The Ultimate Guide to Magnesium Benefits & Deficiency

Magnesium is one of those nutrients that quietly keeps the body ticking along in the background. It supports everyday functions like muscle movement, energy production and nerve signalling, processes we rely on constantly, even if we don’t always think about them.
 
From helping muscles contract and relax to playing a role in how our bodies manage energy, magnesium is involved in hundreds of biochemical reactions every single day.
 
Despite its importance, magnesium doesn’t always get the attention it deserves. Many people aren’t aware of how much magnesium they need, where it comes from, or what can happen when dietary intake doesn’t meet the body’s needs.
 
This guide brings everything together in one place, explaining what magnesium is, why it matters, how it works in the body, common signs of low intake, and how to support your daily magnesium needs through diet and lifestyle.

See our magnesium buyer's guide for a complete guide on all of the different forms of magnesium available to you!

Magnesium is an essential macro-mineral, which means the body requires it in relatively larger amounts compared to trace minerals like iodine or selenium.
 
It plays a role in more than 300 enzyme-driven reactions that support normal bodily function, including processes related to muscles, nerves, bones and energy metabolism.
 
Because the body cannot produce magnesium on its own, it must be supplied regularly through food, and in some situations, supplementation may be considered.
 
Magnesium is distributed throughout the body, with around half stored in bones and much of the remainder found in muscles and soft tissues. A smaller amount circulates in the blood, where it supports ongoing metabolic activity and helps maintain balance across many interconnected systems.

Magnesium from different foods or supplements may be absorbed differently by the body, which is covered in more detail in our guide to magnesium types.

Magnesium’s benefits come from the many roles it plays at a cellular level. Rather than acting in one specific system, it helps different parts of the body work together efficiently.

Supports Muscle Function

Magnesium plays an important role in normal muscle function by helping regulate muscle contraction and relaxation.
 
It works alongside calcium, which stimulates muscle contraction, while magnesium supports the muscle’s ability to relax again. This balance is essential for smooth, coordinated movement and everyday physical activity.
 
Adequate magnesium intake helps muscles respond appropriately during movement, exercise and rest. When dietary magnesium is low, this balance can be disrupted, which is why magnesium is often brought up in relation to normal muscle function.

Contributes to Energy Production

Every cell in the body relies on energy to carry out its functions, from muscle movement to brain activity. Magnesium is required for the production and activation of ATP (adenosine triphosphate), the molecule that stores and transfers energy within cells.
 
Without sufficient magnesium, ATP cannot be properly activated, meaning energy production may be less efficient at a cellular level.

Supports the Nervous System

Magnesium plays a role in supporting normal nervous system function by helping regulate communication between nerve cells and the brain. It is involved in neurotransmitter activity and helps maintain the balance of signals that travel throughout the nervous system.
 
By supporting these processes, magnesium contributes to the body’s ability to respond to everyday mental and physical demands.

Plays a Role in Bone Health

While calcium is often the first mineral people think of when it comes to bones, magnesium is also an essential part of bone structure. A significant proportion of the body’s magnesium is stored in the bones, where it contributes to mineral balance and structural integrity.
 
Magnesium also supports how calcium and vitamin D are utilised in the body, helping maintain normal bone mineralisation.

Low dietary magnesium intake can develop gradually, which means the early signs are often easy to overlook. Because magnesium supports many different systems in the body, an ongoing shortfall may be reflected in a range of general, non-specific symptoms rather than one clear signal.
 
Low magnesium intake may be associated with symptoms such as muscle tightness, occasional cramps or twitches, general fatigue, or a persistent feeling of low energy.
 
Some people also report changes in mood, such as irritability, or difficulty fully relaxing, particularly in the evening. Sleep patterns may also be affected, as magnesium plays a role in normal nervous system function.
 
Certain lifestyle and dietary factors can increase the likelihood of not meeting magnesium needs. Ongoing stress, regular alcohol consumption, and diets high in refined or sugary foods may contribute to lower magnesium intake. Ageing can also influence magnesium status, as absorption efficiency and dietary intake may change over time.*
 
*These signs are non-specific and can have many causes unrelated to magnesium intake.

Magnesium requirements vary depending on age, sex, and life stage. In Australia, recommended daily intakes are set to support normal physiological function across different stages of life, recognising that needs can change over time.
 
Adult men generally require around 400–420 mg per day, while adult women typically need 310–320 mg per day. During pregnancy, magnesium requirements increase slightly to around 350–360 mg per day to support the additional demands of the body.
 
Children’s magnesium needs vary by age and growth stage, with recommended intakes increasing gradually from early childhood through adolescence.

Always seek advice from a health professional for tailored advice on your magnesium intake.

Magnesium is naturally present in a wide range of everyday foods, particularly those that are whole or minimally processed. Rather than relying on a single ‘superfood,’ regularly including a variety of magnesium-containing foods can help support consistent intake over time.
 
Leafy green vegetables such as spinach and silverbeet are well-known sources, as magnesium is a central component of chlorophyll. Nuts like almonds and cashews, along with seeds, provide magnesium alongside healthy fats and plant-based protein. Whole grains, including brown rice and oats, contribute magnesium as part of their natural mineral content.

Magnesium obtained from food sources is generally well regulated by the body, as excess amounts are typically excreted through normal processes. For this reason, higher magnesium intakes are more commonly associated with non-food sources, such as supplements, rather than diet alone.
 
In some cases, excessive magnesium intake from supplements may affect digestive comfort. Individuals with certain medical conditions, those who are pregnant, or people unsure about their individual magnesium needs should seek personalised advice from a qualified healthcare professional.

Some people may have higher magnesium requirements or may be more likely to fall short through diet alone. Physically active individuals and athletes, for example, may lose magnesium through sweat and have increased nutritional demands to support muscle function and energy metabolism.
 
Older adults may also be at greater risk of lower magnesium intake due to changes in appetite, absorption, or dietary patterns over time. Ongoing stress can influence magnesium use in the body, while certain digestive conditions may affect how well magnesium is absorbed from food.

Magnesium can be obtained through a balanced diet that includes a variety of whole foods, and for some people, supplementation may also be considered to help support intake. Individual needs can vary based on dietary patterns, lifestyle factors, and life stage.
 
For many, focusing on magnesium-rich foods is a practical starting point, while supplements may play a role when dietary intake is inadequate or difficult to maintain.