Melatonin does not cure insomnia and can be harmful in excess – 01/14/2024 – Balance

For many Brazilians, sleeping is not as simple a task as it seems. According to studies by the Oswaldo Cruz Foundation (Fiocruz), sleep-related illnesses, including insomnia, affect an impressive 72% of the population. From meditation to prescription drugs, there are several alternatives sought by those who want to sleep better. One of them is melatonin supplementation. However, some care needs to be taken.

Melatonin is a hormone naturally produced by the human body. It is capable of stimulating sleep and regulating the circadian cycle, a type of biological clock that guides the body’s daily activities. Produced and secreted by the pineal gland in the brain, melatonin prepares the body for sleep when light stimuli decrease.

“It is a rhythm-regulating hormone, which signals to the body that night has arrived”, explains Israel Pompeu, neurologist and collaborator at the Sleep Outpatient Clinic of the HC-FMUSP Institute of Psychiatry (Hospital das Clínicas of the Faculty of Medicine of the University of São Paulo). Paul).

In 2021, Anvisa (National Health Surveillance Agency) approved the use of melatonin for the formulation of dietary supplements, sold without a prescription. Sale has been permitted since 2017, but only with medical advice and in compounding pharmacies.

When is supplementation recommended?

Melatonin supplement is indicated to treat circadian cycle disorders — when the biological clock is misaligned with external times. One example is the sleep phase delay, which causes the sleeping and waking times to occur later than conventional.

“Often, patients are only able to sleep very late and think they have insomnia, when, in reality, they suffer this change”, observes Ícaro Grandesso, otorhinolaryngologist and specialist in sleep medicine.

Another example is REM sleep behavioral disorder, characterized by sudden body movements and vocalizations during the dream phase of sleep. There is also jet lag, a change in bedtime due to a change in time zone.

According to experts, supplementation can also be beneficial for the elderly, who produce the hormone in smaller quantities. However, it is necessary to analyze case by case.

“We also noticed positive responses for children on the autism spectrum. But this is due to the fact that they, in general, fall into circadian rhythm disorders, as their sleep is unregulated”, says neurologist Israel Pompeu.

In addition to helping to reduce latency, the time taken to fall asleep, melatonin can provide more restful rest. This was the reason that led journalism student Reginaldo Ramos, 23, to seek supplementation:

“I started using melatonin when I was 18 years old, because I could only sleep very late, despite going to bed early. When I didn’t take it, I ended up waking up often in the early hours of the morning and feeling tired”, he says.

Although it is effective in regulating the circadian rhythm, melatonin does not treat insomnia. “To date, there is no formal recommendation, even if, in some cases, there is a good response”, points out Israel. “To be considered a treatment for insomnia, melatonin would need to meet a series of criteria, with several studies and clinical states. We don’t have that yet.”

Contraindications

Melatonin is contraindicated for pregnant or breastfeeding women and individuals who drive or operate machinery. People with problems such as cardiovascular and liver diseases should consult a healthcare professional before using it. The same is recommended for those using immunosuppressants and anticoagulants.

“Sometimes, people self-medicate, because they have the feeling that melatonin, as it is produced by the body, is natural and does not generate risks”, notes João Gallinaro, a psychiatrist specializing in sleep medicine.

However, when in excess, the hormone can cause nausea, dizziness, vomiting, drowsiness during the day, nightmares, headache and even worsen depression.

Standard dose and scientific evidence

Anvisa recommends a maximum daily consumption of 0.21 mg. In other countries, the values ​​are higher. In the UK, the official recommendation is that short-term sleep problems should be treated with 2mg daily. For long-term problems, the dose can be as high as 10 mg.

In the United States, the recommended daily dose generally does not exceed 5 mg, as found in a study published in the scientific journal Jama Network.

Furthermore, in 2020, Anvisa published an analysis on the safety and effectiveness of melatonin. The document, which served as the basis for the regulatory discussion, contains a compilation of systematic reviews of studies.

One of the reviews analyzed ten clinical trials with 984 individuals and found that melatonin was effective in preventing and reducing jet lag. Another looked at 17 studies with 284 people, concluding that melatonin increased sleep efficiency by 3.3% and total duration by 13.7 minutes.

A review of 19 studies with more than 1,600 individuals showed that melatonin helps reduce latency, increase total time and improve sleep quality.

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