It's readily available in drugstores and a common addition to sleep supplements. But the science behind what dosage of melatonin to use and how to use it is often poorly understood, and the long-term side effects of melatonin are unclear. Let’s explore this supplement to better understand its use and misuse.
What Is Melatonin?
Melatonin is a naturally occurring hormone that is secreted by the pineal gland, a small gland in the center of the brain, in the evening and at night.
Melatonin typically increases as darkness descends; its purpose is to signal to your brain that nighttime has arrived. The hormone helps keep your body clock, otherwise known as your circadian rhythm, synchronized with the day and night schedule.
Interestingly, nocturnal animals also secrete melatonin at night, but their brains receive melatonin as a signal to stay awake and become active.
Using Melatonin as a Sleep Aid
Melatonin can be a helpful part of treatment for insomnia, but it is important to understand the reason for your difficulty sleeping before you seek out sleep aids.
Melatonin is not a treatment for all causes of insomnia. For example, those whose insomnia arises due to frequent intrusive thoughts and worries would benefit from an alternative treatment such as cognitive behavioral therapy with a sleep specialist.
Similarly, nighttime sleep difficulties experienced by young children almost always have a behavioral cause and therefore need a behavioral solution. For that reason, melatonin isn't recommended for children as a standalone solution to insomnia.
Most of the data that supports the use of melatonin is related to sleep difficulties that arise from circadian rhythm misalignment. This occurs during travel over time zones, during shift work or during adolescence and young adulthood when the body clock becomes dysregulated. In each of these situations, melatonin can help realign the body clock to promote sleep.
Is Melatonin Safe?
Melatonin is considered safe for short-term use. Unlike those who take pharmaceutical sleep drugs, melatonin users are unlikely to develop dependency, habituate or experience a hangover the next day. There are some common side effects, however, including headache, dizziness, and nausea.
The safety of long-term melatonin use is unknown; there is insufficient data about its effects over time. It is a particularly open question whether the dosage makes a difference in terms of long-term safety. A dose of 0.5 milligrams or less is similar to the amount the brain produces naturally, but many adults take far more — as much as 10 milligrams — which could increase any risks associated with long-term use.
What’s in the Bottle?
In the United States, melatonin is considered a supplement and therefore is not subject to direct oversight by the U.S. Food and Drug Administration.
This means it is hard to know for certain about the purity and actual dosage of the melatonin sold over-the-counter in U.S. drug stores. In fact, a 2017 study published in the Journal of Clinical Sleep Medicine showed that 71% of bottles labeled melatonin included dosages that varied from the label’s claim by more than 10%, ranging from −83% to +478% of the dosage cited on the label. In addition to the highly variable dosage of melatonin in many of the pills, 26% of them were also found to contain serotonin, which was not listed among the ingredients.
To be assured of the reliability of the dose and the purity of the ingredients, look for brands that are “USP verified,” which signifies that supplement has been assessed by the USP Dietary Supplement Verification Program and certified to meet the U.S. Pharmacopeia Convention standards. This verification ensures that the product is not only pure and properly dosed but that its manufacturing process meets FDA guidelines.
Optimizing Your Own Melatonin
The best way to use melatonin to promote healthy sleep is to encourage your brain’s natural production of the hormone. The amount of melatonin we secrete decreases with age, so older adults may have more difficulty promoting natural sleep without supplements. But there are also environmental and medication effects that can change melatonin secretion in people of any age.
Blue light, the light from phones and other screens, tends to decrease melatonin more than other colors. Accordingly, the most easily modifiable behavior is reducing blue light exposure at night. To get your best rest, try to avoid screen exposure for at least 30 minutes prior to bedtime to ensure your brain’s melatonin is secreted properly. Medications such as beta-blockers can also decrease melatonin secretion, so you may want to consult your doctor if you experience issues sleeping while on such drugs.
While melatonin is easily accessible, the science behind its use is not as straightforward. Always discuss your sleep issues with your physician prior to self-medicating with melatonin. There may be underlying conditions that need to be diagnosed and more effective treatment options available for your sleep needs.