Which form of magnesium should you choose? Bisglycinate, marine, citrate

Persistent fatigue, muscle cramps, increased stress? These symptoms may be a sign of a magnesium deficiency , a mineral essential for the proper functioning of your body. However, faced with the multitude of supplements available on the market, it is often difficult to find your way around: bisglycinate, citrate, marine magnesium... Which form should you choose for optimal assimilation and which types should you avoid?

Faced with this situation, supplementation becomes an effective solution. But not all forms of magnesium are equal. Some are well absorbed and well tolerated by the body, while others can cause digestive problems or have poor bioavailability. This article will guide you through understanding the differences between the main forms of magnesium and choosing the one that best suits your needs.

Also read : how to increase your magnesium intake?

Magnesium: a mineral essential to the body

Magnesium is involved in essential biological functions. It is involved in the production of ATP (adenosine triphosphate), the molecule that provides energy to cells (2). It regulates the activity of calcium channels, directly influencing the transmission of nerve impulses and muscle contraction (3).

Its role in muscle relaxation and cramp prevention is particularly important for athletes and people prone to muscle spasms. In addition, it modulates neurotransmitter activity, reducing neuronal excitability and promoting better stress management and restful sleep (4).

Daily needs and deficiency risks

Nutritional recommendations vary depending on age, gender, and physiological needs. The recommended daily intake (RDI) is on average 400 mg for an adult man and 310 mg for an adult woman (5) . These needs increase:

• In pregnant women for fetal development.
• In the elderly, whose intestinal absorption decreases.
• In athletes, due to increased losses through perspiration (6).
• In stressed people, because the body consumes more magnesium in stressful situations

On a daily basis, more than 70% of French people have an insufficient intake of magnesium , in particular due to a modern diet poor in whole grains, dried vegetables and oilseeds (7).

🔎 Also read : Magnesium: How do you recognize a deficiency?

How is magnesium absorbed by the body?

Magnesium absorption occurs in the small intestine , mainly by two mechanisms:

• An active but saturable mechanism (with limited capacity)
• A passive absorption , slower but not saturable, dependent on the solubility of the magnesium salt present (8).

Bioavailability depends mainly on the chemical form of magnesium. Organic salts (such as bisglycinate or citrate) are better absorbed, while inorganic salts (such as oxide or chloride) have a reduced absorption rate (9).

Why do some forms of magnesium cause digestive problems?

Some forms of magnesium are less well tolerated by the digestive system, mainly due to their low solubility or osmotic effect .

Low solubility: Magnesium oxide, for example, has an absorption rate of less than 10%. Much of it remains in the intestine and attracts water, resulting in a laxative effect (10).

Osmotic effect : Magnesium chloride and sulfate promote water accumulation in the intestine, causing bloating and diarrhea. This is why they are sometimes used as medical laxatives (11).

To avoid these inconveniences, it is preferable to opt for highly bioavailable forms, such as bisglycinate or citrate, which are better absorbed and better tolerated (12).

The most common forms of magnesium (Bisglycinate, marine, citrate)

In the food supplement market, 3 forms of magnesium are particularly used.

Magnesium Bisglycinate: the best assimilated form

Magnesium bisglycinate is a chelated form, where the magnesium ion is bound to two glycine molecules. This structure allows for excellent intestinal absorption and reduces digestive upset. It is particularly suitable for people who are stressed or suffer from chronic fatigue (13).

Marine magnesium: a natural source but poorly assimilated

Marine magnesium , although natural, contains mainly magnesium chloride and oxide, two forms which have the advantage of being very concentrated in elemental magnesium but which are poorly absorbed by the body . It can cause laxative effects if consumed in high quantities (14).

Magnesium Citrate: an interesting alternative

Magnesium citrate has good absorption and is often used for its energizing effects. However, its mild laxative action is a drawback (15).

Forms of magnesium to avoid: oxide, chloride, lactate

Not all forms of magnesium are equal in terms of bioavailability and digestive tolerance . Some forms are poorly absorbed by the body and can cause unwanted side effects. Here are some that are best avoided.

Magnesium oxide: very low absorption

Magnesium oxide is often used in dietary supplements due to its high elemental magnesium content (approximately 60%). However, this concentration does not guarantee optimal absorption.

Studies have shown that only 4-10% of magnesium oxide is absorbed by the small intestine (1). Its low water solubility prevents proper diffusion of magnesium throughout the body, making it ineffective in correcting a deficiency.

Additionally, magnesium oxide remains largely unabsorbed in the intestine, which promotes its laxative effect by drawing water into the intestinal lumen. This can lead to diarrhea or bloating in some sensitive individuals. However, it remains an attractive and affordable solution for taking moderate doses to avoid intestinal discomfort (2).

Magnesium chloride: stomach irritant

Magnesium chloride is a commonly used form in the form of an oral solution (Nigari) or powder diluted in water. It is relatively well absorbed but has several drawbacks.

First, its extremely bitter and unpleasant taste makes it difficult to consume on a regular basis. Second, it is very irritating to the gastric mucosa, which can cause abdominal pain and digestive disorders (3).

Additionally, due to its strong osmotic effect, magnesium chloride can cause loose stools and a marked laxative effect, making it unsuitable for daily supplementation for many people (4).

Magnesium lactate: avoid in case of lactose intolerance

Magnesium lactate is sometimes used as a source of magnesium, particularly in some medications and dietary supplements. Although it is well absorbed, it is not suitable for everyone.

