Magnesium and melatonin are both popular supplements—especially among people looking to get more shuteye, but can combining them improve your sleep?

It’s possible. Some research shows a joint magnesium-melatonin supplement may improve sleep quality, but more high-quality, large-scale studies are needed to confirm this.

Research on taking magnesium and melatonin together is limited, but some studies suggest it may help certain people sleep better.

One study looking at magnesium and melatonin co-supplementation in women with polycystic ovary syndrome found that taking the two supplements together had “beneficial effects on sleep quality.” In another study, taking a combined magnesium and melatonin supplement for four weeks helped people with sleep disturbances slightly improve their sleep quality.

The mechanisms here aren’t totally clear, but the way magnesium and melatonin interact may indirectly promote sleep.

“Magnesium does have an effect on melatonin levels,” Marie van der Merwe, PhD, coordinator of the applied physiology and nutrition doctoral program at the University of Memphis, told Health. “The amount of magnesium you have can affect how well you synthesize melatonin.”

But you may not need to take the supplements at the same time to reap their benefits, said van der Merwe, who suggested it’s fine to take a magnesium supplement in the morning and melatonin before bed.

The gist: There could be a connection between magnesium levels and sleep, but more research is needed for confirmation.

Magnesium is an essential mineral that helps regulate nerve and muscle function, blood pressure, and blood sugar levels, and is involved in the production of bone, protein, and DNA. It’s also become a popular supplement used to support sleep—but it doesn’t come without risks.

Benefits of Magnesium for Sleep

Some research has found an association between magnesium supplementation and sleep by:

• Improving sleep quality: Getting enough magnesium through diet or supplementation may help improve sleep quality and anxiety in people with a deficiency.
• Relieving muscle tension: Magnesium can help relax muscles and reduce tension, contributing to better sleep.

Risks of Magnesium for Sleep

Using magnesium for sleep hasn’t been well studied. Additionally, supplements aren’t regulated by the FDA for safety and effectiveness, and come with their own set of risks when used. When using magnesium for sleep, it might:

• Take longer to start working: It might take several weeks before you start to see improvements with sleep from magnesium.
• Cause unpleasant side effects: Taking higher doses of magnesium can lead to diarrhea, nausea, and abdominal cramping.
• Interact with other medications: When taken with magnesium, some medications may become less effective, or cause additional side effects. Check in with your doctor about potential interactions before starting a new supplement or medication.

Melatonin is a popular supplement to help with sleep—but it’s actually a hormone your body naturally produces to regulate when you fall sleep and wake up each day. “Melatonin is in charge of running the [internal] clock, and it really is important for regulating your circadian rhythms,” van der Merwe said.

Benefits of Melatonin for Sleep

• Works as-needed: Unlike magnesium, melatonin tends to work as soon as you take it, making it helpful for the occasional sleepless night.
• May help you fall asleep faster: Research shows melatonin helped some people fall asleep about nine minutes faster with a 2-milligram dose compared to placebo.
• Supports sleep timing issues: Melatonin may help shift workers, those with jet lag, or people with sleep timing issues regulate their sleep patterns.

Risks of Melatonin for Sleep

Though melatonin can help some people who are having a hard time getting their sleep schedule on track, it can’t fix all sleep disorders that may be caused by other issues, van der Merwe said. Melatonin supplements also carry their own risks, as they’re not regulated by the FDA.

• Long-term effects of melatonin are unclear: There’s not enough long-term safety data on melatonin for sleep disorders.
• May interact with other medications: Melatonin can interact with certain medications, including antibiotics, antidepressants, and birth control pills.
• Carries risks for certain groups: Melatonin is not recommended for children or those with dementia; it should also be used with caution by people who have seizures or those on blood thinners.

It’s best to speak with a healthcare provider, such as a primary care physician, before trying any new supplements or supplement combinations, including magnesium and melatonin.

Van der Merwe noted that sleep issues may be caused by something supplementation won’t fix. Difficulty sleeping has been linked to cardiovascular disease, type 2 diabetes, depression, and other health conditions.

If you’re still interested in trying one or both supplements, your doctor can help you assess the best time of day to take a magnesium supplement, a melatonin supplement, or one that combines both.

“Melatonin [should] get increased at nighttime,” van der Merwe explained, so you need to take the supplement “at a very specific time during the day. If you take melatonin in the morning, you screw up the whole [internal] clock.”

Though supplements said to support sleep, like magnesium and melatonin, have become popular in recent years, it’s ultimately worth checking with someone before you take them to establish whether they may help you.

“It’s important for people to realize it’s not a sleeping pill,” van der Merwe said. “You’re affecting the intrinsic machinery of your body—you’re slowly tuning it to function optimally—so it really is important for people to reflect on what might be the issue.”