the hormone, some foods with high concentrations of this vitamin are:

  • Dried herbs and spices.
  • Raw garlic
  • Liver.

On the other hand, foods that we can eat to sustain or raise levels of this hormone are:

  • Banana.
  • Corn.

When it comes to having sleep deficiencies we can add some foods to our eating routine , in addition to improving our sleep style and of course our health. The three most recommended foods for their concentrations are rice, oats and corn.

Side effects and contraindications

It is essential to clarify that it has its pros and cons, the use of melatonin can have unwanted effects , we must be clear that it is a hormone that not only has regulatory activity on sleep, but also with respect to other vital cellular processes. These effects can be:

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  • Headaches.
  • Sickness.
  • Slight tremors
  • Depression.
  • Hypotension
  • Colic.

Reason why people with these characteristics must have medical permission to ingest it:

  • Newly born.
  • Diabetics

Neither should it be ingested by people with the following conditions:

  • Depression.
  • Clotting problems
  • Transplant recipients.
  • Presence of bleeding or seizures.

There are some very relevant calls for attention when it comes to ingesting the hormone ; it should not be handled under any circumstances, as it can cause lethargy and may have major consequences.

Take prevention, if the person is under any treatment, it is necessary to ask your GP if taking melatonin does not interfere or can bring worse and unwanted consequences. For example: a person on medication for blood pressure problems should not ingest this hormone.

Likewise, certain plants are present for medicinal purposes or supplements that should not be mixed with the hormone either, such as: caffeine, any herb or compound that delays clotting, neither for seizures or as a sedative.

Melatonin and children

The administration of this hormone in children must be carried out under strict medical supervision, since it can alter the normal pattern and architecture of the body; Likewise, it is recommended by the “Spanish Society of Pediatrics” and the “Spanish Sleep Society”, this study was carried out by the popularization of this compound as a vitamin supplement.

Melatonin is a chronobiological agent, effective and well tolerated in adult organisms, where it has been commonly used to treat bone problems and strengthen this system, it has also been used for the regularization of immunity , vascular problems in arteries and vessels .

It is believed that it can have advantageous effects if it is given in children , especially if it is to regulate the pattern and structure of sleep; However, due to the few studies that have been carried out, the safety of this in the child’s body cannot be verified, since these investigations were carried out for very short periods of time.

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Due to the lack of knowledge of the side effects, it was determined that it is not safe to medicate melatonin in a child unless the case warrants it due to its severity, however, these investigations were able to obtain very positive results in such cases, determining the factors where it can be applied and the age.

In children under 6 months of age, for no reason should it be used until the infant is 1 year or 12 months old, for reasons of safety and tolerance in the body.

Melatonin in 12-month-old children has been shown to be effective in regulating the circadian rhythm of sleep, but medium and long-term side effects are unknown . If you are going to use this drug, its administration cannot last more than 4 weeks.

In children aged 1 to 3 years, the same happens as in children according to the case shown above, that is, its administration can be risky, for this reason the decision is entirely at the discretion of the specialist.

However, with children older than 3 years, the results were very positive as a sleep regulating mechanism, and no series of side effects were verified during the 3 years that elapsed, after having finished the treatment, but there are no related data for a longer time.

However, doctors and specialists recommend not increasing the dose of this drug if it is not necessary, since the consequences or side effects that they may have are not known.

Melatonin in pregnancy for the neurological protection of the fetus

As the fetus’ brain develops during pregnancy, it makes it very sensitive to possible damage before and after 37 weeks of pregnancy; Such brain damage can cause the death of the fetus and if it survives it can have consequences for life such as; paralysis, learning, hearing and speech problems.

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If the brain is not well formed, there may be a deficiency in the production of melatonin in the baby’s body, which results in multiple deficiencies in the body’s alert or surveillance system along with failure of antioxidants in the body.

That is why the administration of melatonin in pregnancy can help protect the brain of the fetus . Studies carried out with some animals such as; Mice, sheep and rats have indicated that melatonin can protect the fetus and its brain from any risk of injury, while it is in the gestation period.

