Melatonin (hormone): what is it, what is it for and how to take it?


What is melatonin?

Melatonin is a natural hormone produced by the body that helps to regulate sleep. The body has a kind of “biological clock” that regulates the hours of waking up and sleeping. Its functioning depends on melatonin, which acts as a neurotransmitter, or chemical messenger, which “informs” the body when it is time to sleep.

Some people have deficiencies in the production of this hormone and therefore have a hard time falling asleep. Sleepless nights can affect metabolism, increase stress levels and decrease the quality of life of those who suffer from this problem.

Therefore, looking for a solution is something extremely necessary. Ingestion of melatonin as a supplement is an option for these people, but it should be taken only under medical guidance . The use of this uncontrolled substance may not only have no effect, as worsen the frame insomnia and let the patient tired throughout the day.

In Brazil, the National Health Surveillance Agency (Anvisa) has not yet recognized melatonin as a safe substance. However, its commercialization is legalized in some handling pharmacies.

Despite being relatively safe, to obtain the substance in the national territory, a prescription is still required. Only then is it possible to import melatonin safely. When the patient decides to use the imported substance, he will pay around 120 reais.

However, it is worth remembering that melatonin can have some uncomfortable side effects, such as excessive sleepiness, fatigue , weight gain and even cardiac arrhythmia and worsening depression , for depressed patients.

The first time a record of melatonin was made was in 1958 by American dermatologist Aaron Lerner. In the 1960s and 1970s, the commercialization of the substance began and saw a huge increase in consumption in the 1990s.

As sleep quality improves, many people believe that melatonin has an anti-aging effect, which has not been fully scientifically proven, but which explains the popularity of the substance in the 1990s.

Although not yet completely known, melatonin can be a good option for people who suffer from sleep disorders. Find out more about the substance in the text below!

What is it for?

Melatonin is a hormone naturally produced by the body and responsible for regulating sleep. It is usually indicated for night workers, who need to sleep at alternative times, or for those who have an unusual routine. Check out the main indications:


People who suffer from insomnia may not be producing enough melatonin. Therefore, this medication can be an indication to help these people sleep better.

Diseases that lower melatonin levels

Melatonin can still be indicated for patients with diseases that decrease the levels of production of this hormone, such as Alzheimer’s, Parkinson’s, autism and Attention Deficit Hyperactivity Disorder ( ADHD ).

People working alternative hours

Those who work at night and sleep during the day usually have trouble sleeping, as melatonin is a substance whose natural production is stimulated by the amount of light in the environment.

The more light, the less melatonin is produced and the less sleep the person feels. Hence the possible need for supplementation.

jet lag

It can also be used by people who suffer from the inconvenience of jet lag , a condition in which the person is left with unregulated sleep due to abrupt changes in the time zone.

It is worth mentioning that a simple difficulty to fall asleep is not enough for melatonin to be an indication for you. The best thing to do is to seek the recommendation of an endocrinologist or sleep doctors who can prove any deficiency in the production of this hormone.

If the person using melatonin does not have any deficiency in the production of this hormone, the consequences can be serious. In addition to possible sleep dysregulation, the patient may develop serious metabolic and immunological disorders .

How does it act in the organism?

Our body has a “natural clock” that regulates the time to sleep and the time to wake up. The substance responsible for making this “clock” work is melatonin.

Produced in the pineal gland, melatonin acts as a neurotransmitter, or chemical messenger, whose function is to activate certain brain functions.

Normally, melatonin levels in the body begin to rise as night falls and tend to decrease as soon as dawn.

This is because light is an essential factor for the production of melatonin to occur naturally. So, when it is winter and the days last less, the body can become somewhat confused and increase melatonin levels later or earlier than usual.

The natural production of melatonin decreases with age. Older adults may produce smaller amounts of this substance or may not even be able to produce them sufficiently. It is in these cases that supplementation is indicated.

People who work different shifts, who sleep during the day and work at night, may also receive an indication to take melatonin to regulate the levels of this hormone in the body, after all, these people sleep when there is more light and when the body does not produce this substance naturally.

The big difference between melatonin and other sleeping pills is that it is produced naturally by the body.

Other sleep stimulants can bring a series of problems, such as the development of tolerance to the drug, which makes them less and less efficient, and it is necessary to increase the dosage.

