Magnesium: Understanding the Different Forms and Their Functions
One essential mineral, many different forms. What makes them different, and does the way we use magnesium matter?
Magnesium is one of the most important minerals in the human body, yet it's also one of the most misunderstood.
We hear about magnesium for muscles, sleep, energy, relaxation, digestion and general wellbeing. We see it in nutritional supplements, bath salts, topical preparations and even certain medicines. Have you ever wondered why there are so many different types?
Magnesium sulphate, magnesium chloride, magnesium glycinate, magnesium citrate, magnesium malate... the list goes on. Are they all doing the same thing? Is one better than another? And does magnesium work differently depending on whether we consume it, apply it to our skin or dissolve it in a warm bath?
To answer these questions, it helps to understand magnesium itself before exploring the compounds in which it is found.
What Does Magnesium Actually Do in the Body?
Magnesium is an essential mineral, meaning our bodies require it for normal function but we cannot manufacture it ourselves.
An adult human body contains approximately 25 grams of magnesium. Much of this is stored in our bones, with the remainder distributed throughout our muscles, organs and other tissues. It doesn’t sound like much when we look at our overall weight, but magnesium participates in hundreds of biochemical processes and without enough of it, our body doesn’t function at its best and we will soon start to see signs of ill health.
Some of its most important roles include:
Energy production: Magnesium is essential for processes that allow our cells to produce and use energy, including the functioning of ATP, often described as the body's cellular energy currency. When magnesium levels are too low, we may experience fatigue, weakness and a noticeable lack of energy.
Muscle function: Magnesium helps regulate muscle contraction and relaxation, working alongside minerals such as calcium. A deficiency may contribute to muscle cramps, spasms, twitching or feelings of muscular weakness.
Nervous system function: Magnesium plays an important role in nerve signalling and communication between the brain and body. When levels become too low, we may experience tingling, numbness or unusual muscle twitching. Severe deficiencies can even contribute to seizures.
Bone structure: Magnesium contributes to bone structure and helps regulate processes involved in maintaining bone health. Inadequate magnesium intake over time may negatively affect bone health and contribute to reduced bone density, often without any obvious early symptoms.
Protein and DNA synthesis: Magnesium supports the cellular processes required to manufacture proteins, repair and maintain tissues and produce genetic material. A deficiency can interfere with these essential processes, although there isn't usually one specific symptom that tells us this is happening.
Electrolyte balance: Magnesium helps regulate the movement of potassium and calcium, contributing to normal cellular function and heart rhythm. Significant deficiencies can disrupt electrolyte balance, potentially contributing to muscle weakness, cramps, palpitations or abnormal heart rhythms.
Glucose metabolism: Magnesium participates in enzyme systems involved in how the body processes and uses glucose, including insulin signalling. Low magnesium levels are associated with impaired glucose regulation and insulin resistance, although these changes may develop without noticeable symptoms and don't necessarily mean magnesium deficiency is the underlying cause.
These are well-established biological functions of magnesium. However, an important distinction is that knowing magnesium is essential for a particular function does not automatically mean that taking extra magnesium will improve that function in someone who already has adequate levels. It's also important to understand that not all forms of magnesium are absorbed or used in exactly the same way. The most appropriate form may depend on what we're hoping to achieve, how we're using it and our individual needs.
So, let's take a closer look at the different forms of magnesium, what makes them unique and why these differences matter.
Why Are There So Many Different Forms of Magnesium?
Magnesium is a chemical element, represented by the symbol Mg.
In supplements and other preparations, magnesium is generally present as part of a compound, combined with another substance such as chloride, sulphate, citrate or an amino acid.
These combinations create different magnesium compounds with different physical and chemical properties.
Some dissolve readily in water. Others dissolve less easily. Some are commonly used in oral supplements, while others are better known for their use in bathing, topical preparations or medicines.
