Few nutrients have generated as much discussion, and confusion, as magnesium. Which form should I be giving to my clients? Why do my clients tolerate one form more than another? Should I recommend bisglycinate for sleep? Threonate for cognition? Malate for fatigue? Taurate for cardiovascular health? Or should I simply choose whichever product provides the highest elemental magnesium? What about avoiding supplements with magnesium oxide? While these questions are widespread, the scientific evidence is more nuanced than many claims suggest.

For practitioners, understanding the chemistry behind magnesium supplements is arguably more important than memorising lists of purported benefits. Once the differences between magnesium salts, chelates, absorption and formulation quality are understood, selecting an evidence-based supplement becomes much simpler.

Why magnesium matters

Magnesium is the fourth most abundant mineral in the human body and serves as a cofactor in over 300 enzymatic reactions, although some estimates place this figure above 600. (Baaj, 2014)

It contributes to:

• normal energy metabolism (ATP production)
• nervous system regulation and psychological function
• muscle contraction and relaxation
• electrolyte balance
• protein synthesis
• DNA and RNA synthesis
• maintenance of normal bones and teeth
• the reduction of tiredness and fatigue.

Approximately 60% of body magnesium is stored within bone, 39% resides inside soft tissues, and less than 1% circulates within the blood. (NIH, 2025) Consequently, serum magnesium often remains normal despite intracellular depletion, making deficiency difficult to detect using routine blood testing.

Are we getting enough magnesium?

The European Food Safety Authority (EFSA) established Adequate Intakes (AIs) for magnesium of 350 mg/day for adult men and 300 mg/day for adult women. In addition, the European Union uses a Nutrient Reference Value (NRV) of 375 mg/day for nutrition labelling purposes. However, the Centre for Magnesium Education and Research suggests that magnesium requirements may be better estimated according to individual body weight. Their recommendation is to multiply body weight in pounds by three to estimate daily magnesium needs. For example, an individual weighing 140lb (approximately 63.5 kg) would require around 420 mg of magnesium per day, from both food and supplements. Food sources of magnesium include pumpkin seeds, almonds, cashews, Brazil nuts, spinach, black beans, lentils, whole grains, dark chocolate and avocado. Despite the availability of these foods, many practitioners will recognise that their clients' dietary magnesium intake frequently falls short of recommended levels.

Modern dietary patterns contain fewer magnesium-rich whole foods, while food processing removes significant quantities from grains. Agricultural practices, declining soil mineral content, and reduced consumption of magnesium-rich foods have all contributed to inadequate magnesium intake. Requirements may also increase in certain circumstances, (Costello, 2016) these include:

• chronic stress
• intense exercise
• gastrointestinal disorders (low stomach acid, dysbiosis, etc) reducing nutrient/magnesium absorption
• medications, such as proton pump inhibitors and certain diuretics
• type 2 diabetes
• excessive alcohol intake
• ageing

Why are there so many different forms of magnesium?

Due to its chemical properties, magnesium in supplements does not exist as pure elemental magnesium. In biological and chemical systems, magnesium is present as the positively charged ion Mg²⁺, which is highly reactive and therefore associates with negatively charged ions or molecules to form stable compounds. These stabilising compounds are either ligands (when directly bound to magnesium) or counter-ions (when they balance charge but are not directly bound). Common forms of supplemental magnesium include magnesium bisglycinate, malate, taurate, threonate, citrate, oxide and chloride.

The ligand and counter-ion determine many characteristics of the finished ingredient, including:

• solubility
• stability
• dissolution rate
• elemental magnesium content
• gastrointestinal tolerance
• manufacturing characteristics.

Importantly, the ligand and counter-ion do not always determine where magnesium travels within the body.

Salts vs chelates

Magnesium supplements broadly fall into two categories:

• Magnesium salts: combine magnesium with organic or inorganic acids, such as citrate, malate or oxide.
• Magnesium chelates: bind magnesium to amino acids, such as glycine, threonate or taurine.

Chelates tend to demonstrate improved gastrointestinal tolerance and often dissolve effectively under physiological conditions. However, both salts and chelates can be effective magnesium sources provided they dissolve adequately within the gastrointestinal tract.

What does ‘fully reacted’ mean and why does it matter?

Another important quality consideration is whether a magnesium ingredient is fully reacted. When a magnesium is ‘fully reacted’ it means the magnesium has been completely bound to its stated ligand or counter-ion during the production of the supplement. If a magnesium is not fully reacted, it means that the magnesium being sold also contains another form, most commonly magnesium oxide. Some manufacturers blend magnesium oxide with amino acids and market the finished material as other forms of magnesium, i.e. magnesium bisglycinate. This practice is commonly, but incorrectly, referred to as buffering, although terminology varies across the industry.

Magnesium oxide contains approximately 60% elemental magnesium, making it a cheap way to increase the elemental magnesium declared on the label. While this does not necessarily make the product ineffective, it may make it less tolerated as compared to a fully reacted form of magnesium bisglycinate, or other forms, without any oxide present.

Does one form work better than another?

There is a common tendency to label different forms of magnesium as having distinct, specialised functions, for example, bisglycinate for sleep, malate for energy, threonate for the brain, taurate for the heart.

