Melatonin use significantly increases across US
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The reported prevalence of melatonin use significantly increased among adults in the United States during a recent 20-year period, survey data show.
During this timeframe, researchers also found an increase in self-reported melatonin use that exceeded the typically recommended daily dosage of 5 mg. Although, overall, the prevalence of higher-dose melatonin use remained “very low,” researchers wrote.
Previous research has suggested that one in 17 children takes melatonin at least once per week.
Melatonin, “one of the key hormones governing circadian rhythm, is indicated for treatment of circadian rhythm sleep disorders and, despite insufficient evidence, is widely used as an over-the-counter sleep aid,” Jingen Li, MD, PhD, of Dongzhimen Hospital and the Beijing University of Chinese Medicine, and colleagues wrote in the new study.
The supplement’s antioxidant and anti-inflammatory properties have spurred studies into its possible therapeutic value for several diseases, they wrote.
“Although melatonin is generally regarded as safe, adverse effects have been reported, and data on long-term use and high-dose use are scarce,” Li and colleagues continued. “The heterogeneity in over-the-counter formulations further supports the need for a broader understanding of consumption of exogenous melatonin in the population.”
The researchers analyzed National Health and Nutrition Examination Survey (NHANES) data regarding dietary supplement use during the past 30 days. They also looked at daily dose consumed from 1999 to 2000 through 2017 to 2018 cycles and noted that NHANES did not track melatonin use that exceeded 5 mg daily until its 2005 to 2006 survey. The analysis included information from 55,021 adults (mean age, 47.5 years; 52% women), of whom 93.9% had verified supplement use.
Li and colleagues reported in JAMA that the overall reported weighted prevalence of melatonin use increased from 0.4% (95% CI, 0.2-1) in 1999 to 2000 to 2.1% (95% CI, 1.5-2.9) in 2017 to 2018, and that the first uptick in melatonin consumption was reported in the 2009 to 2010 survey. Although trends closely and significantly aligned among all sex and age cohorts, some subgroups had a small number of reported melatonin users. The researchers recommended interpreting the subgroup analyses with caution. The reported prevalence of melatonin use greater than 5 mg daily increased from 0.08% (95% CI, 0.02-0.38) in the 2005 to 2006 survey to 0.28% (95% CI, 0.13-0.6) in the 2017 to 2018 survey.
“These estimates may raise safety concerns, especially given that the actual content of melatonin in marketed supplements may be up to 478% higher than the labeled content and that evidence supporting melatonin use for sleep disturbances is weak,” Li and colleagues wrote. “The growing use of exogenous melatonin in the general population and its expanding therapeutic potential provide impetus for the acquisition of robust evidence of long-term safety of melatonin supplementation.”
Perspective
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Mary Ann Kliethermes, BS Pharm, PharmD, FAPhA, FCIOM
Li and colleagues wrote that melatonin intake began increasing the same year that expensive prescription melatonin antagonists became available and could explain why many people began buying over-the-counter forms of melatonin.
Although more studies are needed, the current data suggest melatonin is a relatively safe medicine. A recent meta-analysis showed that melatonin-associated side effects — drowsiness, headache and dizziness — were no different than in those subjects who received placebo. As far as I can tell, there has only been one death that may have been caused by a melatonin overdose, and that was an infant.
To date, melatonin as the active ingredient does not appear to react harmfully with most of the common medications such as BP-lowering and glucose-lowering drugs. However, melatonin may interact with warfarin, a common medication some people take to prevent blood clotting. People taking warfarin may need to be extra careful if they also take melatonin as it may increase their risk for bleeding.
The biggest concern I have about melatonin is that as a dietary supplement it is not fully regulated by the FDA, which means its manufacturers can make a pill with various amounts of melatonin and call it melatonin 5 mg. For instance, one melatonin 5 mg pill could be 80% of that amount of melatonin, another lot could be 60% of that amount of melatonin and another pill could be another percentage. Conversely, if a label of a drug approved by the FDA says the drug contains 5 mg of a specific substance, the amount of that substance in the medication must be within 5% of that amount.
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Daniel J. Buysse, MD
These findings suggest to me two main conclusions. First, poor sleep is an increasingly common concern for many Americans. This could be due to increased prevalence of sleep problems, to increasing awareness of sleep problems or a combination of the two. Second, the findings suggest to me that many adults desire non-prescription and non-medication remedies for their sleep problems.
Melatonin is perceived by many as being a natural remedy. While it is true that melatonin is not a drug, it is also important to remember that it is a hormone — the only hormone I can think of that is available in pill form without a prescription in the United States.
Our pineal gland normally produces melatonin at night. Blood levels produced by melatonin pills or capsules can be 10 to 100 times higher than the normal levels produced by our own bodies. While melatonin appears to be safe and well-tolerated by most people, we do not know all the implications of the high melatonin levels produced by pills or capsules.
Professor of Psychiatry and Clinical and Translational Science, University of Pittsburgh School of Medicine
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