Therefore, melatonin is an alternative. But we must remember, however, that the best thing to do is to take this substance according to medical advice.

Other possible indications of melatonin

It is not yet completely known about all the possible actions of melatonin in the body . Therefore, in recent years, many hypotheses have been raised. Check out some of them below:

Improves migraine

Some studies have indicated that melatonin can help treat migraine in patients who do not respond well to common treatments, which are done essentially with pain relievers and other therapies.

An interesting curiosity is that some of these studies have been done right here, in Brazil. However, it is not yet known exactly what effects it can have. Therefore, a protocol for its use has not yet been adopted and further studies are needed.

Enhances the effects of chemotherapy

Recently, some studies have been done with mice that have shown that melatonin can have a positive effect and enhance the effectiveness of chemotherapy in the treatment of cancer .

No tests have yet been performed on humans , so it is not known whether it will have the same effect.

Helps in cancer prevention

Sleep is a very important factor in regulating the mechanism for controlling new cells. In other words, it helps the body to verify that the new cells are functioning properly.

Therefore, many researchers believe that melatonin can help prevent cancer and the appearance of tumors. Tests on humans are still being carried out and it will be some years before we have a concrete conclusion on the subject.

Treatment of polycystic ovary syndrome

Melatonin is a very important hormone for the body, because, as we have already seen, it influences the action of several hormones in the body, including some that are related to polycystic ovary syndrome.

For this reason, it is believed that melatonin and its supplementation can benefit the treatment of this disease.

However, current research is not focused on trying to see the effectiveness of this treatment, but on verifying the interaction of melatonin with these other hormones. It will still be a few years before we know if it can play a positive role in the treatment of polycystic ovary syndrome.

Improves colic symptoms in babies

Recent research has shown the importance of melatonin and serotonin in the regulation of the intestine. According to experts, serotonin plays a fundamental role in the contraction of the intestinal walls, while melatonin helps in the relaxation of this organ.

The idea that melatonin can help with colic lies in the fact that babies do not have a well-developed pineal gland, causing melatonin production to be deficient.

Therefore, the hypothesis that a supplementation of this hormone in newborns can help with colic is being studied. Unfortunately, we still have no conclusions on the matter.

Treatment for baldness

Baldness, also called androgenetic alopecia, happens, essentially, for two reasons: the decrease of germ cells in the hair bulb and the oxidative stress that acts on the hair .

Recent research has shown that the topical use of melatonin can help fight baldness.

A study done in 2012 in Italy and published in the International Journal of Trichology , studied the effects of topical use of melatonin once a day for 6 months in 35 volunteers between 18 and 40 years old who suffered from the symptoms of baldness.

The results demonstrated a positive effect of the substance. After that period, there was an increase of up to 40% in the capillary count and capillary density of the volunteers.

Today, products manipulated with the substance are already available for sale in Brazil.

Avoid cardiovascular injuries in patients with sores

Research by USP in Ribeirão Preto has been investigating the possible benefits of melatonin in therapeutic doses to help prevent cardiovascular injuries in patients with Chagas disease.

One of the most severe consequences of chagas disease is the appearance of lesions in the heart. However, melatonin induces an anti-inflammatory immune response that can help protect the heart from damage caused by the disease.

So far, the study has been done with animals and clinical trials with humans should be done soon. In an interview with BBC Brasil, Professor José Clóvis Prado Júnior, from the Department of Clinical Toxicological and Bromatological Analysis, said that “If these studies show benefits for Chagas patients, I believe that Anvisa will release them”.

How to take?

The way to use melatonin will vary according to your doctor’s advice. However, we can say that what is usually necessary is to take 1 capsule of the substance about 30 minutes before the time you usually sleep.

Remembering that melatonin does not induce sleep , but only improves its quality.

Doses will vary from 1mg to 5mg according to the indication for each patient. Generally, treatment is started with low doses and it gradually increases, as needed.

Elderly people are those who may need higher doses of melatonin, as the substance stops being produced with age. In such cases, it is possible to find capsules with doses of up to 20mg.

This supplement, however, should only be used under medical advice .

Side effects


Although melatonin has its therapeutic efficiency scientifically proven, it is still a hormone that has many effects on the endocrine and central nervous systems, being able to trigger side effects and interact with other drugs and substances (see more in the topic “ Drug and food interaction ”) .