It is derived from lactic acid, which means it may cause digestive discomfort in people with dairy sensitivities or lactose intolerance.

Additionally, in individuals with kidney disorders, lactate accumulation may have adverse effects on acid-base metabolism, warranting caution in its use (5).

How is magnesium bisglycinate formed?

As explained earlier, magnesium bisglycinate is a chelated form of magnesium, meaning it is bound to two molecules of glycine, an amino acid.

To achieve this, it is necessary to carry out "chelation" . In fact, magnesium (often in its oxide form) will react with glycine to form a stable bisglycinate-magnesium complex.

However, this reaction is never 100% complete : a fraction of the initial magnesium may not be fully complexed with glycine, leaving a residual trace of magnesium oxide in the final product. This presence is natural and unavoidable in the bisglycinate manufacturing process, but it remains minimal and does not alter the benefits of this form of magnesium.

Standard magnesium bisglycinate vs. buffered bisglycinate

It is important to differentiate standard bisglycinate from buffered bisglycinate .

A standard magnesium bisglycinate contains a very small proportion of residual oxide, resulting solely from the manufacturing process, without intentional addition.

A buffered bisglycinate , on the other hand, is intentionally enriched with magnesium oxide after chelation. This method increases the elemental magnesium content of the finished product, but it also reduces bioavailability and can lead to laxative effects, as magnesium oxide is poorly absorbed by the body.

Therefore, we will favor an unbuffered bisglycinate because the absence of addition of oxide after manufacturing guarantees a highly bioavailable product that is well tolerated by the body.

Our solution: a magnesium bisglycinate supplement, unbuffered with zinc and vitamin B6

To ensure optimal absorption without digestive discomfort, we have formulated a supplement combining magnesium bisglycinate, zinc and vitamin B6.

The magnesium bisglycinate we have selected is an unbuffered form and is associated with zinc, also in the bisglycinate form.

Zinc plays an important role in the regulation of oxidative stress and immune function, in synergy with magnesium (7).

Vitamin B6 is essential for the absorption and cellular utilization of magnesium. It potentiates its effects on stress management and muscle relaxation (8).

This trio of active ingredients provides effective, well-tolerated and scientifically optimized supplementation to meet daily magnesium needs.

What precautions should I take before taking a magnesium supplement?

Before starting magnesium supplementation, it is important to consider certain factors in order to maximize its effectiveness and avoid unwanted interactions.

Be careful to avoid taking magnesium and calcium at the same time , as these two minerals compete for absorption in the intestine. Excess calcium can reduce the absorption of magnesium, and vice versa (9). Therefore, it is best to space their intake by a few hours.

Be careful of drug interactions as magnesium can interfere with certain antibiotics (tetracyclines, fluoroquinolones), diuretics and proton pump inhibitors (PPIs). In case of medical treatment, professional advice is recommended (10).

And finally, divide the doses for better absorption : instead of a single high-dose intake, it is advisable to divide the supplementation into several small doses throughout the day in order to optimize its assimilation and avoid any digestive discomfort (11).

Conclusion: Bisglycinate, the best form of magnesium to choose

Magnesium is an essential mineral involved in many physiological functions, but its absorption depends largely on the form in which it is consumed. While some forms, such as magnesium oxide, chloride, or lactate, are less absorbable and can cause digestive problems, others, such as bisglycinate and citrate, offer high bioavailability and better intestinal tolerance.

For effective supplementation, magnesium bisglycinate remains the preferred choice. At Argalys, this is the form we have chosen for our magnesium supplement.

Bibliography

1.    Volpe SL. Magnesium in disease prevention and overall health. Advances in Nutrition. 2013;4(3):378-383.

2.    Rude RK. Magnesium deficiency: a cause of heterogeneous disease in humans. Journal of Bone and Mineral Research. 1998;13(4):749-758.

3.    Barbagallo M, Dominguez LJ. Magnesium and aging. Current Pharmaceutical Design. 2010;16(7):832-839.

4.    Institute of Medicine (US) Panel on Micronutrients. Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride. National Academies Press (US); 1997.

5.    Rosanoff A, Weaver CM, Rude RK. Magnesium and public health: the impact of the current dietary intake on disease risk in the United States. Nutrition Reviews. 2012;70(3):153-164.

6.    DiNicolantonio JJ, O'Keefe JH, Wilson W. Magnesium in clinical medicine. Journal of the American College of Nutrition. 2018;37(3):245-260.

7.    EFSA Panel on Dietetic Products, Nutrition and Allergies. Scientific opinion on dietary reference values for magnesium. EFSA Journal. 2015;13(7):4186.

8.    Costello RB, Nielsen F, Coughlin J. Impact of magnesium supplementation on glucose and insulin metabolism. Current Opinion in Clinical Nutrition and Metabolic Care. 2016;19(6):469-474.

9.    Firoz M, Graber M. Bioavailability of US commercial magnesium preparations. Magnesium Research. 2001;14(4):257-262.

10. Schuchardt JP, Hahn A. Intestinal absorption and factors influencing bioavailability of magnesium—an update. Current Nutrition & Food Science. 2017;13(4):260-278.

11. Gröber U, Schmidt J, Kisters K. Magnesium in prevention and therapy. Nutrients. 2015;7(9):8199-8226.