Magnesium or Zinc: Which Supplement May Help You Sleep Better?

If you have trouble drifting off or you wake up feeling unrefreshed, you may be wondering whether a supplement could make a difference. Magnesium and zinc are two commonly used options, since both minerals are involved in the body’s sleep regulation.

So, is one better than the other? The evidence is mixed, and any effect may depend in part on whether you are already low in either mineral. Here is what to know about magnesium and zinc for sleep, along with a few things to consider before trying either one.

Magnesium and Sleep

Magnesium is essential for many functions in the body, including sleep. It may support rest in several ways:

• It helps regulate the production and release of hormones and neurotransmitters tied to stress and sleep, including melatonin and gamma-aminobutyric acid (GABA).

• It may encourage relaxation by calming the nervous system and easing stress and anxiety.

• It can help muscles relax after contraction, which may support physical rest.

Research suggests magnesium may help people sleep longer, fall asleep faster, and improve overall sleep quality, especially in those with low magnesium levels. Still, studies also show it may not provide the same benefit for everyone, particularly when magnesium levels are already normal.

Zinc and Sleep

Zinc also plays a part in sleep regulation. It helps produce and control serotonin and melatonin, two hormones linked to sleep and mood. There is also evidence that zinc influences the brain’s sleep-wake cycle through its effect on GABA.

Some studies have found that people who take zinc supplements, or consume zinc-rich diets, report falling asleep faster, feeling more rested after deep sleep, and seeing overall improvements in sleep quality. People with normal or higher zinc levels are also more likely to report good sleep health and getting 7 to 9 hours of sleep each night.

However, other studies have not found zinc supplements to improve sleep quality. More research is needed to determine the ideal dose and zinc’s exact role in sleep.

Which Supplement May Be Better for Sleep?

Magnesium and zinc support different biological processes that affect sleep. Magnesium is thought to help with physical and mental relaxation. Zinc appears to play a bigger role in deep sleep and the sleep-wake cycle, somewhat similar to melatonin. Although both minerals have been linked to falling asleep more quickly, no studies have directly compared them.

The best choice may depend on the sleep issue you are trying to address. If your main problem is relaxing or falling asleep, magnesium may be the better fit. If you fall asleep easily but still wake up feeling tired, zinc may be more helpful.

Your current mineral levels can also help guide the decision. Normal magnesium levels in adults are about 0.75-0.95 millimoles per liter (mmol/L) of blood, while normal zinc levels are about 80-120 micrograms per deciliter (mcg/dL) of blood. A healthcare provider can check these levels through routine lab work. If either level is low, a supplement or foods rich in magnesium or zinc may be worth considering.

Possible Side Effects of Magnesium and Zinc

Magnesium supplements are generally considered safe when taken at the recommended dose. The most common side effects are gastrointestinal, including nausea, diarrhea, and stomach cramps. The tolerable upper intake level for magnesium supplements in adults is 350 milligrams per day. Very high doses can cause serious problems, such as low blood pressure (hypotension) and abnormal heart rhythms (arrhythmias).

Zinc is also considered safe at recommended doses. Possible side effects include nausea, vomiting, and stomach pain. Very high doses may affect immune function and reduce the amount of iron in the body. The tolerable upper intake level for zinc in adults is 40 milligrams per day, and doses above that may increase the risk of these side effects.

Magnesium and zinc can be taken together safely. Still, both can cause gastrointestinal side effects, so if you use both, pay attention to how your body responds and consider using only one if problems arise.

Other Helpful Sleep Aids

Sleep is important for overall health. For people dealing with insomnia or other sleep concerns, other supplements may also support better rest. Common examples include melatonin, L-theanine, tart cherry, and valerian root.

You can also improve sleep without medication or supplements. Helpful habits include:

• Going to bed and waking up at the same time every day

• Exercising regularly, but not right before bedtime

• Eating a nutritious, balanced diet

• Following a calming bedtime routine every night

• Limiting screens or other electronic devices for at least 30 minutes before bed

• Keeping the bedroom quiet and cool

• Reducing caffeine in the afternoon and evening

• Avoiding large meals and alcohol before bed

If you have questions about improving your sleep, speak with a healthcare provider.