You walk into a pharmacy or health-food store looking for magnesium and discover an entire shelf of options.
Magnesium glycinate. Citrate. L-threonate. Taurate. Oxide. Orotate. Aspartate.
Then there are powders, capsules and combination products, all claiming slightly different benefits.
So, which magnesium should you actually choose?
There isn’t one form of magnesium that is best for everyone.
Different magnesium compounds vary in their solubility, absorption, elemental magnesium content and gastrointestinal effects. The right choice depends on why you are taking magnesium, your digestive tolerance, diet, medications, kidney function and overall health.
Let’s look at the differences.
Why Does the Form of Magnesium Matter?
Magnesium in supplements is usually combined with another compound.
For example:
- Magnesium + glycine = magnesium glycinate
- Magnesium + citric acid = magnesium citrate
- Magnesium + taurine = magnesium taurate
- Magnesium + threonic acid = magnesium L-threonate
These different formulations can influence how the supplement behaves within the digestive system and how effectively magnesium is absorbed.
Research comparing magnesium supplements suggests that bioavailability differs between formulations, with several organic magnesium compounds generally demonstrating better bioavailability than magnesium oxide.¹
This is why two bottles that both say “magnesium” on the front may behave quite differently.
What Does “Chelated Magnesium” Mean?
You’ll often see the word chelated on magnesium supplements.
Chelation simply means that the magnesium has been bound to an organic molecule, commonly an amino acid.
Magnesium glycinate, for example, combines magnesium with the amino acid glycine.
Chelation can influence the stability, absorption and gastrointestinal tolerance of a mineral supplement.
But “chelated” doesn’t automatically mean that a product is better for everyone.
The form, dose, elemental magnesium content and reason for taking it still matter.
Magnesium Glycinate: A Popular Choice for Good Gastrointestinal Tolerance
Magnesium glycinate, also called magnesium bisglycinate, combines magnesium with the amino acid glycine.
It is commonly selected when gastrointestinal tolerance is important because it tends to have less of a laxative effect than some other magnesium salts.
This can make it a practical option when magnesium is being considered for:
- General magnesium supplementation
- Muscle tension
- Nervous-system support
- Evening supplementation
- People who don’t tolerate more laxative forms well
Glycine itself also functions as an inhibitory neurotransmitter within the central nervous system.
However, this requires an important distinction.
We shouldn’t assume that all of the independent neurological effects of glycine automatically apply to magnesium glycinate supplementation.
For that reason, rather than describing magnesium glycinate as a “calming magnesium” or a treatment for anxiety or insomnia, I prefer to describe it as a well-tolerated form that may be appropriate when nervous-system and muscular support are clinical priorities.
And if poor sleep or anxiety is persistent, the underlying cause still needs investigation.
Magnesium Citrate: A Good All-Rounder—Especially When Constipation Is Present
Magnesium citrate combines magnesium with citric acid.
It has good water solubility and has demonstrated relatively good bioavailability compared with some other magnesium preparations.²
Magnesium salts can also have an osmotic effect within the bowel, drawing water into the intestinal contents.
This makes citrate particularly useful when someone requires magnesium supplementation and also experiences constipation.
However, the same property can become a disadvantage if bowel motions are already loose.
Higher amounts may cause:
- Loose stools
- Abdominal discomfort
- Urgency
- Diarrhoea
So magnesium citrate may be a good choice when constipation is present, but it isn’t necessarily the ideal form for someone with diarrhoea or a particularly sensitive bowel.
Magnesium L-Threonate: A Form Being Studied for Cognitive Health
Magnesium L-threonate has received considerable attention for its potential neurological applications.
It was developed specifically with the aim of increasing magnesium concentrations within the brain.
Preclinical research suggests that magnesium L-threonate can increase brain magnesium concentrations and has generated interest in areas such as synaptic plasticity, learning and memory.³
Emerging human research is also investigating its potential effects on cognitive function.
However, this remains a developing area of research.
You may have seen claims online that:
“Magnesium L-threonate is the only magnesium that crosses the blood-brain barrier.”
I would be cautious with this statement.
Current evidence does not justify such an absolute claim.
A more accurate description is:
Magnesium L-threonate is a specialised magnesium formulation being investigated for its ability to influence brain magnesium concentrations and cognitive function.
It is also generally considerably more expensive than standard magnesium supplements.
For someone simply wanting to increase magnesium intake or support general muscle and nervous-system function, that additional expense may not be necessary.
Magnesium Taurate: An Emerging Area of Cardiovascular Interest
Magnesium taurate combines magnesium with taurine.
Taurine is an amino-sulfonic acid naturally found throughout the body and has physiological roles relevant to cardiovascular, metabolic and nervous-system function.
Magnesium itself is also important for normal cardiovascular physiology.
Combining these nutrients has therefore generated interest in magnesium taurate for potential cardiovascular and metabolic applications.