When consumed, the amount of magnesium absorbed can depend on the compound, its solubility, the dose, the formulation and the individual's digestive function. A lot to consider, right!?!
Once absorbed and available for normal physiological use, magnesium performs its essential biological roles regardless of which suitable compound supplied it.
This is why understanding the difference between the magnesium itself, the compound carrying it and the method of administration is so valuable.
Exploring the Different Forms of Magnesium
Magnesium Sulphate: Epsom Salts
Magnesium sulphate is perhaps best recognised as Epsom salt, named after Epsom in England, where mineral-rich waters became associated with historical bathing traditions.
It consists of magnesium and sulphate ions and is highly soluble in water.
Common uses include:
• Mineral bathing and soaking rituals
• Certain medically supervised treatments
• Specific pharmaceutical preparations
Magnesium sulphate also has well-established medical applications. For example, pharmaceutical-grade magnesium sulphate is administered intravenously in hospitals to help prevent and treat potentially life-threatening seizures associated with pre-eclampsia and eclampsia during pregnancy. Intravenous magnesium sulphate is sometimes administered before very premature birth to help protect the baby's immature nervous system.
This highlights how the same magnesium compound can have very different applications depending on how it is administered, with intravenous medical treatment being quite different from dissolving Epsom salts in a warm bath.
In bathing, magnesium sulphate is valued for its longstanding association with mineral soaking traditions.
Although research has not yet firmly established that soaking in magnesium sulphate produces a meaningful, measureable increase in the body's magnesium stores through skin absorption, many people describe feeling relaxed, comfortable or refreshed after an Epsom salt bath.
Explore more: Epsom Salts – Their Origins, Composition and Uses.
Magnesium Chloride: Magnesium Flakes
Magnesium chloride combines magnesium with chloride ions.
It dissolves readily in water and is found in mineral-rich natural deposits and brines.
Common uses include:
• Oral magnesium preparations
• Magnesium bath flakes
• Topical magnesium preparations
When taken orally in an appropriate formulation, magnesium chloride is among the forms known to have relatively good bioavailability.
Magnesium chloride flakes are also popular in mineral bathing.
An interesting characteristic of magnesium chloride is that it is hygroscopic, meaning it readily attracts moisture from the surrounding environment. This explains why magnesium flakes can sometimes clump or harden when exposed to humid bathroom conditions. It is a natural property of the compound rather than necessarily a sign of poor quality.
Explore more: Magnesium Chloride Flakes – Understanding This Naturally Occurring Mineral Compound.
Magnesium Glycinate: Magnesium Combined with Glycine
Magnesium glycinate, often called magnesium bisglycinate, combines magnesium with glycine, an amino acid.
It is commonly found in oral nutritional supplements.
Common uses include:
• General magnesium supplementation
• Formulations marketed for relaxation and sleep
• Supplements intended to be well tolerated by the digestive system
Glycine itself participates in several biological processes, including protein synthesis and nervous system signalling. So the theory is that this form of magnesium would add more value to the body than magnesium alone.
Magnesium glycinate is particularly popular in supplements designed to support relaxation and sleep. This interest comes partly from magnesium's important role in normal nervous system function and partly from glycine, an amino acid involved in neurotransmitter activity that has also been studied for its potential influence on sleep.
Interestingly, a 2025 clinical trial found that magnesium bisglycinate supplementation produced modest improvements in self-reported insomnia symptoms over four weeks. While these findings are encouraging, further research is needed to understand whether this particular form offers advantages over other magnesium compounds.
Magnesium glycinate is also generally considered a well-tolerated option, particularly for people who experience digestive discomfort with certain other magnesium supplements.
Magnesium Citrate: Magnesium Combined with Citric Acid
Magnesium citrate is formed from magnesium and citrate, which is derived from citric acid.
It is widely used in oral magnesium supplements because it dissolves relatively well and has demonstrated good absorption compared with some less soluble forms.