There is certainly biological plausibility behind these suggestions, for example:

• malate participates in the Krebs cycle
• taurine has recognised cardiovascular and neurological functions
• glycine possesses calming neurotransmitter activity
• magnesium L-threonate has demonstrated increased brain magnesium concentrations in animal models.

Controversially, human research remains less conclusive. Systematic reviews comparing different magnesium forms generally conclude that total magnesium intake is more influential than the specific form consumed, assuming the supplement is adequately absorbed and well tolerated. (Pardo, 2021) Once magnesium ions are released and absorbed, current human evidence has not demonstrated that one form consistently outperforms another across clinical outcomes, at least as far as magnesium core functions are concerned. However, studies show that certain forms are preferred based on their absorbability, which is dependent on multiple other factors including:

• existing magnesium status (this is probably one of the most important factors in determining how much magnesium is absorbed)
• dissolvability of magnesium in stomach acid
• intestinal health and how effectively magnesium is released and travels across the gut wall
• vitamin D status
• dissolution characteristics of the supplement
• dosage consumed.

While there is some human research showing that magnesium threonate can improve cognitive health in specific individuals, there is little human research showing that other forms of magnesium work better to support the specific functions attributed to them by virtue of their ligand or counter-ion. Nonetheless, we cannot overlook anecdotal evidence that we see in practice, and the scientific plausibility behind assigning specific functions to specific forms.

Further, human studies often rely on blood magnesium levels, which are not a particularly reliable marker of overall magnesium status. More informative measures, such as intracellular magnesium (e.g., in red blood cells) or functional outcomes like cognitive markers, sleep quality and duration, are less commonly assessed.

Ultimately, multiple forms of magnesium can be effective, and while they may differ in their rates of absorption depending on individual physiology, they tend to function similarly once inside the body. The compound magnesium is bound to may contribute additional effects, particularly if it is an amino acid, but this is separate from magnesium’s core role. Importantly, the type of salt or ligand can influence tolerability, which is a key practical consideration when choosing a supplement. While solubility can affect absorption rate, the overall dose of magnesium remains the most critical factor.

Why use a multi-form supplement?

Combining multiple well-absorbed forms offers several practical advantages. Different ligands dissolve at different rates and possess varying gastrointestinal tolerability. Individual clients may therefore absorb certain forms more efficiently than others. A comprehensive formula provides functional diversity while avoiding reliance on a single delivery system.

Our new fully reacted Magnesium Complex brings together four well-characterised forms of magnesium selected for their favourable solubility, tolerability and formulation characteristics.

Magnesium Bisglycinate

A gentle amino acid chelate providing excellent gastrointestinal tolerance and reliable absorption. Glycine itself also contributes to relaxation and sleep physiology. (Inagawa, 2016)

Magnesium Malate

Bound to malic acid, a compound involved in cellular energy metabolism. It is often chosen by practitioners supporting physically active individuals or those experiencing fatigue.

Magnesium Taurate

Combines magnesium with taurine, an amino acid involved in calcium regulation, cardiovascular function and nervous system signalling. (Schaffer, 2018)

Magnesium Threonate

A newer magnesium form that has attracted particular research interest in cognitive health and neurological ageing. Human evidence continues to evolve and preliminary research has generated considerable interest regarding cognitive health and neurological ageing, with it being purported to have a greater ability to cross the blood brain barrier. (Liu, 2015)[CN3.1]

While debates around magnesium forms often dominate the conversation, practitioners may benefit from paying equal attention to formulation quality. Ensuring that magnesium ingredients are fully reacted and transparently labelled can be just as important as the specific form selected. Our Magnesium Complex was formulated with this principle in mind, combining four fully reacted magnesium forms to provide a consistent and transparent source of supplemental magnesium. It has also been formulated with different forms to help clients that may have decision fatigue when trying to work out what form of magnesium they should be taking.

The science of magnesium is undoubtedly intricate and complex, however, choosing the right magnesium supplement does not have to be. Focus on quality, not hype, and remember: a magnesium supplement or complex should support your clients' health, not complicate your decision-making.

References

• Baaij, J. H. F., Hoenderop, J. G. J., & Bindels, R. J. M. (2015). Magnesium in man: implications for health and disease. Physiological Reviews, 95(1), 1–46.
• Costello, R. Wallace, T. and Rosanoff, A. (2016). Magnesium. Advanced in Nutrition. 7(1), 199-201.
• Inagawa, K., et al. (2016). Subjective effects of glycine ingestion before bedtime on sleep quality. Sleep and Biological Rhythms, 4(1), 75–77.
• Liu, G., et al. (2015). Efficacy and Safety of MMFS-01, a Synapse Density Enhancer, for Treating Cognitive Impairment in Older Adults: A Randomized, Double-Blind, Placebo-Controlled Trial. Journal of Alzheimer’s Disease, 49(4), 971–990.
• National Institutes of Health. (2022). Magnesium. National Institutes of Health.
• Pardo, M. R., et al. (2021). Bioavailability of magnesium food supplements: A systematic review. Nutrition (Burbank, Los Angeles County, Calif.), 89, 111294.
• Schaffer, S., & Kim, H. (2018). Effects and Mechanisms of Taurine as a Therapeutic Agent. Biomolecules & Therapeutics, 26(3), 225–241.

All of our blogs are written by our team of expert Nutritional Therapists. If you have questions regarding the topics that have been raised, or any other health matters, please do contact them using the details below:

nutrition@cytoplan.co.uk

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