However, there is an important difference between a biologically plausible combination and a treatment that has been extensively demonstrated in clinical trials.
At present, direct human evidence demonstrating that magnesium taurate is superior to other well-absorbed forms of magnesium for cardiovascular health remains limited.
I therefore wouldn’t describe magnesium taurate as the magnesium for the heart.
It is better viewed as an interesting specialised formulation for which further clinical research is needed.
Anyone with cardiovascular disease, hypertension or cardiac rhythm abnormalities should also discuss supplementation with an appropriate healthcare practitioner, particularly when prescription medication is being used.
Magnesium Oxide: Poorly Absorbed Doesn’t Mean Useless
Magnesium oxide sometimes gets dismissed as a “bad” magnesium.
That isn’t entirely accurate.
Magnesium oxide contains a relatively high proportion of elemental magnesium, but research suggests that its fractional absorption is relatively low compared with several organic magnesium formulations.¹
For that reason, it is generally not my first choice when the primary objective is systemic magnesium supplementation.
However, lower absorption can be useful for another reason.
Magnesium remaining within the gastrointestinal tract can exert an osmotic effect and draw water into the bowel.
This is why magnesium oxide is commonly used as a laxative for constipation.
So rather than describing magnesium oxide as good or bad, the better question is:
Is it appropriate for what we’re trying to achieve?
For constipation, potentially.
For someone looking specifically for a well-absorbed magnesium supplement, another form may be preferable.
What About Magnesium Orotate?
Magnesium orotate combines magnesium with orotic acid.
It has been investigated for cardiovascular applications and cellular energy metabolism.
However, the evidence base is considerably smaller than the evidence surrounding magnesium supplementation more broadly.
For this reason, I would be cautious about claims that magnesium orotate has a unique affinity for cardiac muscle or provides superior cardiovascular benefits.
It is better regarded as a specialised magnesium formulation with a more limited evidence base.
What About Magnesium Aspartate?
Magnesium aspartate is another magnesium formulation available in some supplements.
It appears to have reasonable bioavailability and can be used as a source of supplemental magnesium.
However, it is less commonly selected than formulations such as citrate or glycinate in many practitioner products.
You may occasionally hear that magnesium aspartate is “stimulating” and should be avoided by sensitive individuals.
At present, I don’t think there is sufficient clinical evidence to make this a general recommendation.
The more important considerations are how much elemental magnesium the product provides, how well it is tolerated and whether it is appropriate for the individual.
Quick Guide: How Do the Different Forms Compare?
| Magnesium form | Common reason it may be considered | What to know |
| Glycinate / bisglycinate | General supplementation, muscle and nervous-system support | Generally well tolerated with less laxative effect than some magnesium salts |
| Citrate | General magnesium support, particularly when constipation is present | Relatively good bioavailability; may loosen stools |
| L-threonate | Cognitive and neurological research applications | Emerging research; specialised and generally more expensive |
| Taurate | Cardiovascular and metabolic research interest | Physiologically interesting, but direct comparative human evidence remains limited |
| Oxide | Constipation | Relatively low fractional absorption but useful osmotic laxative effects |
| Orotate | Specialised cardiovascular applications | Limited evidence compared with magnesium more broadly |
| Aspartate | General magnesium supplementation | Reasonably bioavailable; less commonly used in practitioner formulations |
Don’t Forget About Elemental Magnesium
This is one of the most important things to understand when buying a magnesium supplement.
The total weight of a magnesium compound is not necessarily the amount of actual magnesium you are receiving.
For example, a label may list a large amount of magnesium glycinate compound but provide a much smaller amount of elemental magnesium.
When comparing products, look for the amount labelled:
Magnesium
or
Elemental magnesium
per capsule, tablet, scoop or recommended serving.
This makes comparing different formulations much more meaningful.
How Much Magnesium Do You Need?
Magnesium requirements vary according to age, sex and life stage.
Australian Nutrient Reference Values recommend approximately:
- 310–320 mg per day for most adult women
- 400–420 mg per day for most adult men
Requirements differ during pregnancy and across different age groups.⁴
Importantly, these figures represent total daily magnesium requirements, primarily obtained through food.
They are not recommendations that everyone should take 300–400 mg of supplemental magnesium every day.
Supplementation should be considered according to:
- Dietary intake
- Age
- Health conditions
- Medications
- Kidney function
- Gastrointestinal tolerance
- Reason for supplementation
More isn’t necessarily better.
Can You Get Enough Magnesium From Food?
Before reaching for a supplement, look at your diet.
Magnesium occurs naturally in foods such as:
- Pumpkin seeds
- Chia seeds
- Almonds
- Cashews
- Legumes
- Spinach and other leafy greens
- Avocado
- Whole grains
- Tahini
- Edamame
- Dark chocolate
A simple strategy is to include leafy greens + nuts or seeds + legumes or whole grains most days.
