Magnesium Supplements Explained: Types, Benefits and How to Choose the Right Form

With so many supplements on the market promising better energy, improved sleep and reduced stress, it can be hard to know which ones are worth considering. One nutrient that continues to stand out is magnesium, a mineral involved in hundreds of essential processes in the body. 

In this guide, we’ll explain why magnesium is so important, why many people may not be getting enough, and how different forms of magnesium can support everyday wellbeing. 

A Practical Guide to Magnesium, Absorption, Bioavailability and Everyday Wellbeing

Magnesium is an essential mineral that your body needs to function properly. It’s involved in over 300 processes that help keep everything running smoothly, including – 

• Producing energy from the food you eat 
• Supporting your nervous system, helping you to stay calm and balanced 
• Maintaining healthy muscles, including helping them relax 
• Support bones and teeth 
• Helping your body repair and renew cells and more 

Magnesium also plays an important role in brain health. It helps regulate key neurotransmitters, including gamma aminobutyric acid (GABA), often referred to as the body’s ‘calming’ chemical which supports relaxation and a balanced mood. It may also help support a healthy inflammatory response in the brain, which is increasingly recognised as important for long-term cognitive wellbeing. 

Calcium and Magnesium

Magnesium works closely with other minerals, particularly calcium.  

Calcium is often associated with calming because it supports normal nerve function and plays a role in sleep and mood. However, at a cellular level, its role is slightly different – 

• Calcium helps activate the body, triggering nerve signals and muscle contraction
• Magnesium helps the body relax, supporting muscles and the nervous system to switch off. 

You can think of this as a simple balance – 

• Calcium acts as the on switch
• Magnesium acts as the off switch 

For example, when a muscle contracts, calcium moves into the muscle cell to trigger that action. Once the movement is complete, magnesium helps the muscle relax again and return to normal function. 

Magnesium also helps regulate how much calcium enters the cells. When magnesium levels are low, calcium can become more active that it should be which may contribute to muscle tension, cramps or a feeling of being overstimulated. 

This shows, one is not better than the other, it’s about maintaining the right balance between calcium and magnesium so the body can function comfortably. 

Why Many People Don’t Get Enough Magnesium

Magnesium requirements in the UK are guided by the Reference Nutrient Intakes (RNIs), these values represent the average daily intake sufficient to meet the needs of nearly all healthy individuals in a specific age and gender group, based on biochemical, physiological and dietary data. Adults in the UK need around 270-300mg per day, with children 85-200mg per day. 

Magnesium is found in many plant foods such as leafy greens, nuts, seeds and wholegrains. However, in practice many individuals do not reach their daily intake. This is often due the intake of higher processed foods, and many other factors that can affect magnesium levels such as -  

• Stress which increases how many magnesium the body uses 
• Sugar can increase magnesium loss 
• Alcohol impairs absorption and increases excretion 
• Smoking increased oxidative stress, impairs gut absorption of minerals esp magnesium 
• High caffeine intake increase magnesium losses 

It is also worth considering that the mineral content of our food is not what it once was. Changed in soil quality and modern farming methods may reduce the levels of magnesium (along with other minerals) in crops, meaning we may get less from food, even when eating a relatively healthy diet. 

Some commonly used medicines can affect magnesium levels, especially when used long term such as – 

• Antacids and acid blockers (PPIs) 
• Some antibiotics 
• Water tablets (diuretics)
• Digestive and health factors - 

Certain health conditions can make it harder to absorb or retain magnesium – 

• Coeliac disease
• Inflammatory bowel conditions (IBD)
• Diabetes 

When all the above factors are combined, it becomes clear why low or suboptimal magnesium levels relatively common, even if they are not always so obvious.  

It is also important to understand that magnesium levels in the blood don’t’ always reflect what is happening inside the cells. 

Only a very small amount of magnesium circulates in the blood, while the majority is stored inside cells and tissues. This means it’s possible for blood test results to appear ‘normal’ even when over magnesium status is not optimal. 

