what is it, what is it for and how to take it

For doctors, sleep is as important a physiological need as eating or breathing. No wonder, our body is biologically programmed to start turning off when ambient light starts to fade — giving us the cue to relax and rest at night.

This is only possible because there are a series of processes that start when the sun starts to go down. And one of them is the release of melatonin, a hormone produced in the pineal gland, a structure that is right in the center of the brain.

It is this substance that is responsible for warning organs such as the stomach and liver that it is time to slow down and prepare to rest. But not only that. In parallel, other body processes that only happen while we sleep are getting ready to start. This is the case, for example, of brain activity that involves memory.

The problem is that, with the pace of life in the modern world, with many hours in front of the computer, smartphones and artificial lights on when it’s dark outside, our biological clock has been struggling to get into that rhythm — causing it to be difficult to sleep or keep sleep after going to bed.

It is no wonder, then, that the “sleep hormone”, as melatonin is also known, has been sought after by many people who cannot sleep properly. However, it is not suitable for everyone who has difficulty sleeping and can have some unpleasant effects if used incorrectly.

Next, ask your questions about melatonin.

Melatonin: what it is, what it is for and more

What is melatonin?

Melatonin is a neurohormone, that is, a chemical produced by the body that has a specific physiological effect.

In this case, melatonin is produced in the pineal gland, located in the center of the brain.

What is melatonin used for?

Melatonin has the function of regulating our biological clock, telling the body — and guiding the functioning of organs and metabolism itself — when it’s time to sleep and when it’s time to wake up. It’s called the sleep-wake cycle.

Therefore, it begins to be released in our body at the beginning of the night, when natural lighting begins to fall, and its production peaks a few hours after dark.

When day breaks and light appears on the horizon again, melatonin is no longer produced, preparing the body to wake up and continue with daily activities.

Can Melatonin Cure Insomnia?

Not. First of all, it’s worth making it clear: there are no medical guidelines that recommend melatonin for the treatment of insomnia.

And the difficulty sleeping is not necessarily caused by insomnia: currently, there are about 50 diseases cataloged in the International Classification of Sleep Disorders. Insomnia, as well as apnea (or Obstructive Sleep Apnea Syndrome, as it is also called), another common disease, is among them.

Therefore, before self-medicating, it is recommended to seek help from a sleep medicine specialist to get the correct diagnosis and only then seek supplementation, if necessary.

Who can take melatonin?

Melatonin is indicated by doctors for specific conditions in which the individual suffers from not producing or producing the “sleep hormone” in a wrong or insufficient way.

This is the case, for example, in the circadian rhythm disorder, when the release of melatonin occurs outside the normal rhythm and causes the individual’s sleep-wake cycle to be misaligned with the light and dark cycle of the daily routine.

Another specific case of recommendation to supplement melatonin is REM sleep behavior disorder, in which the person physically reacts (screaming, kicking or hitting, for example) to vivid dreams.

There are still some syndromes and even patients with ASD (autistic spectrum disorder) who may also have changes in melatonin production, requiring replacement to achieve a better quality of life.

Who should not take melatonin?

The substance is not recommended for pregnant or nursing women or children — only under medical supervision.

Individuals with a history of autoimmune diseases, liver or kidney problems, seizures, depression, high blood pressure, or diabetes should also speak with their healthcare provider about whether or not they can take the supplement.

How to take melatonin?

As it is sensitive to light, melatonin should be taken close to bedtime, preferably with the lights off.

Where to buy melatonin?

After the release of Anvisa (National Health Surveillance Agency), at the end of 2021, melatonin can be found in tablets or drops in any Brazilian pharmacy and can be purchased without the need for a medical prescription.

Is it dangerous to take melatonin?

Not. The studies done so far have shown no toxic effects in the use of melatonin by humans, even in high doses.

However, and although the marketing is released by Anvisa, experts do not recommend self-medication.

What are the side effects of melatonin?

The most common effects of melatonin use are excessive daytime sleepiness, dizziness, headache, and nausea.

What is the recommended dosage of melatonin for sleep?

In Brazil, Anvisa authorized the sale of melatonin as a food supplement for a maximum daily consumption of 0.21 mg.

However, the recommended dose may vary — more or less — according to the patient’s condition. Therefore, once again, experts are unanimous in stating that it is best to seek medical advice before using the substance.


Alan Luiz Eckeliprofessor at the Department of Neuroscience and Behavioral Sciences at the Faculty of Medicine of Ribeirão Preto, USP (University of São Paulo); Andrea Bacelarpresident of ABS (Brazilian Sleep Association); Claudia changpostdoctoral fellow in endocrinology and metabolism at the FMUSP (School of Medicine, University of São Paulo), member of the SBEM (Brazilian Society of Endocrinology and Metabology); Cristina Sallesresponsible for the Sleep Medicine service at the University Hospital Professor Edgard saints (Hupes-UFBA/Ebserh) and adjunct professor at EBMSP (School Bahiana of Medicine and Public Health).

About Jenni Smith

She's our PC girl, so anything is up to her. She is also responsible for the videos of Play Crazy Game, as well as giving a leg in the news.

Check Also

Readjustment of health plans – Economy

How a health plan works is similar to how car insurance works. At the base …