In recent years, magnesium has become a bedtime must-have, promising to help you stop waking up at 3 a.m. by preparing your body for deep, peaceful sleep. I've been taking magnesium in the evenings for a while, but lately I've been wondering if I should take melatonin instead.
Both are popular sleep supplements, but is magnesium or melatonin better for reducing 3 a.m. wake-ups? "Neither magnesium nor melatonin is a guaranteed solution, but both can be helpful in certain situations," says Dr Shelby Harris, a board-certified clinical psychologist and behavioural sleep medicine specialist.
Here I ask Dr Harris and Vanessa Rissetto, a Registered Dietician on the Vitamin Shoppe’s Wellness Council, if either melatonin or magnesium can help you sleep through the night and stop you from waking up at 3 a.m., and what the pros and cons of each are. Here's what they said...
Key takeaways: Magnesium vs melatonin at a glance
- While neither magnesium nor melatonin are guaranteed to prevent middle-of-the-night wake-ups, both are effective at helping you to sleep better.
- Magnesium can be used to reduce nighttime awakenings if your broken sleep is caused by stress, tension, or a magnesium deficiency.
- Melatonin is more effective to fall asleep faster, rather than helping you to stay asleep.
- Always speak to your doctor before taking melatonin, as it isn't suitable for everybody.
- When taking melatonin, use the lowest effective dose possible, and discuss dosage times with your sleep specialist first.
What is magnesium for sleep?
According to Rissetto, magnesium is an essential mineral involved in hundred of reactions throughout the body. One such function is promoting calmness as it supports normal muscle relaxation and healthy stress response.
"I often tell people to think of magnesium as creating the right conditions for good sleep rather than forcing you to fall asleep," shares Rissetto.
However, the registered dietician also warns that magnesium "isn’t a magic sleep supplement".
"If someone is deficient, correcting that deficiency can absolutely improve sleep quality, reduce muscle cramping, and ease restless feelings at night," she explains. "But if your magnesium status is already adequate, the effects are usually more subtle."
Dr Harris agrees, explaining that, while magnesium isn't a sleep medication, evidence shows it may help people who are deficient or experiencing stress-related insomnia "by promoting relaxation and supporting healthy sleep quality".
"Certain forms, such as magnesium glycinate, tend to be better tolerated and are commonly used for sleep," the board-certified doctor adds.
What is melatonin for sleep?
Rissetto says that one of the biggest misconceptions about melatonin is that it's nothing more than a "nightly vitamin" or a supplement.
"It's actually a hormone your brain naturally produces in response to darkness, " she clarifies.
The dietician explains that the hormone is an integral part of our body's natural sleep schedule, which is know as our circadian rhythm, sending the body and "internal signal that it's time to wind down".
"As evening approaches, melatonin levels rise, helping prepare your body for sleep, and then they decrease again in the morning," she explains.
However, both Rissetto and Dr. Harris point out that melatonin should not be seen as a sleeping pill.
"As a supplement, it works by signalling that it's time to sleep rather than acting as a sedative," Dr. Harris tells me.
Dr. Harris says that it's most effective when being used for people who are experiencing issues with their circadian rhythm, such as travellers with jet lag and shift workers.
"Though the data behind its use specifically for insomnia isn’t very strong," she warns.
Magnesium vs melatonin: Which is better for deep sleep?
Before we compare the effects that magnesium and melatonin have on disrupted sleep, both Rissetto and Dr. Harris stress the importance of identifying the underlying cause of these nighttime awakenings.
"I’d be asking bigger questions," says Rissetto. "Is the person drinking alcohol? Is menopause playing a role? Do they have sleep apnea? Is blood sugar fluctuating? Are they under chronic stress?"
"Neither magnesium nor melatonin is particularly good at preventing middle-of-the-night awakenings if there’s an underlying cause," she adds.
Magnesium: Pros and cons
For Rissetto and Dr. Harris, magnesium seems to be the clear winner when treating nighttime awakenings caused by stress, nighttime anxiety, muscle tension or magnesium deficiency.
"Magnesium may promote relaxation and improve overall sleep quality, particularly in people who are deficient," says Dr. Harris.
"Magnesium may help some people feel more relaxed, especially if low magnesium levels, muscle tension, or stress are contributing to fragmented sleep," Rissetti tells me.
"Still, the evidence for reducing nighttime awakenings is mixed," the dietician adds, referring to research that indicates further investigations are needs to clarify the relationship between magnesium and sleep.
However, magnesium is still the experts' pick when choosing between the two supplements. "For someone who’s stressed, tense, or not meeting their magnesium needs through diet, magnesium may offer more benefit," Rissetto concludes.
Melatonin: Pros and cons
While melatonin has proved to be a popular aid for helping people fall asleep fast, both Rissetto and Dr. Harris agree that it's not the best option if you want to sleep through the night without waking up at 3 a.m.
"Melatonin primarily helps people fall asleep by supporting the body's natural sleep-wake cycle," says Dr. Harris.
"For someone with jet lag or a disrupted sleep schedule, melatonin may be the better fit as it's generally more helpful for helping you fall asleep than it is for helping you stay asleep," says Rissetto.
"I generally think of melatonin as a tool, not a long-term solution. If someone is using it every night for months because they can’t sleep, that’s a sign we should be asking why they’re not sleeping in the first place," she adds.
Is taking melatonin bad for you?
A November 2025 study found that people using melatonin supplements long-term had around a 90% higher chance of heart failure over five years — causing searches for "is melatonin bad for you?" to balloon the same month.
So, is it best to avoid melatonin supplements altogether, even if they do help you to fall asleep?
"In the U.S., it’s sold as a supplement, so dosing isn’t regulated as tightly as prescription medications, and studies have found that some products contain much more — or much less — melatonin than what’s listed on the label," warns Rissetto.
If you want to try a melatonin supplements for sleep, Risetto says to choose a high quality, reputable brand and remember that more isn't always better.
"Many products contain 5, 10, or even 20 milligrams, when research suggests much smaller doses, often around 0.3 to 1 milligram, may be sufficient for many people," she advises.
Dr. Harris agrees with smaller dosing, saying that melatonin is safest when used at the "lowest effective dose".
"Try 1-3mg max an hour before bed," says Dr Harris. "If you need more than 5mg of melatonin to sleep at night, it likely isn’t the appropriate treatment for you as 5-10 mg is quite a moderate to large dose."
"Working with a sleep specialist can be useful here to figure out specific timing," says thethe board-certified doctor.
