If restless nights have led you to Dr. Google or into the snooze-inducing aisle of the drugstore, you’re probably acquainted with two popular sleep supplements: melatonin and magnesium. They tend to get lumped together as they’re both natural, available OTC, and shrouded by a health halo of risk-free sleep support. But that’s where their similarities end. Each has distinct effects in the body, some of which may—or may not—help you conk out faster or doze more soundly, depending on your particular struggle.
“There aren’t any head-to-head studies weighing melatonin against magnesium,” Dennis Auckley, MD, a professor of medicine at Case Western Reserve University and director of the Center for Sleep Medicine at MetroHealth Medical Center, in Cleveland, tells SELF. And the research on what either can do for sleep, particularly in those with run-of-the-mill insomnia, is far from a slam dunk. Most of the studies are small and short-term, Dr. Auckley says. Still, it’s worth noting a few possible benefits and key differences if you’re curious whether either (or both) could help you.
How do melatonin and magnesium impact sleep?
Melatonin
Melatonin is a hormone that your brain’s pineal gland naturally pumps out each night, when it gets dark, as part of your circadian rhythm (a.k.a. internal clock). It cues your body that it’s time to snooze, hence why melatonin supplements are often used to treat circadian rhythm disorders or resolve sleep struggles that occur with shift work or jet lag, when your body clock is out of sync with the day-night cycle, Dr. Auckley explains.
Outside of these scenarios, taking melatonin may not have as much upside—your brain is already making the melatonin that signals sleepy time each evening, and adding more simply presses the same button. Indeed, studies show taking melatonin helps people fall asleep just about seven minutes faster and increases sleep time by a meager eight minutes.
Other research shows that people taking melatonin do report better sleep quality. But it’s tough to rule out a placebo effect, “which is common with things that you anticipate will help you sleep,” Jennifer Martin, PhD, spokesperson for the American Academy of Sleep Medicine and professor at Herbert Wertheim College of Medicine at Florida International University, tells SELF. That’s not bad per se, except that placebos tend to wear off with time.
Magnesium
Magnesium is an essential mineral that facilitates body processes like muscle and nerve function, energy production, and DNA repair. If you’re not getting enough via foods like leafy greens, grains, nuts, and fish—about 320 milligrams a day for women and 420 for men—you could wind up with a deficiency that raises your risk of poor sleep (and supplementing may help). But as SELF previously reported, your kidneys will latch onto magnesium if you’re running low, minimizing the chances that you feel any symptoms from a deficit.
