One night of poor, restless sleep is all it takes for friends and family to recommend (even swear by) melatonin. This popular sleep supplement promises to deliver swift, easy, reliable rest, but does research confirm its safety and efficacy?
Sleep affects almost every aspect of health, and it’s increasingly hard to come by. Growing in lockstep with nighttime screen time, melatonin supplements have become increasingly ubiquitous in pharmacy aisles and TikTok stores. But availability is not a proxy for safety, and questions about melatonin dosing, timing, efficacy, and safety abound. While a melatonin supplement can be helpful for some people, it may not be enough to help those with severe insomnia. And experts agree that most people taking it are using too high of a dose.
Here’s what you need to know about melatonin — both the naturally occurring hormone and the supplements on store shelves.
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What is melatonin?
Melatonin is a naturally occurring hormone that helps regulate your sleep-wake cycle and circadian rhythm, or body clock. When melatonin is released, it makes you sleepy; when it is suppressed, you feel alert and awake.
Melatonin is produced in the brain’s pineal gland, a teeny gland that receives and interprets information about light and dark, mainly through the retinas in your eyes. During the day, exposure to light inhibits melatonin production. At night, darkness triggers the synthesis of melatonin, which in turn makes you want to go to sleep. Melatonin levels begin to rise around 9:30 p.m. in adults and naturally continue to increase throughout the night, peaking at about 2 a.m.
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What else does melatonin do?
Aside from your sleep schedule, melatonin regulates other systems affected by your circadian rhythms, such as your body temperature, immune system, and glucose metabolism. Research suggests that melatonin also has powerful antioxidant effects, and supplementing melatonin has been shown to reduce some risk factors related to cardiovascular disease.
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What disrupts natural melatonin production?
Modern life can interfere with melatonin production. Since melatonin is synthesized in darkness, any artificial light at night — from the glow of phone or computer screens to the glare of overhead fixtures — can suppress and delay melatonin, disrupting the natural nudge towards sleepiness.
Studies show that living in areas with brighter environmental lighting pushes sleep at least 30 minutes later and reduces the amount of total sleep. We’re essentially basking in light in our homes at night. Exacerbating the problem is the fact that LED bulbs and fluorescent lights, which emit more blue light waves, are more potent melatonin suppressors than are traditional incandescent light bulbs.
These things may also dim melatonin production:
- Medical conditions such as type 2 diabetes, polycystic ovarian syndrome (PCOS), depression, and Alzheimer’s
- Nutrition habits such as eating meals late at night (especially high glycemic meals), magnesium and/or vitamin B6 deficiency, alcohol, and caffeine consumption
- Certain medications including some hormonal medications, antidepressants, and corticosteroids
- Age. Melatonin levels stay relatively stable until age 40, when they slowly begin to decline. By the age of 60, the day-night difference in melatonin levels is 80% smaller than it is in teens.
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How does a melatonin supplement help?
Melatonin supplements aren’t sleeping pills or sedatives (or any other type of medication).
Melatonin supplements amplify your body’s natural nighttime signals, working with environmental cues such as dim lighting and wind-down activities to enhance your natural nighttime sleepiness.
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How long does it take melatonin to work?
Because of its mechanism of action, melatonin is not immediate-acting. Rather than taking a melatonin supplement at bedtime, time your dose for 30 minutes to two hours before lights out. Your body starts to absorb the supplement within half an hour; it reaches peak levels after 40 to 90 minutes.
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Who may benefit from melatonin supplements?
If you’re lying awake in bed for 30 minutes or more, taking a melatonin supplement may help you fall asleep. Studies show that taking melatonin before bed can reduce the time it takes to fall asleep, but it may not help you stay asleep all night.
“Melatonin works only three or four hours, so [it helps] to induce sleep, but it doesn’t help for sleeping through the night,” says psychiatrist J.J. Sandra Kooij, MD, PhD, head of the Expertise Center Adult ADHD in the Netherlands.
Use of melatonin supplements may benefit people with:
- Delayed sleep-wake phase disorder, who struggle to fall asleep before 2 a.m. and need help shifting their body clocks forward
- Jet lag
- Shift work schedules
- Low melatonin levels after age 50
- Certain neurodevelopmental disorders, including ADHD and autism
Melatonin may help with occasional bouts of insomnia but has limited utility for addressing chronic insomnia or other persistent sleep problems. For these conditions, consult a health care provider who can recommend cognitive behavioral therapy for insomnia (called CBT-I) or prescription medications.
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How much melatonin do you need?
You may need less melatonin than you think.
The goal of taking a melatonin supplement is to augment your body’s natural melatonin release when it is cued by the onset of darkness. It’s considered a physiological dose not a pharmaceutical dose. The average brain makes between 0.1 and 0.9 milligrams (mg) of melatonin each day.
Most research, and experts including Kooij, suggest taking 0.5 mg because it’s more effective and carries fewer side effects than higher doses. This may come as a surprise to anyone accustomed to seeing much higher doses — 3, 5, or even 10 mg — sold in stores. Though it’s sometimes difficult to find a bottle of 1 mg (or less) melatonin, research shows that taking a dose of 0.3 to 0.5 mg is actually more effective and has fewer side effects than taking higher doses.
“The advice is to use really low dosages because if you use higher dosages, the result is not better,” says Kooij. To find 1 mg tablets, you may need to look online, and if you want to stay under 1 mg, you could break that pill in half.
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Are there any risks to taking too much melatonin?
While research on the long-term safety of melatonin is scant, low doses of melatonin are generally well-tolerated. Higher doses (above 1 mg) or extended-release formulations, which are rarely necessary or advised, may cause mild side effects, including:
- Morning grogginess (“hangover effect”)
- Vivid dreams or nightmares
- Headaches
- Dizziness, nausea, or upset stomach
- Low body temperature
One study in adults over 50 found that taking 3 mg of melatonin was more likely to cause side effects, like hypothermia (low body temperature) and a “hangover effect,” feeling groggy the next day, because levels of melatonin remained too high in the morning. Higher doses are also more likely to cause vivid dreams or nightmares.
It’s best to ask your health care provider before you start taking any supplement. They can check for any interactions with medicines you take and address other safety concerns.
Consult your doctor first if you have diabetes or high blood pressure. Melatonin supplements may raise blood sugar and blood pressure levels in people with those conditions.
Don’t take melatonin supplements if you’re pregnant, breastfeeding, or have an autoimmune disorder, seizure disorder, or depression.
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Are over-the-counter melatonin supplements safe?
The FDA does not regulate melatonin, or other dietary supplements, the ways it does prescription drugs. As such, supplement makers don’t have to show that their products are safe and effective.
Studies have found that the amount of melatonin in some supplements may not match what’s on the label. One found that they contained anywhere from 74% to 347% of the labeled quantity.
Look for products approved by the United States Pharmacopeia (USP), an independent nonprofit organization that verifies the dosing of supplements.
