Earlier this year in Indiana, day care director Tonya Rachelle Voris was fired and arrested for feeding melatonin supplements to young children in the New Life Church’s childcare program without parental consent. Voris now faces 11 counts of neglect of dependents and six counts of reckless supervision by a child care provider.
The use of melatonin, a common sleep aid, has increased significantly in the last two decades. More than five times as many adults in the U.S. took melatonin in 2018 than in 2000. Kids are also exposed to or given melatonin: a 2020 study found that 1.3 percent of children and adolescents take the supplement. But although melatonin is an accessible and easy method to help with sleep, it isn’t always the most effective remedy, especially for children.
In the U.S., melatonin is categorized as a dietary supplement and thus doesn’t require a prescription, whereas in the European Union, the U.K., Australia, Japan and Canada, it is available by prescription only. For kids, there’s no universally agreed-upon dosage or age at which they can start taking the supplement. With its availability over the counter in drug stores and supermarkets and inclusion in a variety of flavored gummies, melatonin is easier to use—and misuse—than ever before. Scientific American reached out to experts to discuss the way melatonin works in the body, its proper dosages and its appropriate use for children.
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What is melatonin?
Melatonin is a hormone produced in the brain in response to darkness that signals that it’s time to sleep. This neurochemical comes from the pineal gland, a petite structure located in the center of the brain that philosopher René Descartes once described as the “seat of the soul” and rational thought. The gland produces about 0.3 milligram of melatonin per day and has no other known functions.
This bedtime hormone isn’t a soporific (sleep inducer) but a part of the circadian rhythm, a person’s internal biological clock that’s tuned in to the sleep-wake cycle. Once produced, the hormone enters the bloodstream and fluid surrounding the brain and spinal cord. The body produces 10 times more melatonin at night than during the day, so when melatonin receptors detect this peak, they register that it’s nighttime.
What are melatonin supplements used for?
Consumers in the U.S. primarily use over-the-counter melatonin supplements as a sleep aid. These supplements, including sugary gummies, typically offer much higher doses than what the pineal gland produces to help shift circadian rhythm to night mode. Melatonin dosages will affect people differently, and more research is needed to understand the most effective amounts to assist sleep. Some research does show that supplemental melatonin works best when taken two hours before bedtime, as opposed to right before sleeping.
One serving may be listed as containing as little as 0.1 mg and up to 20 mg of the hormone, though 3, 5 and 10 mg per serving are the most common amounts. Getting that intended dose may be challenging, however: a study recently published in JAMA found that in 25 brands of over-the-counter melatonin gummies, the actual dosage significantly differed from what was advertised. One type of gummy was found to contain almost 3.5 times the labeled quantity of melatonin.
Credit: Amanda Montañez; Source: “Quantity of Melatonin and CBD in Melatonin Gummies Sold in the U.S.,” by Pieter A. Cohen et al., in JAMA, Vol. 329, No. 16; April 25, 2023 (data)
Some studies suggest that melatonin supplements may be the most help to adults suffering from jet lag or a wrecked sleep schedule. They are not the best remedy for someone with insomniaor a night shift worker. "There [are] just some preliminary studies that suggest [melatonin] might be helpful in some certain specific situations, but even in those situations, the data is not definitive," says Pieter Cohen, lead author of the JAMA study and a general internist at the Cambridge Health Alliance in Massachusetts.
Cohen says that the best indicator of whether a labeled dosage is trustworthy is third-party certification from nonprofit organizations that test final batches of a company’s product for quality, such as the U.S. Pharmacopeia and NSF (formerly the National Sanitation Foundation).
Can children take melatonin supplements?
From tots to teens, kids don’t always have the most regular sleep habits. Melatonin gummies may seem like an easy way to regulate bedtime for both stress-addled high schoolers and wired toddlers, but experts say they shouldn’t be a constant strategy to fall back on.
Melatonin is an active hormone that should be taken more seriously than “a glass of warm milk or singing a lullaby to help someone go to sleep,” Cohen says. While our bodies produce the hormone naturally, careful consideration must go into the decision to take it as a supplement, especially for kids.
“There are other, more effective ways of getting kids to sleep,” says Ken Sassower, a pediatric neurologist at Massachusetts General Hospital. And as with other supplements, more doesn’t necessarily mean better. If a low-dose gummy doesn’t do the trick, popping another one probably won’t either.
Melatonin is, however, used to help safely regulate sleep in children with attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD), both of which are associated with circadian rhythm disturbances. “It’s been accepted in the management of autism sleep issues,” Sassower says. While recent studies find that melatonin may be a safe and effective treatment for these conditions, researchers such as Sassower say this use requires more study.
In kids without conditions such as ADHD and ASD, there’s not much evidence-based guidance regarding the best age for use. The particular brand of melatonin gummies that Tonya Rachelle Voris gave at the day care in Indiana was recommended for kids age four and older. The children she gave the supplements to were one to four years old.
According to Phyllis Zee, a sleep neurologist at Northwestern University’s Feinberg School of Medicine, while “there is no data on which age group should or should not take melatonin,” caretakers should make a joint informed decision with a health care professional on a case-by-case basis. She explains that doses below 1 mg appear to be safe for kids.
Is it possible to overdose on melatonin?
The concept of a melatonin “overdose” remains controversial depending on how one defines an overdose. Excessive amounts of the hormone may result in many different side effects, including nausea, vomiting, headaches, mild hypothermia, fatigue, confusion, nightmares and low blood pressure. It’s extremely unlikely that taking high doses of melatonin will cause death. In one case, a 42-year-old woman survived after ingesting 120 mg and receiving emergency treatment, including a stomach pump. But for children, too much melatonin can cause serious, even life-threatening, poisoning. Between 2012 and 2021, two children died out of more than 27,700 who were treated for pediatric melatonin ingestion at health care facilities.
Children will always have a lower threshold for overdose than adults because of their size. And they may be enticed by the fruity gummies, which could increase their risk of ingesting higher amounts of melatonin if they are not carefully monitored. Cohen says that if a child has intentionally or unintentionally eaten more than twice the recommended serving size of melatonin for their age and size, that merits a call to a pediatrician.*
What’s more, many melatonin supplements also contain cannabidiol (CBD), an ingredient that is active in cannabis and usually derived from hemp. Cohen says children should never take CBD. Combination melatonin-CBD supplements may also have much higher levels of the cannabis compound than advertised, as shown in Cohen and his colleagues’ recent JAMA study. In one of the study samples, a combination gummy supplement contained no melatonin, only CBD.
Our bodies may naturally produce melatonin, but taking additional amounts of the hormone should be done with caution. Melatonin supplements have been characterized as one of the “least toxic” medications. Adults and caregivers still should not use them recklessly and should be aware of the side effects.
“As a parent, I can tell you I wouldn’t give melatonin to my kids unless my pediatrician recommended that I do that,” Cohen says.
*Editor's Note (5/5/23): This sentence was edited after posting to better clarify Pieter Cohen’s comment on when a child’s consumption of melatonin warrants medical attention.