For anyone who has ever suffered from insomnia, an over-the-counter supplement like melatonin is alluring. But before you stock up, it’s helpful to have a realistic understanding of what this hormone can—and can’t—do.
Your body already makes its own melatonin. Nestled in the center of the brain, the pineal gland communicates with receptors in the retina—the back of the eye—to know when it’s light or dark. When it senses darkness, it releases high levels of melatonin to prepare you for sleep. When it senses light, it shuts melatonin production down.
Around age 40, your body begins to produce less melatonin, which can lead to age-related sleep problems. By age 90, melatonin levels are a mere 20 percent of what they were in your young adult years.
Whatever your age, you can help melatonin do its job by taking a few simple steps:
• Keep the lights low before bed. Even dim light can interfere with a person’s circadian rhythm and melatonin secretion. Just eight lux—less than a table lamp—has an effect.
• Avoid blue light from computers, smartphones, and tablets for two to three hours before bed. If you can’t avoid them, try using a blue-light filter or an app, like F. Lux or Night Shift to adjust your screens to night-time mode. Compact fluorescent lightbulbs and LED lights produce more blue light than incandescent lightbulbs. • Dim red light is the best choice for nightlights.
• Get exposure to daylight during the morning. Sunlight helps your body produce serotonin, which is the precursor to melatonin.
• Melatonin can also be found in various foods, including corn, cucumbers, asparagus, olives, pomegranate, nuts, seeds, barley, and rolled oats. Studies have reported that consumption of kiwis, tart cherry juice, and salmon may improve sleep, too.
Melatonin affects when you fall asleep, not how quickly, so taking a melatonin supplement is far from a cure-all for insomnia. In fact, studies show that it may shave a mere seven or eight minutes off your wait to fall asleep and lengthen sleep time by about the same—hardly a cure for standard insomnia. The American College of Physicians guidelines strongly recommend the use of cognitive behavioral therapy for insomnia (CBT-I) instead.
But sleep disorders that aren’t simple insomnia are different. Because melatonin affects your circadian rhythm, it can help with issues such as delayed sleep phase syndrome, which is when you consistently fall asleep very late and wake up late the next day.
It may help shift workers, who often struggle to work at night when melatonin levels naturally rise and to sleep during the day when they fall. Studies suggest, however, that light therapy is more effective than melatonin supplements.
The strongest case for supplemental melatonin comes from studies on jet lag. Multiple studies show that taking melatonin close to bedtime when you arrive in a different time zone can help reduce lag symptoms.
There is no general consensus regarding dosage. Melatonin supplements often come in doses of 3 to 5 milligrams (mg), but studies suggest that as little as 0.3 to 0.5 mg per day might be more effective than higher doses in many people. Taking too much of the hormone can cause morning grogginess, headaches, reduced focus, and dizziness, so it’s best to start small. (You might have to get a 1 mg tablet and cut it in half to do so.)
Take melatonin about an hour or two before bedtime to give it time to work. Don’t take it in the morning, as it can reset your internal clock in an unintended way.
Short-term use of melatonin supplements appears to be safe, but there isn’t enough data to assess long-term safety. Be careful of mixing it with other drugs. Melatonin can have interactions with other drugs such as blood thinners, anticonvulsants, some blood pressure medications, and diabetes medications. Melatonin may stay active for a longer time in older people, and it can cause dizziness and drowsiness that can increase the risk of falls.
In 2017, researchers tested 31 melatonin supplements and found that the amount of melatonin in the product didn’t match what was listed on the product label in most cases. They found serotonin in more than a quarter of sampled products.