Magnesium: which type to choose and how much do we really need?
Ayleen Martínez
Orthomolecular Nutritionist
Magnesium has become one of the most popular minerals in supplementation. The interest in it is not just a trend: it is an essential mineral that participates in hundreds of physiological processes related to energy production, neuromuscular function, glucose metabolism, cardiovascular health, bone structure, and nervous system function.
However, the sheer number of available products has also created doubts:
What is the best type of magnesium? Do we need to take 400 mg? Is bisglycinate better than citrate? Does L-threonate really reach the brain? Is oxide useful or not?
The most rigorous answer is that there is no single "best magnesium" for every person and goal. The choice depends on the chemical form, the amount of elemental magnesium, gastrointestinal tolerance, the desired goal, and the available clinical evidence.
Why is magnesium so important? Its main functions
Magnesium is an essential mineral that acts as a cofactor in numerous biochemical reactions.
Among its main functions are:
Energy production
Magnesium participates in the formation and utilization of ATP, the main cellular energy molecule. That is why it is fundamental for energy metabolism.
Muscular and neuromuscular function
It participates in the regulation of neuronal excitability and in the processes of muscle contraction and relaxation. It also maintains a close relationship with calcium.
Cardiovascular system
Magnesium is involved in cardiac muscle function, vascular tone, and electrolyte balance. Recent evidence suggests that supplementation may produce a modest reduction in blood pressure in certain individuals. A meta-analysis of clinical trials found average reductions of nearly 2.8 mmHg in systolic and 2.1 mmHg in diastolic pressure, although results depend on the population and the dose used.
Glucose metabolism
Magnesium participates in mechanisms related to insulin action and glucose metabolism. A review of clinical trials found that supplementation may increase serum magnesium concentrations and produce some favorable effects on metabolic parameters.
Nervous system
It participates in nerve transmission and mechanisms related to NMDA receptors (key for learning, memory, and connecting nerve cells) and neuronal signaling. For this reason, there is growing interest in its relationship with sleep, stress, mood, and cognitive function.
The fundamental difference: elemental magnesium vs. magnesium compound
To understand the different magnesium supplements, you must know a fundamental concept. The body uses magnesium in a form that can participate in different biological functions, but supplements present it bound to different molecules to form different salts or complexes.
For example:
- Magnesium citrate
- Magnesium bisglycinate
- Magnesium L-threonate
- Magnesium acetyl taurate
- Magnesium oxide
The total amount of the compound is not equal to the amount of elemental magnesium.
For example:
2,000 mg of magnesium L-threonate is not 2,000 mg of elemental magnesium.
In studies conducted with Magtein®, 2 g of L-threonate per day provides approximately 145 mg of elemental magnesium. Therefore, when comparing supplements, the most important figure is: How many milligrams of elemental magnesium does the serving actually provide?
What is the difference between the different forms of magnesium?
The molecule to which the magnesium is attached can modify:
- solubility
- gastrointestinal dissolution
- absorption
- digestive tolerance
- elemental magnesium content
- intestinal osmotic effect
A systematic review published in 2021, which analyzed bioavailability studies of different magnesium supplements, found that, in general terms, organic magnesium salts tend to show better absorption than some inorganic forms. Organic forms include citrate, malate, and some amino acid chelated forms, such as bisglycinate. Inorganic forms mainly include magnesium oxide, chloride, sulfate, and carbonate. However, absorption does not depend solely on whether a form is "organic" or "inorganic": dose, compound solubility, formulation, diet, and each individual's characteristics also play a role.
Types of magnesium: bisglycinate, citrate, L-threonate, malate, acetyl-taurate, and oxide
Magnesium bisglycinate
Magnesium bisglycinate is a form where magnesium is bound to two glycine molecules. It is a widely used form due to its good digestive tolerance and has recent clinical evidence studying its potential utility for sleep.
A randomized clinical trial published in 2025 included 155 adults with poor sleep quality. Participants received 250 mg of elemental magnesium daily as bisglycinate for four weeks. The supplemented group showed a significantly greater reduction in insomnia symptoms than the placebo group, although the effect size was small. Therefore, a reasonable statement would be: bisglycinate currently has recent clinical evidence suggesting an improvement in insomnia symptoms in adults with poor sleep quality.
Magnesium citrate
Citrate is one of the forms with the best scientific support regarding absorption.