Common uses include:
• General magnesium supplementation
• Certain preparations for occasional constipation
• Medically directed bowel preparations
At higher doses, magnesium citrate can draw water into the intestines, producing a laxative effect. For someone experiencing sluggish bowels or occasional constipation, this effect may be desirable. However, for someone who already has regular bowel movements or tends towards loose stools, that same effect could make magnesium citrate a less suitable choice.
This is a great example of how the particular magnesium compound, formulation and dose can influence its effects, and why a supplement that suits one person may not be ideal for another.
Magnesium Malate: Magnesium Combined with Malic Acid
Magnesium malate combines magnesium with malate, a compound associated with malic acid.
Malate participates in the citric acid cycle, one of the extremely important pathways involved in cellular energy production.
Common uses include:
• General magnesium supplementation
• Products marketed for energy and muscle wellbeing
Due to the fact that malate is involved in energy metabolism, magnesium malate is sometimes promoted as particularly beneficial for fatigue or muscle discomfort. As a result of both magnesium and malate being involved in cellular energy production, magnesium malate has become a popular choice in supplements marketed for energy, muscle function and fatigue.
While this combination makes it an interesting option, research is still exploring whether magnesium malate offers any particular advantages over other forms of magnesium in supporting energy levels and muscle wellbeing.
Magnesium Oxide: Magnesium Combined with Oxygen
Magnesium oxide contains a relatively high proportion of elemental magnesium by weight. However, it is less soluble than many other magnesium compounds and generally has a lower rate of absorption when taken orally. Interestingly, this isn't necessarily a disadvantage, as it depends on the intended purpose!
As a result of magnesium oxide having a lower absorption into the body, a greater proportion of magnesium may remain within the digestive tract, causing a potential laxative effect, helping to draw water into the intestines and soften stools. This can make it useful in certain preparations designed to relieve occasional constipation.
Magnesium oxide is also used in some antacid preparations because it can help neutralise stomach acid.
This is another example of why the form of magnesium matters. A compound that may be less efficient at delivering magnesium into the bloodstream can still be useful for its effects within the digestive system.
Other Magnesium Compounds
There are several other forms worth recognising.
Magnesium lactate: Used in oral supplementation and generally considered a reasonably absorbable form.
Magnesium aspartate: Another oral form with evidence of relatively good absorption.
Magnesium taurate: Combines magnesium with taurine and is sometimes marketed for cardiovascular wellbeing, although strong evidence for unique benefits remains limited.
Magnesium L-threonate: Marketed particularly for cognitive function because of interest in its potential effects on magnesium availability in the nervous system. Human research is still developing, and claims of superior cognitive benefits require further investigation.
Magnesium hydroxide: Commonly used in certain antacid and laxative medicines.
Each compound has its own characteristics, but none should automatically be considered superior for every person or every purpose. Hence the reason for helping to educate you by doing this page.
What Does Bioavailability Mean?
Bioavailability describes the extent to which a substance becomes available to the body after administration.
For oral magnesium, absorption occurs primarily through the intestines.
Different magnesium compounds vary in their solubility and absorption, although factors such as the dose, food intake, digestive health and existing magnesium status can also influence how much is absorbed.
One particularly useful term to understand is elemental magnesium. A supplement containing 500 mg of magnesium citrate does not necessarily provide 500 mg of magnesium itself. Much of that weight belongs to the citrate portion of the compound. This is why comparing the amount of elemental magnesium on supplement labels is more useful than simply comparing the total weight of different magnesium compounds.
Oral Magnesium, Topical Magnesium and Magnesium Baths: What's the Difference?
This is where understanding the method of administration becomes particularly important.
Oral Magnesium
Magnesium obtained from food and suitable oral supplements enters the digestive system, where a proportion is absorbed and becomes available for the body's normal physiological functions.
This is a well-established pathway for meeting magnesium requirements.