Since its long-term effects have not yet been fully discovered, it should be taken with caution. Therefore, its supplementation is only indicated when there is a hormonal deficiency of this substance in the body.

If the sleep problem is caused by depression or anxiety , melatonin is contraindicated.

Some of the possible side effects of melatonin include:

  • Irritability;
  • Nervousness;
  • Agitation;
  • Insomnia;
  • Abnormal dreams;
  • Anxiety;
  • Migraine;
  • Lethargy (lack of energy);
  • Psychomotor hyperactivity (agitation with increased activity);
  • Dizziness;
  • Somnolence;
  • Hypertension;
  • Abdominal pain (belly pain);
  • Dyspepsia (heartburn);
  • Dry mouth;
  • Ulceration in the mouth;
  • Hyperbilirubinemia (increased blood levels of bilirubin, a breakdown of red blood cells that can cause yellowing of the skin and eyes);
  • Night sweats;
  • Itch;
  • Rash;
  • Dry skin;
  • Pains in the arms and legs;
  • Menopause symptoms;
  • Astenia (weakness);
  • Chest pain;
  • Glycosuria (sugar in the urine);
  • Proteinuria (proteins in the urine);
  • Changes in liver functions;
  • Weight gain;
  • Excessive drowsiness;
  • Fatigue;
  • Low visual acuity;
  • Cardiac arrhythmia;
  • Lack of concentration;
  • Worsening depression (for depressed patients);
  • Inhibition of calcium absorption, favoring osteoporosis;
  • Increased amount of estrogen in women;
  • Headache;
  • Diarrhea.

Some of these effects are less common than others, being found in approximately 1 patient in 100. The intensity of these effects will depend on the amount of melatonin being ingested; the higher the dose, the greater the risk of any of these effects manifesting.


Melatonin is contraindicated for pregnant women, breastfeeding, people with insomnia caused by depression or anxiety and for children under 12 years of age.

Drug and food interactions

Melatonin can interact with the following medications:


Anticoagulants can act by delaying clotting. The use of these drugs with melatonin can increase the possibility of bruising and bleeding.

Some drugs that decrease clotting include:

  • Aspirin ;
  • Clopidogrel ( Plavix );
  • Diclofenac ( Voltaren , Cataflam etc.);
  • Ibuprofen ( Advil , Motrin etc.);
  • Naproxen (Anaprox, Naprosyn etc.);
  • Dalteparin ( Fragmin );
  • Enoxaparin (Lovenox);
  • Heparin ;
  • Warfarin ( Coumadin ).


Melatonin can inhibit the effects of anticonvulsants in neurologically impaired children.

Antihypertensive drugs

The risk of blood pressure rising to worrying levels is greater when the use of antihypertensive drugs is combined with the consumption of melatonin.

An antihypertensive agent that may have a drug interaction with melatonin is nifedipine  and verapamil ( Calan , Covera, Isoptin, Veralan).

Central Nervous System (CNS) depressants

Melatonin, by itself, can cause drowsiness and numbness. When used in combination with sedatives, it can enhance the sedative effect.

Check out a list of some CNS depressant drugs that should be avoided when using melatonin:

  • Clonazepam ;
  • Diazepam ;
  • Lorazepam ;
  • Phenobarbital ;
  • Zolpidem .

Diabetes Medicines

Diabetes medications are usually used to lower blood sugar levels. What happens is that the consumption of melatonin can increase these levels, decreasing the effectiveness of medicines for diabetes.

If you have diabetes, watch out for signs and monitor your sugar levels closely, as the dose of your diabetes medicine can be changed.

Some of the drugs used for diabetes and which may have drug interactions with melatonin are:

  • Glimepiride ( Amaryl );
  • Glibenclamide ( Diabeta );
  • Insulin ;
  • Pioglitazone (Actos);
  • Rosiglitazone (Avandia);
  • Chlorpropamide ( Diabinese );
  • Glipizide (Glucotrol);
  • Tolbutamide (Orinase).

Birth control pills

The body already produces melatonin naturally. When supplementation of this product is taken, there may be an excessive concentration of this substance in the body.

