Ask a Nutritionist: How Important Is Magnesium for Sleep?

Hi Jess, I have a few friends who swear by magnesium supplements for better sleep, should I give them a try?

We often focus on diet and exercise for health, but sleep matters just as much. If you’ve ever found yourself wide awake at 2 a.m., scrolling through articles on how to sleep better, you’ve probably come across claims that magnesium can help. 

But is magnesium really effective for better sleep, or is it just another wellness trend? Let’s break down what the science actually says.

What is magnesium?

Magnesium is an essential mineral involved in over 300 biochemical reactions in the body, supporting functions like energy production and brain activity. It's naturally abundant in many foods and available as a dietary supplement, playing an important role overall. 

What are three things that we need magnesium for?

• Regulate energy levels: Involved in ATP (adenosine triphosphate) production,  converting food into energy needed for various cellular processes. 

• Aids muscle and nerve function: Plays a key role in muscle contraction and relaxation, as well as the transmission of nerve signals throughout the body.

• Bone health: Magnesium supports calcium metabolism, crucial for maintaining strong bones and teeth.

Does magnesium help with sleep?

Let’s explore what the science says about magnesium’s role in sleep, including different forms of magnesium and the types of studies conducted.

A 2022 systematic review of 9 studies (both observational and clinical, involving 7,582 adults) found that higher magnesium status was associated with better sleep quality, including less daytime sleepiness, fewer sleep disturbances like snoring, and longer sleep duration, based on observational data. However, the randomised clinical trials included in the review showed an uncertain association between magnesium supplementation and improvements in sleep disorders, with inconsistent findings. 

Looking more closely at individual randomised controlled trials (RCTs), the evidence is mixed:

• A small trial involving older adults with insomnia found that taking 500 mg of magnesium oxide daily for eight weeks led to significant improvements. Participants experienced improvements in both subjective and objective sleep measures, including faster sleep onset, longer total sleep time, and increased sleep efficiency.

• A 2021 meta-review examined three RCTs on oral magnesium supplementation in older adults, with mixed results. On the plus side, people who took magnesium fell asleep about 17 minutes faster on average compared to those who took a placebo. However, the increase in total sleep time was small and did not reach statistical significance. The researchers also noted that the studies had a moderate to high risk of bias and overall low confidence in the findings.

Given these mixed findings, more high-quality, large-scale studies are needed to determine whether magnesium supplementation reliably improves sleep in broader groups.

What foods are naturally high in magnesium?

• Nuts: Cashew, Brazil, Almonds.

• Leafy greens: Spinach, Kale, Swiss chard.

• Seeds: Flaxseed, Chia, or Pumpkin seeds.

• Beans: Black beans, Kidney, and Soya.

• Dark chocolate, with 70% cocoa or higher, can be a great source of magnesium.

Is Magnesium Right for You? Should I take a supplement?

Before reaching for a supplement, it’s always best to focus on a food-first approach. Most people can meet their magnesium needs through a healthy, balanced diet rich in leafy greens, nuts, seeds, and whole grains. While some studies suggest magnesium supplements might improve sleep quality, especially in older adults or those with low magnesium levels, the evidence is still mixed, and benefits aren’t guaranteed for everyone.

If you’re thinking about trying magnesium supplements, it’s a good idea to talk with a healthcare provider first to determine whether you actually need them.

• Dosage:  Up to 350 mg per day is generally considered safe for most adults, but this can vary depending on your health. 

• Form: Magnesium glycinate or citrate are usually better absorbed and gentler on the stomach than magnesium oxide or sulfate, which can sometimes cause digestive upset.

Remember, supplements are just one piece of the puzzle; good sleep habits and lifestyle choices play a big role too.

Words: Jessica Stansfield, RNutr, Huel Nutrition Manager