What is magnesium and why is it important?

Magnesium is an essential mineral found in every tissue of the human body and plays a critical role in maintaining overall health. Involved in hundreds of biochemical processes, it supports everything from energy production and the nervous system to muscle function and cardiovascular health.

Despite its importance, magnesium is often overlooked in discussions around nutrition and wellbeing, even though it underpins many of the processes required for everyday function and long-term health.

In this article, we explore the lesser-known effects of magnesium status on health and performance, as well as the potential benefits of magnesium supplementation.

The role of magnesium in the body

Magnesium is involved in more than 300 enzyme reactions and over 600 cellular processes. These include DNA replication, nervous system activity, energy metabolism, cardiovascular function, and the secretion of parathyroid hormone, which controls bone calcium levels.

In addition, magnesium contributes to protein synthesis, electrolyte balance, cognitive function, memory and mood, and plays a role in reducing tiredness and fatigue.

Magnesium intake and deficiency

Although magnesium is found in a wide range of foods—including leafy green vegetables such as spinach, nuts, whole grains, and egg yolks—many individuals following a typical Western diet consume insufficient amounts. This is largely due to changes in food production and dietary patterns over recent decades, particularly the increased reliance on highly processed foods.

Low magnesium intake has been associated with a range of symptoms, from fatigue, weakness, and muscle cramps or tremors to mood disturbances and abnormal heart rhythms.

Magnesium and Vitamin D: A critical nutrient interaction

Vitamin D has been widely studied for its role in bone health, immune function, and physical performance. However, its effectiveness is heavily dependent on adequate magnesium status—an interaction that is often overlooked outside of nutritional science.

Magnesium is required to convert vitamin D into its active hormonal form, 1,25-dihydroxyvitamin D. It also helps regulate vitamin D receptor expression, influences binding efficiency at the cellular level, and supports vitamin D transport and metabolism in the liver and kidneys.

From a nutritional education perspective, this is a powerful example of nutrient synergy. High vitamin D intake alone does not guarantee benefit. In fact, vitamin D supplementation in magnesium-deficient individuals may be ineffective and, in some cases, counterproductive.

Understanding these interactions is fundamental for anyone training in nutrition, where the goal is to support whole-body health rather than isolated nutrient targets.

Magnesium’s role in energy metabolism and performance

Magnesium is essential for optimal exercise performance. Research by Nielsen and Lukaski (1) demonstrated magnesium’s role in affecting muscle function, including oxygen uptake, energy production, and electrolyte balance. Importantly, they showed that strenuous exercise increases magnesium loss, potentially raising requirements by 10-20%. They found that athletes who participate in sports that require strict weight control, such as boxing and gymnastics, are at greater risk of an inadequate magnesium status. The authors concluded that providing magnesium supplementation or an increased dietary intake for magnesium-deficient individuals benefits exercise performance.

These recommendations are supported by the findings of Tarsitano et al. (2), which revealed that supplementation with magnesium reduces muscle soreness, improves performance and recovery and induces a protective effect on muscle damage. To achieve these benefits, individuals engaged in intense exercise are advised to maintain a magnesium intake 10–20% higher than their sedentary counterparts. They also advised consuming magnesium 2 hours before exercise.

For nutrition students, this reinforces the importance of contextual intake recommendations. Nutrient needs are not fixed — they change depending on lifestyle, training load, and physiological stress.

Magnesium, hydration, and electrolyte balance

Magnesium works alongside other key electrolytes to improve exercise-related hydration, helping to maintain fluid balance and replace minerals lost through sweat. This helps to ensure muscle function and avoid cramps. Even though many athletes, particularly endurance athletes, suffer from muscle cramps, magnesium is not as common as other electrolytes, such as sodium, in sports drinks.

A study by Kharait (2) examined the effects of magnesium-enriched electrolyte drinks during a half-marathon. Nearly half of the athletes consuming only water experienced muscle cramps, compared to just 21% of those consuming magnesium. Mild to moderate cramps were reported by 12% of athletes hydrating with magnesium, versus 26% in the water only group. Severe cramps were also markedly reduced, falling from 20% in the water group to 9% with magnesium supplementation.

This highlights the importance of balanced electrolyte strategies, rather than focusing on a single mineral.

Optimising muscle growth

Optimising levels of muscle mass not only benefits performance but also health. To do this, anabolic hormones need to be optimised. Magnesium plays a role here, as it’s linked to two anabolic hormones, particularly testosterone and insulin-like growth factor 1 (IGF-1).

Maggio et al., (4) found that magnesium levels are strongly and independently associated with the levels of testosterone and IGF 1 in men. In other words, men with higher magnesium levels tended to have higher testosterone and IGF 1 levels, even after accounting for age.