Some pills that have a drug interaction with melatonin include:

  • Ethinylestradiol and levonorgestrel (Triphasil);
  • Ethinylestradiol and norethindrone (Ortho Novum 1/35, Ortho Novum 7/7/7).


Taking caffeine with melatonin supplements can lessen the effect of the substance, as caffeine reduces the levels of melatonin in the blood.


The fluvoxamine  ( Luvox ) can increase the body melatonin absorption, increasing its effects on the organism.


Concomitant use of melatonin with immunosuppressants may decrease the effectiveness of this medication, as melatonin can improve the immune system.

Some of the immunosuppressive drugs that can interact with melatonin include:

  • Azathioprine ( Imuran );
  • Basiliximab ( Simulect );
  • Cyclosporine ( Neoral );
  • Daclizumab (Zenapax);
  • Muromonab-CD3 (OKT3, Orthoclone OKT3);
  • Mycophenolate ( CellCept );
  • Tacrolimus ( Prograf );
  • Sirolimus ( Rapamune );
  • Prednisone (Deltasone, Orasone);
  • Glucocorticoids .

Price and where to buy

Melatonin is not marketed in Brazil as in other countries, such as the United States, where it can be found on any shelf, as it was not recognized by Anvisa as a safe supplement.

However, in 2017, the regulatory body authorized Active Pharmaceuticals to import and market the substance in compounding pharmacies. In practice, the decision facilitated access to the hormone for therapeutic purposes.

Prices will vary widely from pharmacy to pharmacy, so it is not possible to say with confidence what the price of melatonin is.

Even so, if the patient decides to import the product on his own, a package with 180 capsules of 1mg will cost around R $ 120.00.

Complementary treatments


There are other methods to improve sleep. Understand:


Meditation is a proven method for lowering stress levels and improving life as a whole. The technique consists of focusing on some aspect to leave the mind clear of any thoughts. It is an oriental technique that has been shown to be very effective in improving the quality of life.

An analogy that can help you understand why meditation is a precious technique is the following: imagine a glass full of water and sand. When stirred, both water and sand mix and the water becomes cloudy, making it difficult to see the water translucently inside the glass.

The meditation technique is similar to leaving the glass still, so that the sand begins to descend and settles on the bottom of the glass, leaving the water free to become crystal clear.

Through this technique, the focus improves, as well as patience, and the levels of stress and anxiety decrease. That way, you can “look inside” more easily, since the water is crystal clear.

According to its followers, meditation helps the individual to have a better understanding of himself and to solve personal problems.


Acupuncture is an ancient technique from the east that consists of inserting special needles in specific places on the body. It serves to treat various problems, such as body aches, addictions and stress.


Although some foods are not direct sources of melatonin, they can help to stimulate the production of this substance. Check now the foods rich in the substance and others that help stimulate their production:


Adding a little honey to milk or tea a few hours before bedtime can help you sleep better, as this small amount of glucose reduces levels of orexin, a neurotransmitter that increases alertness levels.

Whole grains

A piece of bread or wholemeal toast is another good option to improve sleep. Whole grains encourage the production of insulin, which helps the neural pathways to produce tryptophan, an amino acid that works as a sedative for the brain.


Vitamins of the B complex has been indicated as a good option to improve the symptoms of insomnia, as they help to relieve stress and reduce anxiety.

A natural source of B vitamins is beans . It contains a handful of different B vitamins, such as B6, niacin and folic acid . However, it is not good to eat beans right before bed, as it takes a long time to be processed and this can impair the quality of sleep.


Yogurt contains large amounts of calcium, which is necessary for the processing of essential sleep hormones, such as melatonin and tryptophan.

Green leaves

Its operation is similar to that of yogurt. The large amounts of calcium will help the body to process sleep hormones.


The egg is a great source of tryptophan, one of the allies for peaceful nights of sleep. Whether you serve it with a cup of tea or whole grain bread, its effects will be enhanced.


All birds contain a large amount of tryptophan. Before going to bed, if you are hungry, including a piece of sliced ​​chicken or turkey in a whole sandwich can be an ally to a good night’s sleep.


Studies have shown that the grape is a fruit with high amounts of melatonin. Although the studies have analyzed only the fruit itself, some researchers believe that the substance can also be found in wine. However, be careful: alcohol can disrupt long-term sleep.


