How to Use Melatonin Safely

Melatonin overuse has become a very common phenomenon in the United States.

In a recent interview with the Journal of the American Medical Association (JAMA), Judith Owens, MD, MPH, director of the Center for Pediatric Sleep Disorders at Boston Children’s Hospital, said an increasing number of children are taking melatonin. Some pediatricians recommend melatonin to parents, who give their children melatonin in an attempt to solve their sleep problems. According to Dr. Owens, melatonin is not a panacea for the problem, and many of these children eventually end up in a sleep clinic.

In 2020, 933 American parents participated in an online survey that showed that 38 percent of their children had sleeping difficulties (pdf). Among these children, 44 percent were given melatonin products by their parents.

The use of melatonin has been growing rapidly, not only among children, but also among American adults. There has been a five-fold increase in use over the past two decades, from 0.4 percent in the 1999–2000 period to 2.1 percent in the 2017–2018 period according to data from the National Health and Nutrition Examination Survey (NHANES). Its whirlwind rise is also evidenced by the rapid increase in sales of melatonin products, from an estimated $339 million in 2017 to $825 million in 2020 and $1.26 billion in 2021.

In the United States, melatonin is an over-the-counter health supplement that people can purchase without a prescription. And Americans are taking ever-increasing doses of melatonin.

In the 2005–2006 NHANES, no respondents reported taking a daily melatonin dose of more than 5 milligrams (mg), which is tens to hundreds of times the normal amount secreted by the human body each night; even insomnia patients don’t need to take that much.

However, by 2018, one in eight respondents took more than 5 mg daily. Some of the melatonin supplements available even come in the form of a single 10 mg dose.

Melatonin Naturally Secreted by the Human Body Helps Improve Sleep

Melatonin is a hormone mainly secreted by the pineal gland. When it was first discovered, the substance was named “melatonin” due to its ability to alter the melanin pigment of tadpoles, making them almost transparent.

One of the roles played by melatonin in humans is to encourage sleep. At night, melatonin conveys the message to the brain and body that it’s bedtime. This is accompanied by drowsiness and drops in body temperature, pulse rate, and blood pressure.

Melatonin synthesis and secretion is inhibited by light; therefore, it is also known as the hormone of darkness. Melatonin levels in humans vary as the sun rises and sets. Secretion of melatonin increases after nightfall, reaches a peak between 2 a.m. and 4 a.m., and decreases gradually during the second half of the night.

Nearly 80 percent of melatonin is synthesized at night, with serum concentrations reaching 80 to 120 pg/mL (picograms per milliliter), while only 10–20 pg/mL is produced during daylight hours.

Melatonin secretion is affected not only by changes in light, but also by age. Melatonin levels are high in

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