Although there is an association between testosterone and magnesium, does it mean that increasing magnesium will increase testosterone levels?

According to the results of a study by Cinar and colleagues (5), the answer seems to be yes. These showed that just 4 weeks of supplementation with magnesium increases free and total testosterone levels in both sedentary individuals and athletes, with athletes achieving the greatest gains.

Magnesium and sleep: A foundation of health

Sleep is an essential, yet often overlooked, component of health and well being. It’s also essential for optimising all aspects of performance. While we sleep, our body recovers from the day’s exertions and adapts to the training it has been subjected to. Unfortunately, poor and inadequate sleep is increasingly common, with 62% of adults globally reporting sleep related problems (6). This is associated with increased risk for physical, cognitive and mental health issues, including obesity, diabetes, high blood pressure, cardiovascular disease, depression and dementia. Furthermore, poor sleep quality commonly leads to negative states such as poor mood, greater anxiety and reduced energy and productivity.

A number of studies have demonstrated magnesium’s ability to aid sleep and reduce many of the issues associated with poor sleep. For example, a recent randomised, double blind, placebo controlled trial (6) investigated the effects of supplementary magnesium on sleep quality and daily function in adults with self assessed sleep problems. Over a period of 21 days, subjects consuming magnesium experienced improvements in sleep quality, especially deep/REM sleep stages, improved mood, energy, alertness and daily activity and productivity.

From a nutritional perspective, this underscores how micronutrient adequacy can influence lifestyle factors such as sleep, which in turn affect metabolic health, mental wellbeing, and disease risk.

Achieving the recommended intake

Magnesium is one of seven essential macrominerals, meaning it is required in relatively large amounts. According to UK guidelines:

• Adult men require approximately 300 mg per day
• Adult women require approximately 270 mg per day

While these needs can often be met through a varied diet rich in whole foods, real-world dietary patterns mean this is not always achieved. For nutrition students, learning how to assess intake, recognise risk factors, and recommend appropriate food or supplement strategies is a core professional skill.

Supplementation may be appropriate where intake is insufficient, but excessive intakes should be avoided. Intakes of up to 400 mg per day from supplements are generally considered safe for healthy adults.

Why magnesium matters in nutrition education

Magnesium is a perfect case study for aspiring nutritionists because it demonstrates:

• The complexity of micronutrient function
• The importance of nutrient interactions
• The impact of lifestyle on nutrient requirements
• The need for evidence-based, individualised recommendations

Magnesium plays a vital role in metabolic health, energy production, hormonal balance, sleep, and performance. Despite its availability in common foods, inadequate intake is widespread, particularly in Western diets.

For those considering studying nutrition, magnesium offers a clear example of why understanding nutrients in context — rather than in isolation — is essential. Developing the knowledge to assess, interpret, and apply nutritional science is a key outcome of high-quality nutrition education, and magnesium is an excellent place to start.

References

1) Nielsen FH, Lukaski HC. Update on the relationship between magnesium and exercise. Magnesium Research. 2006;19(3):180–189.

2) Tarsitano MG, Quinzi F, Folino K, Greco F, Oranges FP, Cerulli C, Emerenziani GP. Effects of magnesium supplementation on muscle soreness in different type of physical activities: a systematic review. J Transl Med. 2024 Jul 5;22(1):629. doi: 10.1186/s12967-024-05434-x. PMID: 38970118; PMCID: PMC11227245.

3) Kharait S. A magnesium rich electrolyte hydration mix reduces exercise associated muscle cramps in half marathon runners. J Exerc Nutr. 2022;5(3):12

4) Maggio M, Ceda GP, Lauretani F, Cattabiani C, Avantaggiato E, Morganti S, et al. Magnesium and anabolic hormones in older men. Int J Androl. 2011;34(6 Pt 2):e594 600.

5) Cinar V, Polat Y, Baltaci AK, Mogulkoc R. Effects of magnesium supplementation on testosterone levels of athletes and sedentary subjects at rest and after exhaustion. Biol Trace Elem Res. 2011;140(1):18 23. doi:10.1007/s12011 010 8676 3.

6) NHS. Vitamins and minerals: others [Internet]. London: NHS; c2024 [cited 2026 Jan 7]. Available from: https://www.nhs.uk/conditions/vitamins-and-minerals/others/

Author

Paul Orridge

Paul Orridge BSc (Hons)

Paul Orridge is a graduate in the field of sport, exercise and health, and has over 30 years’ experience within the fitness industry. In this time, he has performed a variety of roles including personal training, lecturing and writing. Paul now works as a freelance technical author and subject matter expert within the fitness industry. His work is based on his practical experience gained working with a diverse range of people from very unfit, overweight individuals to highly conditioned athletes, and is underpinned by the latest research.