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Can You Take Too Much Melatonin?

Jodi Helmer
by Jodi Helmer
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Can You Take Too Much Melatonin?

Whether crisscrossing multiple time zones or tossing and turning several nights in a row have left you desperate for a good night’s sleep, popping a few melatonin pills could help ease your sleep situation.

Melatonin, a hormone produced in the pineal gland, a small gland in the brain, helps regulate the sleep/wake cycle. Your melatonin levels rise in the evening (after the sun sets), sending a signal to the brain that it’s time to go to sleep; conversely, melatonin levels drop in the morning (as the sun rises) to prepare you to wake up.

Insomnia, shift work and jet lag can interfere with your natural production of melatonin, making it harder to regulate your sleep/wake cycle. Several studies have shown taking melatonin supplements, which are available as pills, gummies, lozenges and liquids, can regulate your sleep patterns and help you catch some much-needed zzz’s.

A Cochrane Review called melatonin “remarkably effective” for easing jet lag, especially for air travelers crossing five or more time zones. Studies published in the Journal of Pediatric Psychology and Sleep Medicine Reviews found the supplement helped children and adults with insomnia fall asleep faster and wake up fewer times during the night.

News on the effectiveness of melatonin has reached the masses, helping sales of the supplement skyrocket. According to the U.S. Department of Health and Human Services, more than 3 million American adults have taken melatonin, making it one of the most popular supplements on the market.

While most of the research is positive, it might be possible to have too much of a good thing. Here are four things to consider before taking melatonin supplements:


Do some research before purchasing melatonin supplements. A 2017 study published in the Journal of Clinical Sleep Medicine analyzed the content of 31 different melatonin supplements and found less than 30 percent contained the dosage advertised. Some of the supplements had 83% less of the active ingredient than listed on the label, and some had a whopping 478% more melatonin than the label stated.

W. Christopher Winter, MD, neurologist, sleep researcher and author of “The Sleep Solution,” calls supplement labeling “the Wild West” because it’s unregulated. In fact, the U.S. Food and Drug Administration (FDA) considers melatonin a dietary supplement, which means it’s not subjected to the same strict rules as prescription or over-the-counter medications — and that lack of oversight can contribute to incorrect labeling.

When shopping for melatonin, the American Academy of Sleep Medicine suggests looking for supplements with seals from the United States Pharmacopeial Convention — labeled as USP Verified — which certifies the products meet certain standards.


Melatonin might be marketed as an all-natural, safe sleep aid but that doesn’t mean the supplement is without side effects.

The most common complaints associated with melatonin use include headaches, drowsiness, dizziness and stomach upset. Melatonin is also associated with a few more serious side effects, including depression, anxiety, low blood pressure and mild tremors. Despite some users reporting increased feelings of daytime sleepiness after taking melatonin, research found no effect on attention, concentration or reaction times.

Cristin Gregory, a licensed acupuncturist, notes that, “because it’s a hormone, you want to be cautious about [overusing] it and only take it when needed.”

In adults, short-term use appears safe but less is known about long-term melatonin use, according to The National Institutes of Health. Even less is known about the effects of melatonin on children.


The journal Sleep Medicine published data on melatonin dosage that recommended 0.3 milligrams for maximum effectiveness, but the supplements sold in stores often contain much more of the active ingredient. You can’t overdose on melatonin but taking too much could cause the melatonin receptors in the brain to become unresponsive, rendering the supplement ineffective.

Gregory suggests taking 1–2 milligrams of melatonin one hour before bed, or trying something even lower if you’re new to melatonin.

“Start with a low dose because taking too much could keep you awake,” she explains.

Melatonin should never be mixed with alcohol, and it’s a good idea to talk to your healthcare provider about possible interactions with other medications. Melatonin could interact with certain medications ranging from blood thinners, immunosuppressants and diabetes medications, according to the Mayo Clinic.


Melatonin can be effective for helping you drift into dreamland but it should be combined with good sleep hygiene, including sleeping in a cool, dark environment, establishing regular sleep/wake times and steering clear of screens before bed. (A dark environment can also help boost natural melatonin production, notes Gregory, which can help you rely on your own production of the hormone to induce sleep, instead of taking a supplement).

While it can be helpful to overcome jet lag or adjust to the odd sleep schedule associated with shift work, Winter cautions against over reliance on melatonin, explaining, “Rather than taking it night after night, you need to get a deeper understanding of why you’re struggling to sleep and address those root problems.”

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About ZzzQuil

Everyone deserves a good night’s sleep. Try Vicks ZzzQuil PURE Zzzs, and get the sleep you need — drug-free. PURE Zzzs works naturally with your body to support sleep and is specially formulated with an optimal level of melatonin, shown to help regulate your sleep cycle without next day grogginess*. It also contains a unique botanical blend of lavender, chamomile, lemon balm and valerian root. *THESE STATEMENTS HAVE NOT BEEN EVALUATED BY THE FOOD AND DRUG ADMINISTRATION. THIS PRODUCT IS NOT INTENDED TO DIAGNOSE, TREAT, CURE OR PREVENT ANY DISEASE.

About the Author

Jodi Helmer
Jodi Helmer

Jodi Helmer writes about health and wellness for publications like WebMD, AARP, Shape, Woman’s Day, Arthritis Today and Costco Connection among others. She often comes up with the best story ideas while hiking with her rescue dogs. You can read Jodi’s work or follow her on Twitter @helmerjodi.


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