Melatonin is a natural hormone
A good night’s sleep is a crucial part of a healthy lifestyle. If you struggle to get enough shut-eye through the night, you might be tempted to take melatonin for sleep. But did you know that you already have melatonin in your body? According to the National Sleep Foundation, it’s a natural hormone made by the body’s pineal gland, which is the size of a grain of rice and located just above the middle of the brain. During the day the pineal is inactive, meaning levels of the hormone are barely detectable. However, when the sun goes down, the pineal “turns on” and begins to produce melatonin—typically around 9 p.m. As a result, the hormone’s levels in the blood rise sharply and we begin to feel sleepier. For about 12 hours—throughout the night—those blood levels stay elevated, before the light of a new day when they fall back to low daytime levels.
It’s not a cure for insomnia
While the supplement may be taken to help treat sleep problems, it’s not a cure for insomnia; it can help induce sleep, but it won’t help you stay asleep. According to the Mayo Clinic, this supplement is effective for conditions such as jet lag, seasonal affective disorder (SAD), controlling sleep patterns for people who work night shifts, preventing or reducing problems with sleeping and confusion after surgery, and reducing chronic cluster headaches. If you respond well to the supplement, there’s no reason you can’t continue to take it long-term without any negative side effects, but relying on it too heavily could have a negative effect. “It can de-sensitize your receptors so they’re no longer responsive to lower doses of melatonin,” says Andrew Westwood, MD, a board-certified sleep physician and assistant professor at Columbia University. “Then, if you come off [the supplement], you might have difficulty sleeping—and require more and more [of it] to fall asleep.”
What you see is not always what you get
Many people who have difficulty falling asleep take an over-the-counter melatonin supplement, which doesn’t require the FDA stamp of approval. While there’s no cause for panic—in general, melatonin is considered safe—this means very high doses can be sold, sometimes containing unknown additives. “These can have unwanted drug-like effects or unwanted side effects,” says Brunilda Nazario, MD, associate medical director at WebMD. “A dose of 0.3 or 0.5 mgs at night helps induce sleep but higher doses can produce daytime sleepiness, grogginess, reduce physical performance, and cause a decrease in normal body temperature,” she says. Because the supplement isn’t regulated, levels of melatonin can vary. A study published in the February 2017 issue of the Journal of Clinical Sleep Medicine revealed that the melatonin content of dietary supplements often varies widely from what is listed on the label. Sanjeev Kothare, PhD, Director of the Pediatric Sleep Center and Sleep Education at NYU Langone, adds that the risk for allergic reaction can also vary, due to the carrier in the formulation. Here are more things you might be allergic to.