Why we need magnesium

But while you might know magnesium best for helping to reduce tiredness and fatigue, its relationship with energy goes much deeper than that. So, what exactly does magnesium do – and why does getting enough matter? Let’s take a closer look.

Magnesium is the fourth most abundant mineral in your body. But your body can’t make it, so NHS recommends 300mg a day for men and 270mg a day for women.⁷ There are plenty of foods you can find it in, or if needed, supplementation. It also helps activate more than 300 enzymes, acting a little like a biological ‘switch’ that enables many everyday processes to take place.¹

Feeling energised isn’t just about how much sleep you get or what you eat for breakfast. Behind the scenes, your body relies on a complex network of nutrients and chemical reactions to turn the food you eat into energy your cells can actually use – and magnesium is an important part of this process.¹ While magnesium doesn’t provide energy itself, it helps activate adenosine triphosphate (ATP), the molecule that delivers energy to cells throughout your body. Magnesium binds to ATP to support its function, making it essential for energy production at a cellular level.⁸ In fact, ATP is only biologically active when it’s bound to magnesium. 

So, whether it’s your muscles contracting during exercise or your brain and nervous system carrying out their everyday jobs, magnesium has a fundamental role in helping your cells access and use the energy they need.¹ “Magnesium doesn’t work like a quick energy boost," says Madalena. " Instead, it’s a nutrient the body needs as part of its normal energy-producing processes.¹ So, it’s better to think of magnesium as supporting the machinery behind everyday energy rather than providing energy itself.”

Magnesium is also involved in blood sugar regulation, helping insulin work effectively so glucose can move from your blood into cells, where it can be used for energy.⁹ This means magnesium plays a supporting role in how your body manages and uses glucose. Want to dig deeper? Explore the relationship between magnesium and blood sugar.

Magnesium is in your muscles and joints but it's mostly in your bones, contributing to their normal maintenance and plays a role in how your body processes calcium.^10,11 Long-term magnesium deficiency has been linked with poorer bone health and osteoporosis.¹¹

Every movement you make relies on your muscles contracting and relaxing – and magnesium plays a role in both.^12,13 This could explain why muscle cramps, aches and twitches (like those irritating eye twitches some of us experience) are a common symptom of a magnesium deficiency. Magnesium glycinate may also help relieve constipation, as it helps your digestive muscles and gastrointestinal tract to relax, helping you pass stools more easily.¹⁴

As your heart is one of the most important muscles in the body, it’s no surprise that magnesium supports this organ too.¹⁵ Magnesium contributes to the normal functioning of the nervous system and plays a role in muscle contraction, including the heart muscle, according to current research.¹⁶ Researchers are also exploring the relationship between magnesium status and heart health, with one ongoing study reporting an association between low magnesium and irregular heartbeat.¹⁷

“When we talk about energy, it’s useful to look beyond simply feeling awake or tired," says Madalena. "Magnesium is involved in both energy metabolism and nervous system regulation, so getting enough as part of a balanced diet supports several of the systems we rely on every day.”^1,18,19 The functioning of the nervous system neurotransmission – essentially, the way nerve cells communicate with each other – as well as helping your muscles respond appropriately to nerve signals.¹⁹ 

Magnesium may also support mental wellbeing and stress responses. Want to dig deeper? Explore what the research says about magnesium and mental wellbeing.

“The harmful effects of low magnesium levels won’t happen overnight, but over the years, you might notice a lack of energy, slower muscle repair and weaker bones in later years. If you do have these symptoms, it's important to speak to your doctor so you can get your levels checked and they can rule anything else out.”

Want to learn more? Explore the signs and symptoms of magnesium deficiency.

Research suggests exercise alone may increase magnesium requirements by around 10-20%, with this effect potentially becoming more noticeable when training in the heat.²⁴ Low magnesium levels may also affect exercise tolerance, while getting enough helps support normal muscle function and energy metabolism.²⁴

Want to know more? Find out more about different types of magnesium or check out our list of magnesium supplements.