This study served as the basis for starting tests on the recommended doses and amounts to be given to pregnant women. The idea is that this hormone is supplied from the beginning of it, as a preventive measure of a premature gestation or 37 weeks.

However, despite the fact that the studies carried out in animals have demonstrated and supported the efficacy in the use of this hormone, there have not yet been carried out studies in humans that can complete this hypothesis.

Doctors recommend that the mother have a good sleep and a long rest to have a good pregnancy, since the body of a pregnant woman is exhausted and in the rest periods are the moments when the glands begin to secrete and be more active.

Melatonin in neurodegenerative diseases

Melatonin has been studied as a possible essential treatment for degenerative and neurological diseases such as: Alzheimer’s, cancer, immunity problems, cardiovascular diseases, Parkinson’s disease, depression and disorders of the circadian rhythm of sleep.

The prolonged release of this hormone has given good results for the treatment of these diseases. However, there are still very few research studies that have not been completed, simply because the evaluation instruments are very basic.

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However, it has been possible to determine that melatonin receptors seem to be important in memory mechanisms, with the possibility of altering them positively, in order to maintain good health and long-term memory.

Melatonin also inhibits cytotoxicity in the brain, which all medications possess and especially all those drugs used to treat these degenerative diseases in the body, said toxicity being responsible and the main cause of death of neurons in the brain.

Another pathology that can be neurologically treated with melatonin is delirium that may be present in the elderly , as previously mentioned. Although many of them have had very positive results, it is believed that it is too hasty to make a judgment about the effectiveness of this hormone for that purpose.

The latest that has been confirmed is the use of melatonin as a preventive method for some serious headaches such as migraines, migraines and headaches.

Controversy over melatonin

One of the issues that has caused the most stir in the use and appearance of melatonin, is the intake by pregnant women, children and babies. Why? Well, this hormone is very important in the development of the fetus, the lack of melatonin in this phase of human growth can have serious consequences, but also abuse.

Cases where the mother has insufficient blood pressure are not very common, since the mother secretes a maternal hormone that goes beyond the placenta , which contains concentrations of melatonin, which nourishes the baby and begins a biological clock that connects both of them. synchronized way.

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We must take into account how important this synchronization is and the care that the mother must have for it, since any sleep disorder can greatly affect both; It has been shown that the minimum deficiency can have a serious impact on the evolution of the pregnancy, and can lead to unwanted abortion.

This is because without this hormone the growth process of the fetus, its gonads, defense systems and its brain is not possible. Studies have even revealed that this vital substance can protect the child’s brain when there is a brain injury.

Ingesting melatonin while pregnant or breastfeeding is not recommended , since, as in infants, undesirable results can be obtained that can be long-lasting and short-lived, development could be irreversibly affected, causing damage that endangers the life of those named above.

Specialists recommend that these types of groups at risk should be under strict surveillance and regular reviews, in case the intake of the hormone is necessary or preferable to other classes of substance that may cause worse damage.

Currently, experts seek to be certain of what amount is completely safe to take in these cases, however, it has not been possible to diagnose one due to the different risks that can vary due to different factors, which makes it an uncertain path to calculate, whose Consequences can be fatal if they are not measured with absolute precision.

In short, this article presents the general but also very important information to take into account when ingesting this hormone , the knowledge about what we are about to introduce into our body is incredibly relevant. It is essential to be clear about why, when, how much dose, and under what conditions, preferably prescribed by a doctor.

Melatonin is a natural, effective hormone that may bring many benefits , but only when knowledgeable people can classify it as such, for now, is it only for primary and short-term sleep disorders.

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Kathie Sand always saw the world of beauty as the terrain on which to build her professional career, a goal that was clear to her when she was only 15 years old. Her great concern to expand knowledge led her to settle in Paris where she studied hand in hand with the best beauty professionals and with the most advanced techniques for skin care.

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