Topical Magnesium
Topical magnesium products are applied directly to the skin, commonly as magnesium chloride sprays, creams, lotions or gels.
The formulation of these products is an important consideration. The skin has a natural protective barrier, but the combination of ingredients in a topical preparation can influence how substances interact with and penetrate its outer layers.
In our own formulations, we've intentionally selected additional naturally derived ingredients with their potential to support the delivery of other ingredients into the skin in mind. This reflects our philosophy that it's not simply about including an ingredient, but also considering how the ingredients work together within the overall formulation.
Research into the absorption of magnesium through the skin is continuing, particularly regarding how different formulations may influence penetration. While meaningful increases in the body's magnesium levels through topical application have not yet been consistently demonstrated, this remains an interesting area for further investigation.
Despite the ongoing questions surrounding magnesium absorption through the skin, topical magnesium products remain popular among people who enjoy incorporating them into their personal wellbeing and self-care routines.
Magnesium Baths
There's something wonderfully restorative about immersing yourself in a warm mineral bath, particularly at the end of a busy or demanding day.
Magnesium sulphate (Epsom salts) and magnesium chloride (magnesium flakes) dissolve readily into bathwater, allowing us to enjoy a mineral-rich soaking experience that has become a cherished part of many people's self-care rituals.
And there's more to this experience than simply the minerals themselves.
The warmth of the water, the opportunity to relax our muscles, the calming environment and the simple act of setting aside time for ourselves can all contribute to a sense of physical comfort and mental relaxation.
At Dr Kez Chirolab, we're also passionate about being intentional with the ingredients we choose. We love the simplicity of naturally sourced mineral salts and thoughtfully selected additions, without the need for unnecessary fragrances, colours or ingredients.
We believe that what we choose to leave out deserves just as much consideration as what we put in.
When we have the choice between a beautifully simple mineral soak and a bath filled with unnecessary additives, we know which experience we'd prefer!
Ultimately, a warm mineral bath can be so much more than a way to wash away the day. It can be an opportunity to slow down, reconnect with ourselves and create a little space for wellbeing in an otherwise busy world.
If you would like to find our more about our Dr Kez Chirolab magnesium based bathing formulations, click here.
Where Should We Get Our Magnesium?
For most people, food is definitely the preferred starting point.
Magnesium occurs naturally in a wide variety of foods, including:
• Pumpkin seeds, almonds and other nuts and seeds
• Legumes such as lentils and beans
• Wholegrains
• Leafy green vegetables
• Dark chocolate
The amount required varies according to age, sex and life stage.
For Australian adults, the recommended dietary intake generally ranges from 310 to 420 mg per day, depending on age and sex, with different requirements during pregnancy.
Supplements may be appropriate in particular circumstances, but they are not automatically necessary for everyone.
Excessive supplemental magnesium can cause diarrhoea and other adverse effects. People with impaired kidney function or those taking certain medications should seek professional advice before supplementation.
A Final Thought: Understanding Rather Than Assuming
Magnesium is a remarkable mineral. Its involvement in energy production, nerve communication, muscle function, bone structure and hundreds of enzyme systems makes it fundamental to normal human physiology. However, understanding magnesium also means recognising that not every magnesium compound behaves identically and not every method of administration has the same supporting evidence.
Magnesium sulphate in a warm bath, magnesium chloride in a topical preparation and magnesium citrate in an oral supplement may all contain magnesium, but that doesn't make them interchangeable.
At Dr Kez Chirolab, we believe knowledge empowers more intentional choices.
By understanding what an ingredient is, where it comes from, how it is used and what the research tells us, we can make choices that reflect both our personal preferences and our understanding of the body.
Because the more we understand what we're choosing, the more empowered those choices become.
Educational information only. This article is not intended to diagnose or treat a medical condition or replace personalised healthcare advice. Nutritional supplementation and medical use of magnesium should be considered in the context of individual needs, existing conditions and medications.