Magnesium Vs. Zinc: Sleep Experts Share Which Works Best for Sleep

As an essential mineral, magnesium contributes to many different processes in the body, some of which impact your sleep. “Magnesium plays a role in calming the nervous system, which relaxes both the brain and body, helping to fall and stay asleep,” explains Jordan Hill, R.D., C.S.S.D., a registered dietitian at Live It Up. More specifically, it may act on certain brain chemicals that influence relaxation. “Magnesium is thought to work potentially on regulation of neurotransmitters within the brain, specifically the ones that are called “inhibitory” neurotransmitters (like GABA) which promote sleep and can make someone feel more relaxed,” says Kenneth Lee, M.D., the medical director of the Sleep Disorders Center at UChicago Medicine.

In a 2025 study published in the journal Nature and Science of Sleep, people with poor sleep quality who took magnesium glycinate reported modest improvements in their insomnia symptoms, though all results were subjective and those who had the lowest dietary magnesium intake to start seemed to benefit the most. Dr. Lee’s clinical experience aligns with the results; he notes that some of his patients find magnesium helpful while others don’t see any differences from supplementing with the mineral.

The possible side effects of supplementing with magnesium can vary greatly based on the type of magnesium you are taking. According to the National Institutes of Health (NIH), the most common side effects are diarrhea, nausea, and abdominal cramping, which are most frequently associated with magnesium carbonate, chloride, gluconate, and oxide (magnesium glycinate, on the other hand, is one of the most well-tolerated forms). Magnesium can also interact with several medications, including osteoporosis drugs, antibiotics, diuretics, and proton pump inhibitors, per the NIH, so you should check with your physician before starting a magnesium supplement if you take other meds.

“Zinc is a trace element that has some component of assisting with sleep regulation,” says Dr. Lee. “It is a co-factor in the production of other hormones like melatonin and serotonin, meaning it’s a component necessary to ultimately lead to the production of melatonin which is essential for sleep regulation.” According to a 2024 review published in Health Science Reports, supplementing with zinc may lead to improvements in sleep quality but does not have a significant effect for people with sleep disorders, such as insomnia or sleep deprivation.

“There are some small studies that suggest that zinc-rich food may be helpful with sleep onset and some mild improvement of total sleep time,” adds Dr. Lee. “However, whether or not it was clearly the zinc in those food groups that was responsible is unclear.” This is likely because zinc is more of a supporting player in the processes that influence sleep, while magnesium’s impact is a bit more direct. “Zinc mainly helps with general sleep health,” Hill says.

“Zinc as a supplement has not been rigorously tested and therefore the utility and the safety of long-term usage is still questionable,” says Dr. Lee. Per the NIH, high zinc intake may cause nausea, dizziness, headaches, vomiting, or loss of appetite. There are also risks associated with taking high doses of zinc (or exceeding the tolerable upper limit of 40 milligrams per day), namely reduced copper absorption. If used for weeks, the NIH says that this may inhibit immune function or lower levels of HDL “good” cholesterol.

Both magnesium and zinc are important players in the processes that influence sleep, though they play different roles. Therefore, supplementing with each may have different outcomes. “Magnesium mainly helps people who struggle to fall asleep or sleep too little and appears to be better for improving how deep and restorative sleep feels, while zinc supports overall sleep health and lowers the risk of sleep problems,” says Hill. If you are having difficulty settling down at night and achieving the relaxation needed to fall asleep, magnesium may be better to try first. But if you just find yourself feeling more tired during the day and worry your sleep quality is starting to falter, zinc may be a good place to start. Either way, you should always check with a healthcare professional before starting a new supplement.

What’s more, if you’re thinking about taking a supplement to improve your sleep, it’s likely worth trying a few other strategies first. “Sleeping in and of itself is a completely natural process. When we have trouble sleeping, it’s often because our brain and body are stressed and have forgotten how to sleep naturally,” Dr. Lee says. “Therefore, while the supplements can be helpful short term-wise, the care is often centered more on re-teaching the brain and body how to sleep.” Simple changes like setting aside time to relax in the hour before sleep, avoiding exercise and eating in the one to two hours before bed, and only using your bed for sleep and intimacy can be powerful tools for transforming your sleep for the better.

Dietary supplements are products intended to supplement the diet. They are not medicines and are not intended to treat, diagnose, mitigate, prevent, or cure diseases. Be cautious about taking dietary supplements if you are pregnant or nursing. Also, be careful about giving supplements to a child, unless recommended by their healthcare provider.