As a result, some people may still experience symptoms linked to low magnesium, even when standard blood tests don’t show a clear deficiency. 

Signs and symptoms of low magnesium

There can be many signs and symptoms of lower magnesium levels such as – 

• Muscle cramps, spasms or twitching
• Fatigue or low energy
• Anxiety, restlessness or feeling on edge (very common with low magnesium levels)
• Poor sleep or difficulty relaxing
• Sugar cravings esp chocolate
• Brain fog
• Poor blood sugar control
• Memory problems
• Headaches/migraines
• Heart arrhythmias/palpitations
• Fibromyalgia
• Digestive issues such as constipation and more 

Should you consider a supplement?

A balanced diet is always a priority to get your daily intake of magnesium, foods such as dark green leafy vegetables, nuts, seeds, avocado, fish, legumes and whole grains. However, as mentioned above, our magnesium levels depend on other factors such as our lifestyle, medication, absorption etc. 

The global magnesium supplements market size reached USD 1.45 billion in 2024 and is expected to expand with projections indicating it will reach a value of USD 2.76 billion by 2033 (growthmarketreports.com) which reflects the increasing health awareness and requirements of such an important mineral. 

It’s worth noting that not all magnesium supplements are the same, lets look at how to find the best one to suit your needs. 

Choosing a Magnesium Supplement

Supplement labels often list the total weight of the magnesium compound (such as magnesium citrate, glycinate or oxide), rather than just the amount of magnesium itself (elemental magnesium). 

For example, a product may state 500mg of magnesium citrate, but the amount of elemental magnesium, the actual magnesium content may only be around 10-20% of that, providing approximately 50-100mg of magnesium. The remaining weight comes from the carrier molecule (such as citrate or glycine etc) which is necessary for the stability and absorption. This carrier also plays an important role in how well the magnesium is tolerated and absorbed by the body  

Why higher Elemental Weight Isn’t Always Better: Bioavailability Matters

Higher isn’t always better. For example, magnesium oxide provides a high percentage of elemental magnesium, but its poor solubility in water can result in lower absorption. It is also more likely to draw water into the intestines, which explains its common laxative effect. While this can make it useful in certain situations, such as occasional constipation, it may be less suitable for supporting overall magnesium status or broader functions such as energy and metabolic health.  

Chelated or organic forms such as magnesium glycinate, malate and taurate, will contain lower levels of elemental magnesium, however, they are generally better absorbed and often more gently tolerated in the digestive system.  

This is important when it comes to choosing a magnesium supplement, its not just the amount of magnesium available, it is the form that the magnesium is bound to that will show us how much we can absorb and utilise. 

Magnesium supplements come in a variety of forms, each offering different properties in terms of absorption, tolerance and function. Here is a closer look at some of the most commonly chosen types. 

Magnesium Bisglysinate combines magnesium with glycine which is an amino acid which makes it highly bioavailable that can help – 

• Reduce anxiety
• Support blood sugar
• Sleep
• Mood
• Gentle on the stomach, a good choice for those with sensitive digestion.

Magnesium Malate combines magnesium with malic acid which plays a key role in energy production, this form of magnesium can support – 

• Energy and fatigue
• Muscle function
• Daytime where you want to power your energy

Magnesium Taurate combines magnesium with the amino acid taurine that can help support heart & metabolic health as well as nervous system support, it can be considered for -  

• Heart health
• Brain and sleep support – taurine helps calm the brain and help to balance neurotransmitters
• Anxiety and stress 

Magnesium Citrate is a commonly used form of magnesium supplement, it is bound to citric acid, a naturally occurring compounds found in fruits such as citrus fruits. This form dissolves easily in water, which helps make it more available in the body to absorb. Consider the citrate form for – 

• Digestive support and occasional constipation
• Prevention of calcium oxalate kidney stones
• Bone and musculoskeletal support
• Blood sugar support
• Supporting healthy blood pressure