The onion, in addition to being a vegetable rich in nutrients that contribute to health, also helps to improve the production of melatonin.

It has vitamins, minerals and amino acids, the absorption of which facilitates the regulation of the circadian rhythm (the biological cycle of sleep). Regular consumption promotes the elimination of toxins from the body and also relieves excess swelling and fluid retention.


Eating a banana before going to bed is already a well-known good remedy for treating insomnia. That’s because the fruit provides melatonin, in addition to being a source of tryptophan and other essential vitamins and minerals, which help prevent muscle cramps.


Cherries are one of the most recommended foods to improve sleep quality. They provide vitamin A, C and E, whose antioxidant effects decrease the negative action of oxidative stress.


Both nuts and other oilseed varieties contain essential fatty acids, such as omega 3, a type of fat that fights inflammation and other problems associated with cardiovascular health.

They have a modest dose of melatonin and amino acids, which help to improve the quality of sleep.

However, it is worth remembering that the calorie intake that these foods promote is significant, and should therefore not be consumed in an exaggerated manner.


Ginger root , in addition to a spice with anti-inflammatory and antioxidant properties, is ideal for minimizing the effects of free radicals and improving sleep quality.

Its natural oils protect cells against toxins and harmful agents from the environment. In addition, it promotes the increase of melatonin, which will help to improve the night’s sleep.


Considered the most complete cereal, oats provide a large amount of tryptophan, an amino acid that helps to stimulate the production of melatonin.

In addition, among its benefits, it is worth mentioning:

  • Helps to improve digestion;
  • Protects cardiovascular health;
  • Controls anxiety;
  • Improves the functions of the Central Nervous System (CNS);
  • Helps maintain a healthy weight.


Pineapple is one of the fruits that best helps to improve the sleep cycle, promoting a restorative night.

It is also indicated for anyone who wants to have a better functioning of the intestine, since it promotes the balance of the levels of serotonin and melatonin, substances involved in the relaxation of the body to sleep well.

Chamomile tea

Chamomile is known to have a calming effect. Therefore, she is a great ally at bedtime. Drinking a cup of tea without caffeine before bed can be the perfect routine to fall asleep more easily.

Common questions

Does melatonin induce sleep?

No!  Melatonin only helps to improve the quality of sleep. It is a natural hormone produced by the body that, when lacking, can be supplemented.

Is melatonin addictive?

No . Melatonin has no addictive potential and does not create dependency, since it is a hormone naturally produced by the body.

Will melatonin make me feel more tired in the morning?

It depends . If the dosage of melatonin being ingested is correct for your body, it should not make you feel tired . On the contrary, it improves sleep. However, if the doses are higher than indicated, this effect may appear.

Can children take melatonin?

Children, in general, should not take melatonin , as childhood is the stage of life when the body produces melatonin most easily. The only time a child can take melatonin is if the pediatrician or endocrinologist indicates that this is a correct option.

It is worth remembering that the doctor will only indicate the use of melatonin if the child has any problem in the production of this substance, which is very rare in this age group.

The only exception to this rule, however, may be children who suffer from autism and have difficulty sleeping. Understand:

Children with autism

Research published in the scientific journal Journal of American Academy of Child & Adolescent Psychiatry  in November 2017 raises the hypothesis that children who suffer from autism and who have difficulty sleeping may benefit from the melatonin supplement.

In the test, 125 children were divided into two groups: one who received a placebo and another who received a drug that releases melatonin slowly during the night.

Of the 56 children who received the drug, 38 benefited from its use and had more peaceful nights of sleep. In the placebo group, of the 61 children, only 12 showed improvement.

Does melatonin lose weight?

It is true that a healthy and regulated sleep helps you lose weight and maintain an ideal weight. However, it is not possible to state with a reasonable degree of confidence that melatonin or melatonin supplementation helps to lose weight .

This hypothesis arises in people’s minds mainly because quality sleep helps in the regulation of hormones that control satiety (ghrelin and leptin). When one sleeps little or badly, the performance of these hormones is compromised, making the person have to eat more until they are satisfied.

So it is true that good sleep helps to control weight and it may be that melatonin is an ally in this process. However, physical exercise and a balanced diet are still the best and most efficient ways to lose weight.