With little FDA oversight, melatonin supplements vary widely in actual dosage, study finds

WASHINGTON — Consumers turning to melatonin gummies to get some help falling asleep might be getting a lot more help than they bargained for, according to a new study published Tuesday in the Journal of the American Medical Association.

Researchers tested the melatonin concentration in more than two dozen gummy dietary supplements that recently launched and that were available at mainstream retailers like Amazon and Walmart. Nearly all of the products had more than 10% more melatonin than advertised. One product was even three times more powerful than the label suggested.

The study underscores the Food and Drug Administration’s lax regulation of melatonin supplements, and natural products more generally. The agency does not review supplements before they hit the market like it does for prescription drugs.


The study is the “perfect example of why the FDA needs to do a better job overseeing dietary supplements,” according to Stephen Ostroff, a former FDA official who served as both acting commissioner and deputy commissioner of the agency’s food program.

Ostroff was reluctant to criticize the FDA for the current situation, and instead argued that the agency needs more money and legal authority to police the growing supplement market.


The new study’s lead author, Pieter Cohen, an associate professor of medicine at Harvard Medical School, was less forgiving. While he acknowledged the FDA’s current legal authority to regulate supplements is weak, he argued the agency shares some of the blame for not enforcing its existing supplement rules.

“We have an inactive FDA,” he said. “The industry knows that if they put whatever they want to in these melatonin products … there’s going to be no consequences.”

In a statement, the FDA promised to “​​review the findings of the paper,” and said it “takes product quality concerns, including under- or over-potent products, seriously.” However, the agency underscored that it “does not have the authority to approve dietary supplements before they are marketed, and firms have the primary responsibility to make sure their products are not adulterated or misbranded before they are distributed.”

Large amounts of the substance have also been shown to have adverse effects in children, prompting an exponential increase in poison control calls in recent years, adding to the researchers’ alarm.

However, one dietary supplement lobbying group argued that variability in strength of the gummies studied is to be expected, and is often purposefully done by manufacturers to ensure they do not degrade overtime and thereby run afoul of the FDA’s rules. Dietary supplements are required to demonstrate they contain 100% of the listed ingredient until their expiration date, and thus manufacturers will “put an overage in to start to be sure that six months from now that when that consumer buys the product, they’re still getting 100% of what’s on the label,” according to Steve Mister, the CEO of the Council for Responsible Nutrition.

The new study is not the first to find quality issues with melatonin supplements. A 2017 study found that the strength of melatonin supplements sold in Canada was also unreliable. That study also found several products containing undeclared amounts of the drug serotonin, which the newly published study did not find.

Mister conceded that he did share concerns about two of the products studied — one which included no melatonin and another that included more than 300% of the advertised amount. He maintained, however, that “there is … absolutely nothing in this study that should alarm consumers.”

However, the report is likely to prompt debate about the potential risks associated with the increasingly popular sleep aid.

A 2022 study found that melatonin use among U.S. adults more than quintupled from 1999 and 2018, and the number of adults taking high doses more than tripled from 2005 to to 2018.

There’s scant information available about the highest melatonin dose consumers can safely take. One of the only recommendations comes from Health Canada, which recommends no more than 10 milligrams per day.

Two of the products studied would provide users more than that daily maximum in just one recommended serving, according to the study.

“This is something that we should be concerned about,” said Jocelyn Cheng, a senior director at the drugmaker Eisai and a spokesperson for the American Academy of Sleep Medicine. “In general [melatonin] is construed as being safe, but in high quantities we just don’t have enough data to say with certainty that it would be safe.”

There’s also increasing evidence that melatonin supplements are landing children in the hospital.

A report published last June found that pediatric melatonin-related calls to poison control centers spiked by 530% from 8,337 in 2012 to 52,563 in 2021, and that 4,097 children were hospitalized as a result.

Cohen argued in an interview that the extra-high potency of the products may help explain the recent spike in poison control calls.

“Having something that [contains] 50% more melatonin could be the difference between whether [a child needs] to go to the emergency room or you just rest it off at home,” he said.

The dietary supplement lobby, however, argued that the new study’s focus on children raises a false alarm, because manufacturers typically warn that their products are not meant for children, and most calls to the poison control center were the result of accidental ingestion.

“It’s a misleading comparison to look at scenarios where kids, for example, got their hands on an entire bottle of adult gummies and became ill after eating multiple servings, versus having slightly more of an ingredient in a single serving that, if taken as directed, would pose no harm,” Mister said.

The JAMA study did not name each product individually, but STAT’s review of the database used to identify the products did reveal that many products included a disclaimer they were not meant for kids. It did appear, however, that certain products bearing that disclaimer also appeared marketed to parents.

One product, for example, included a warning on the back of the bottle indicating it was not meant for people under 18, but the Amazon listing for the product also included a photo advertisement of a mother kissing a young boy good night.

Sarah Ash Combs, an emergency medicine physician at Children’s National Hospital, said the study raises the question of why melatonin and other supplements are sold as gummies in the first place.

“What worries me about things being put into gummy form … is if you get a hold of that and you’re a little kid, you’re going to chow down on it,” Combs said. “It continues to be problematic to me that we put dietary supplements [that are] unregulated by the FDA, such as melatonin … in a form that is attractive to kids.”

Combs added that she was surprised by the variability in strength of products, and it should be a signal to parents considering using melatonin to help their kids sleep that they should try other remedies like limiting screen time and maintaining a bedtime routine before reaching for melatonin. She added that if a parent still thinks their child needs melatonin that they should talk to their doctor first.

Source: STAT