COVID-19 study sees hope in melatonin | Inquirer News

COVID-19 study sees hope in melatonin

/ 05:44 AM June 19, 2020

The use of melatonin, a supplement usually taken to help people go to sleep, may help in the early recovery of COVID-19 patients with pneumonia and reduce fatalities among them, according to a study by a team of Filipino physicians and American scientists.

The 10 authors of the study, headed by Inquirer Lifestyle health columnist Dr. Rafael Castillo, said “high-dose melatonin (hdM) may have a beneficial role in patients treated for COVID-19 pneumonia, in terms of shorter time to clinical improvement, less need for intubation and mechanical ventilation, shorter hospital stay and possibly lower death rate.”


Their report, “Melatonin as Adjuvant Treatment for COVID-19 Pneumonia Patients Requiring Hospitalization (MAC19 PRO),” was published on June 15 in a special issue dedicated to COVID-19 of Melatonin Research, a US-based online journal.

The journal’s editors acknowledged the paper as the first clinical report in the world on the use of hdM to treat actual COVID-19 patients.


“This preliminary and important clinical data encourage further and large-scale clinical trials,” the editors said.

Improvement noted

The study noted improvement in 10 patients “within four to five days” after they received hdM (between 36 milligrams and 72 mg per day in four divided oral doses), along with other drugs such as hydroxychloroquine, azithromycin and tocilizumab.

The patients were admitted at Manila Doctors Hospital between March 5 and April 4 after health authorities confirmed the local transmission of SARS-CoV-2, the virus that causes the severe respiratory disease.

None of the patients required intubation and the use of respirators or mechanical ventilators after they were given melatonin through the course of their hospital stay.

They were discharged after an average of 8.6 days following the initiation of hdM. This compared with the 13 days of hospital stay by those who did not receive melatonin.

No significant side effects from the hdM were noted except for sleepiness, which was deemed favorable by all the patients, most of whom had anxiety- and symptom-related sleeping problems.

Only to provide perspective and not to compare, the study said that among 34 patients who were not given melatonin, 12 died and seven required hooking to a respirator or mechanical ventilator to assist breathing.


The researchers, citing several studies, said the main cause of death in severe COVID-19 cases was progressive acute injury and acute respiratory distress syndrome.

Both are believed to be triggered by the excessive swelling of various organs of the body due to the activation of the “cytokine storm,” a severe reaction of the immune system where the body releases too many cytokines into the blood too quickly.

Cytokines are important in normal immune responses, but may be life-threatening and lead to multiple organ failures when the body releases them in large amounts all at once.

Word of caution

The melatonin study was funded by the Department of Science and Technology-Philippine Council for Health Research and Development (DOST-PCHRD).

In a statement sent to the Inquirer, Castillo “cautioned that this was only a descriptive and observational study, and no definite conclusions can be derived from it; hence, the need for the expanded randomized, double-blind, placebo-controlled study, which the group hopes to complete and publish by November of this year.”

A more extensive clinical trial is being planned and would again be funded by the DOST-PCHRD to validate the favorable observations based on the paper.

“We are aiming to build on the use of melatonin as a commonly available supplement to support our fight against COVID-19,” DOST-PCHRD executive director Dr. Jaime Montoya said in a statement.

“If the project proves to be successful, we may be able to deescalate COVID-19 cases better, and possibly reduce the mortality rate of the infection,” he added.

Melatonin is a natural hormone produced by the pineal gland of the brain that regulates the body’s sleep-wake cycle.

It is sometimes taken to help individuals cope with jet lag, delayed sleep-wake phase disorder, anxiety before and after surgery and children with some sleep disorders.


Several studies cited by the paper said melatonin had anti-inflammation, antioxidation and immune system-enhancing effects. It is also shown to reduce the proinflammatory substances triggering the cytokine storm.

There is still no vaccine for COVID-19 approved by the World Health Organization, but a number of treatments are being developed and tested in different countries.

Experts have yet to validate and confirm the efficacy of the steroid dexamethasone, which reportedly improved the condition of severe COVID-19 patients.

The DOST is also funding the clinical trials for the antiviral properties of virgin coconut oil based on the paper authored by Dr. Fabian Antonio Dayrit, a professor at the Ateneo de Manila University.

The Philippines is also participating in a number of clinical trials for COVID-19 vaccines.

The other Filipino physicians involved in the study, all affiliated with Manila Doctors Hospital, are Gino Rei Quizon (coprincipal investigator), Dante Morales, Mario Joselito Juco, Arthur Dessi Roman, Donnah de Leon, Felix Eduardo Punzalan and Rafael Bien Guingon.

The American scientists were Dun-Xian Tan and Russel Reiter from the University of Texas, who have a combined track record of more than 70 years in melatonin biocellular research.

Their 14-page report may be accessed at:

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TAGS: coronavirus Philippines, COVID-19 Philippines, Dr. Castillo, health crisis, Melatonin, pandemic, Quarantine, Study
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