Research Calls The Safety Of Melatonin Into Question (Especially When Taken Nightly)
Whether your sleep struggles have been due to anxiety, jet lag, or a chronic sleep condition, most of us have had trouble getting high-quality sleep at some point in our lives. This can leave many of us looking for a little help getting our ZZZ's, either in the form of conventional or natural remedies.
Unfortunately, recent research has linked prescription and over-the-counter sleep aids to cognitive decline, and studies have also called the safety of melatonin—a commonly used sleep aid in the United States—into question.
Is melatonin really safe?
If you find it challenging to fall asleep and stay asleep, you're not alone. Melatonin is one of the most ubiquitous supplements in the U.S., with various forms of it available at most grocery stores and pharmacies. In fact, research shows that between 1999 and 2018, melatonin use in the U.S. quadrupled1. (It's more strictly regulated in other countries.)
That said, research shows that we don't really know enough about the safety of supplementing with melatonin, especially using it every night—sometimes for years on end. As the authors of one study2 point out: "Although melatonin is generally regarded as safe, adverse effects have been reported, and data on long-term use and high-dose use are scarce."
Some sleep experts worry that using melatonin regularly may reduce your body's natural productivity of this important sleep hormone.
As Seema Bonney, M.D., the founder and medical director of the Anti-Aging & Longevity Center of Philadelphia, previously told mindbodygreen: "It's important to remember that melatonin is a hormone, and using any hormone regularly can down-regulate your own production of that hormone." Ashley Jordan Ferira, Ph.D., RDN, mbg's vice president of scientific affairs, added, "I have not seen good data to show that high doses of melatonin will not impact your endogenous, natural production of melatonin."
Other risks of melatonin.
Some research has also shown that taking melatonin leads to impaired glucose tolerance, which can harm your blood sugar health in the long term. In one study3 published in the journal Sleep, researchers gave 21 healthy women 5 milligrams of melatonin or a placebo in the morning and evening and then monitored their glucose tolerance for three hours after each dose. They found that those given melatonin had higher blood sugar levels.
There's also significant cross talk between the hormone melatonin and sex hormones like estrogen and testosterone, leading some experts to worry about melatonin's possible long-term side effects on reproductive health.
Alternatives to melatonin.
Unfortunately, we don't know whether taking melatonin long-term is safe. The good news is that there are a lot of nonhormonal alternative sleep aids. If you're concerned about the safety of long-term melatonin use, here are a few alternatives to consider, plus some science-backed lifestyle adjustments for better sleep:
Magnesium is known as nature's "relaxation mineral" because of the role it plays in the nervous system, and it can be helpful for winding down and getting to sleep. Experts recommend a dose of 100 to 200 mg, taken one to two hours before bed. Here are 14 high-quality magnesium supplements to look into.
Cognitive behavioral therapy (CBT)
Set boundaries with work
A 2018 Virginia Tech study showed that the mere expectation of checking work email after hours can cause anxiety and stress that can sabotage your sleep.
Research has shown that mindfulness meditation can significantly improve sleep quality. Here are 10 tips for starting a daily meditation practice that lasts.
Melatonin use has soared in recent years, but there's a lot we don't know about its safety long term. Experts recommend leaning on melatonin as a "once in a while" sleep aid but exploring other nonhormonal options for daily use.
Gretchen Lidicker is an mbg health contributor, content strategist, and the author of CBD Oil Everyday Secrets: A Lifestyle Guide to Hemp-Derived Health and Wellness and Magnesium Everyday Secrets: A Lifestyle Guide to Epsom Salts, Magnesium Oil, and Nature's Relaxation Mineral. She holds a B.S. in biology and earned her master’s degree in physiology with a concentration in complementary and alternative medicine from Georgetown University.