Food provides magnesium alongside fibre, healthy fats, protein, polyphenols and many other important nutrients.
For general health, food should remain the foundation.
When Should You Take Magnesium?
There isn’t necessarily one perfect time.
The timing depends partly on the reason for taking it and the formulation being used.
Magnesium glycinate is often taken in the evening when it forms part of a night-time routine.
Magnesium citrate used for bowel regularity should be adjusted according to bowel response.
Some people tolerate divided doses better than taking a larger amount at once.
Consistency and tolerance are generally more important than chasing the “perfect” time of day.
Can Magnesium Interact With Medication?
Yes.
This is particularly important because magnesium can interfere with the absorption of certain medications when taken at the same time.
Examples include some:
- Antibiotics
- Thyroid medications
- Osteoporosis medications
The amount of time required between medication and magnesium depends on the medication, so check with a pharmacist, GP or other appropriately qualified healthcare practitioner rather than applying one universal timing rule.
Kidney function also matters.
The kidneys are responsible for regulating magnesium and removing excess magnesium from the body.
People with impaired kidney function should seek medical advice before taking therapeutic-dose magnesium supplements.
Can You Take Too Much Magnesium?
Yes.
More magnesium does not necessarily provide more benefit.
Excess supplemental magnesium commonly causes gastrointestinal symptoms such as:
- Diarrhoea
- Abdominal cramping
- Nausea
Very high magnesium concentrations can become medically serious, particularly when kidney function is impaired.
This is another reason I don’t recommend choosing a magnesium product simply because it provides the highest dose.
The goal is to use an appropriate form and dose for the individual.
So, Which Magnesium Is Right for You?
A simple way to think about the different forms is:
Want a generally well-tolerated magnesium with minimal laxative effect?
Magnesium glycinate may be worth considering.
Need magnesium supplementation and also experience constipation?
Magnesium citrate may be particularly useful.
Interested specifically in cognitive health?
Magnesium L-threonate is an interesting specialised formulation, although the evidence is still developing.
Interested in cardiovascular applications?
Magnesium taurate is physiologically interesting, but its clinical evidence shouldn’t be overstated.
Looking primarily for constipation support?
Magnesium oxide can be useful precisely because of its gastrointestinal osmotic effect.
But the most important question may not be:
“Which magnesium is best?”
Instead, ask:
“Why am I taking magnesium in the first place?”
The right supplement depends on the reason for taking it, dietary intake, symptoms, gastrointestinal function, medications, kidney function and overall health.
And sometimes, the best starting point isn’t a supplement at all.
It is increasing leafy greens, legumes, nuts, seeds and other magnesium-rich whole foods.
The Takeaway
Magnesium isn’t just magnesium.
Different formulations have different characteristics, and marketing claims can sometimes move considerably faster than the research.
Magnesium glycinate may be useful when gastrointestinal tolerance is important. Citrate can be particularly practical when constipation is also present. L-threonate is being investigated for cognitive applications. Taurate is an emerging area of cardiovascular interest. Oxide has poorer fractional absorption but remains useful as an osmotic laxative.
The goal isn’t to find the magnesium with the biggest claims.
It is to choose the right form, for the right reason, at the right dose.
If you’re unsure whether magnesium supplementation is appropriate, a naturopathic assessment can review diet, symptoms, medications, gastrointestinal health, kidney function and relevant pathology before recommending an individualised approach.
Missed Part One?
If you missed our first magnesium blog, Are You Getting Enough Magnesium?, click here to learn why magnesium is important for stress, sleep, energy, muscle function and metabolic health.
References
Pardo, M. R., Garicano Vilar, E., San Mauro Martín, I., & Camina Martín, M. A. (2021). Bioavailability of magnesium food supplements: A systematic review. Nutrition, 89, 111294.
Walker, A. F., Marakis, G., Christie, S., & Byng, M. (2003). Mg citrate found more bioavailable than other Mg preparations in a randomised, double-blind study. Magnesium Research, 16(3), 183–191.
Slutsky, I., et al. (2010). Enhancement of learning and memory by elevating brain magnesium. Neuron, 65(2), 165–177.
National Health and Medical Research Council. (2006). Nutrient reference values for Australia and New Zealand including recommended dietary intakes. Australian Government Department of Health and Ageing & New Zealand Ministry of Health.
National Institutes of Health, Office of Dietary Supplements. Magnesium: Fact sheet for health professionals.
RN Labs. (2026, August–September). The magnesium crisis. RN Labs Newsletter.
Clinical framework informed by RN Labs (2026), with clinical claims interpreted alongside published scientific literature and Australian nutrient reference values.
This article is for general educational purposes and does not replace individual medical advice. Speak with an appropriate healthcare practitioner before starting supplementation if you take prescription medication, have impaired kidney function, are pregnant or have a significant medical condition.