In a clinical trial, 300 mg/day of elemental magnesium as citrate produced a greater response in different magnesium markers than oxide. Citrate also presented the highest mean serum concentration among the formulations studied. Additionally, citrate has an intestinal osmotic effect, so it may be interesting for people who are simultaneously looking for:
- Magnesium intake
- Good bioavailability
- Support for bowel transit
Because of these characteristics, magnesium citrate is one of the most studied forms and can be a good option for general supplementation, especially when one is also looking to promote bowel transit.
Magnesium L-threonate
L-threonate is probably one of the forms that has generated the most interest due to its research regarding the nervous system, cognition, and sleep.
Unlike other salts, its interest is not primarily in providing large amounts of elemental magnesium, but in investigating whether it can modify the availability of magnesium in the central nervous system. Studies with Magtein® have typically used: 2,000 mg of L-threonate/day ≈ 145 mg of elemental magnesium/day.
A recently published trial studied 2 g daily for six weeks in adults aged 18–45 and evaluated cognition, sleep, and other physiological parameters. Additionally, a trial published in 2024 studied 1 g/day of L-threonate for 21 days in 80 adults with sleep problems and found improvements in certain objective and subjective parameters of sleep and daytime functioning.
Its main particularity is that clinical studies use a relatively low amount of elemental magnesium compared to the usual doses of other salts.
Magnesium malate
Magnesium malate combines magnesium with malic acid, a compound that participates in pathways related to energy metabolism. For this reason, interest has been generated in its possible relationship with energy and fatigue.
This has generated special interest in this form of magnesium in the context of energy, cellular metabolism, and the sensation of fatigue.
Magnesium acetyl-taurate
Acetyl-taurate is a more novel form of special experimental interest. This molecule combines magnesium with N-acetyl-taurine, and its interest is related particularly to the possibility of modifying the distribution of magnesium to tissues such as the nervous system.
There is preclinical research on its distribution and potential neurological and cardiovascular effects.
Recent preclinical studies suggest that magnesium acetyl-taurate could have interesting characteristics for cerebral magnesium availability and neuronal function, including effects on mechanisms related to synaptic plasticity and cognition. However, these results still need confirmation through clinical trials in humans.
Magnesium oxide
Its advantage is that it allows for a large amount of magnesium to be provided with a small amount of raw material.
However, it has lower solubility and relative bioavailability than several organic forms. Comparative studies have found greater availability of citrate and bisglycinate compared to oxide.
This does not mean that magnesium oxide "does not work." Its uses include its application as an antacid to relieve heartburn and indigestion. Furthermore, due to its osmotic effect in the intestine, it can promote bowel transit while providing magnesium to the body. Therefore, it could be useful in certain circumstances, but it is not necessarily the first choice when seeking to maximize absorption or digestive tolerance.
Do you want to know the different forms of magnesium available and choose the one that best fits your goal?
Discover magnesium products →
Discover a triple magnesium with malate, taurate, and bisglycinate, a complete formula with saffron designed to support relaxation, rest, and general well-being within a balanced diet.
More information →Magnesium bioavailability: which form is best absorbed?
Here it is important to avoid one of the most frequent mistakes, since the bioavailability of magnesium depends on multiple factors and there is no single form that can be considered universally superior. Among these factors are:
- Chemical form
- Dose
- Diet
- Age
- Associated pathologies
- Lifestyle
- Measurement method
- Duration of the study
- Marker used
Researchers can measure serum, urinary, erythrocytic, or other parameters depending on the country where the studies are conducted. Therefore, comparing percentages from different studies can hinder an adequate comparison between the different forms of magnesium.
Although a systematic review by Pardo et al. found that, in general, inorganic formulations had lower bioavailability than organic ones. A classic comparative study found that 300 mg/day of elemental magnesium as citrate had greater bioavailability than oxide, while citrate also generated higher serum concentrations.
How much magnesium do we need per day? Recommended daily dose
So, how much magnesium do we really need? Do we all need to supplement with 400 mg a day?
No. This is probably one of the main conclusions that the consumer should know.
Recommendations for total daily intake for adults are approximately:
These figures correspond to the total magnesium intake, including food and supplements. Therefore, it does not mean that every person should supplement with 400 mg of elemental magnesium daily.
This is one of the most common errors in supplementation:
400 mg of recommended daily intake does not mean 400 mg mandatory from a supplement.
In addition, individual needs can vary according to diet, age, physical activity, physiological conditions, among other factors.
Clinical studies use different doses depending on the goal.
For example:
| Form | Studied dose | Elemental magnesium | Goal |
|---|---|---|---|
| Bisglycinate | 250 mg/day | 250 mg | Sleep / insomnia conditions |
| L-threonate | 2,000 mg/day of compound | ≈145 mg | Cognition, sleep, and daytime functioning |
| Citrate | 300 mg/day | 300 mg | Bowel transit and bioavailability |
| Oxide | 400–800 mg/day | 200–400 mg | Acidity and bowel transit |
This demonstrates that there is no magic 400 mg figure associated with all the benefits of magnesium.
Which magnesium should you choose based on your goal?
A practical way to orient yourself is to relate the goal to the available evidence.
For general supplementation
Citrate and bisglycinate have a good track record of use and available evidence, although the choice should be individualized according to each person's characteristics and goals and be evaluated by a nutritionist to determine which is most appropriate based on medical history.
For people with slow bowel transit: Citrate
Its osmotic effect can be useful, although individual tolerance varies.
For sleep: Bisglycinate
There is currently recent clinical evidence using 250 mg/day of elemental magnesium, with a modest improvement in insomnia.
L-threonate also shows interesting results, especially in parameters related to sleep and daytime functioning.
For research related to cognition: L-threonate or Acetyl taurate
This is the form with the most specific interest in this area.
Recent studies have used approximately 1–2 g of the compound, depending on the formulation and protocol.
How to read a magnesium supplement label
When reviewing the label of a magnesium supplement, it is essential to identify how much elemental magnesium each serving provides, as this is the figure that allows for the correct comparison of different products. For example, if a supplement indicates "1,000 mg of magnesium bisglycinate," it does not mean that it contains 1,000 mg of elemental magnesium, but that this is the total amount of the compound. Therefore, the label should clearly identify how many milligrams of elemental magnesium it provides. The way this information is presented may vary according to the regulations of each country, so it is important to review the labeling carefully. When comparing supplements with different forms of magnesium, the relevant factor is to consider the milligrams of elemental magnesium per serving, and not simply the total amount of raw material. It is also advisable to consider the quality and purity of the ingredients, the presence of other compounds, and the product's complete formulation.
Real example · Triple Magnesium nutritional table
Conclusion
Magnesium is an essential mineral that participates in numerous bodily processes related to energy production, muscle and nerve function, metabolism, and cardiovascular health. However, there is no single form of magnesium that is superior for everyone. The choice must consider the chemical form, the amount of elemental magnesium, gastrointestinal tolerance, diet, individual characteristics, and the goal of supplementation.
Similarly, the idea that "everyone needs 400 mg of elemental magnesium per day" should not be interpreted as a universal recommendation for supplementation. Magnesium needs can vary between people, and when there is an indication for supplementation, the most appropriate dose and form will depend on each situation.
For this reason, magnesium supplementation should not be based solely on general recommendations, commercial trends, or choosing the form with the highest number of milligrams. A nutritionist is the ideal professional to evaluate diet, individual needs, and the goal of supplementation, and to determine if there is truly a need for supplementation and which formulation may be most appropriate in each case.
Furthermore, people with kidney disease or impaired renal function should consult a healthcare professional before supplementing with magnesium, as the kidneys play an important role in its elimination.
In short, proper supplementation does not necessarily consist of consuming more magnesium, but of using the appropriate form and dose for each person's needs and goals, with professional guidance.
Ayleen Martínez
Orthomolecular Nutritionist
Bibliography
- Pardo MR et al. Bioavailability of magnesium food supplements: A systematic review. Nutrition, 2021. Systematic review of 14 comparative bioavailability studies.
- Zhang et al. Magnesium Supplementation and Blood Pressure: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. 2025. 38 RCTs, 2,709 participants.
- Magnesium Bisglycinate Supplementation in Healthy Adults Reporting Poor Sleep: A Randomized, Placebo-Controlled Trial. 2025. 155 participants, 250 mg of elemental Mg/day.
- The effects of magnesium L-threonate (Magtein®) on cognitive performance and sleep quality in adults. 2025. 2 g/day of Magtein®.
- Liu et al. A Magtein®, Magnesium L-Threonate, -Based Formula Improves Brain Cognitive Functions in Healthy Chinese Adults. Nutrients, 2022.
- Werner T et al. Assessment of bioavailability of Mg from Mg citrate and Mg oxide.
- Walker AF et al. Mg citrate found more bioavailable than other Mg preparations in a randomised, double-blind study.
- Costello RB et al. A Pilot Randomized Trial of Oral Magnesium Supplementation on Supraventricular Arrhythmias.
- Moabedi M et al. Magnesium supplementation beneficially affects depression in adults with depressive disorder: a systematic review and meta-analysis. 2023.
- Examining the Effects of Supplemental Magnesium on Self-Reported Anxiety and Sleep Quality: A Systematic Review. 2024.
