Why can magnesium cause diarrhea?

Diarrhea, a common side effect of your dietary supplement , is often a symptom of excess magnesium or general malaise . We'll show you how to avoid this overdose and choose the right solution.

Why can magnesium cause diarrhea?

Diarrhea is often a laxative effect linked to an overconcentration of magnesium in your intestines. This occurs when magnesium absorption is poor (due to an incorrect form of the supplement) or when the dose taken at one time is too high.

A question of intestinal concentration

The body does not always absorb 100% of the magnesium provided by a supplement. The excess that is not absorbed remains in your intestines, creating a high concentration of this mineral.

To dilute this excess and restore balance, your body reacts by drawing water into the intestines. This influx of fluid speeds up transit, softens stools, and can cause the digestive discomfort you're experiencing.

Some forms are more laxative than others

Not all magnesium salts are equally well absorbed. The absorption of magnesium by your body is directly linked to its chemical form. First-generation "inorganic" salts (oxide, sulfate, etc.) are often less well absorbed .

This poor absorption leaves more unabsorbed magnesium in your gut, increasing the risk of adverse effects and gastrointestinal problems. In our opinion, understanding the bioavailability of a salt is key.

Source: Pubmed, 2003

An excessive or poorly distributed dose

Sometimes the problem lies not in the form but in the dose . Taking a large amount all at once can overwhelm your body's absorption capacity. Too much magnesium can cause this laxative effect, even with a high-quality form.

Instead of taking it all at once, dividing your dose into two or three doses throughout the day greatly improves tolerance. This simple habit makes a real difference to your health and helps limit discomfort.

If this digestive discomfort persists despite your adjustments, it is always wise to consult a doctor.

Which forms of magnesium are best tolerated?

For a more comfortable magnesium intake, opt for chelated forms such as bisglycinate or malate . Inorganic salts like oxide or sulfate are often the cause of digestive problems.

Highly assimilable forms

To avoid side effects, the key is to choose a form that your body absorbs easily . In our opinion, the most effective are magnesiums bound to an amino acid (known as "chelated"). They are much gentler on your digestive system.

For muscle benefits, magnesium malate is also an excellent option, very well tolerated by everyone.

Supplements to avoid if you have a sensitive gut

Some supplements, often cheaper ones, use first-generation magnesium salts. Their poor absorption makes them prime candidates for digestive discomfort . This is the case with magnesium oxide, sulfate, and chloride.

Magnesium citrate is a special case. While better absorbed than the others, it still has a noticeable effect on digestion for many. Therefore, it's not the first choice if you already have a known sensitivity.

Your health is our priority. Please note that mineral supplementation is not recommended for anyone with kidney failure without medical advice. Caution is advised when taking magnesium in this context.

How to avoid diarrhea during a magnesium treatment?

To maximize the effectiveness of your treatment without discomfort, start with half a dose for the first few days . Always take your magnesium in the middle of a meal and spread your doses throughout the day rather than all at once.

Your digestive comfort depends as much on how you take your supplement as on the product itself. Here are our practical tips to enjoy all its benefits without any discomfort. In our opinion, these are simple habits to adopt for better tolerance.

The recommended daily intake of magnesium for an adult is 6 mg per kilogram of body weight, or approximately 360 mg/day for a woman weighing 60 kg and 420 mg/day for a man weighing 70 kg. These recommendations are established by ANSES .

The best recommendation is to start slowly. Instead of beginning with the full dose indicated, try half for the first few days. This gives your body time to adjust to the new magnesium intake and regulate its absorption.

Rather than taking your entire daily magnesium intake at once, try splitting the dosage . One capsule in the morning and one in the evening, for example, helps maintain a more stable magnesium level and avoids overloading your digestive system all at once.

Taking your supplement in the middle of a meal is another simple tip. The presence of food slows down the release of magnesium in the intestine. This food will help improve absorption, thus optimizing its effectiveness and limiting any adverse reactions.

Magnesium participates in over 300 enzymatic reactions, and its proper absorption is key. Working in synergy with a diet rich in vitamin B6 can also improve its passage into cells and its usefulness to the body.

These simple steps will help optimize your treatment.

FAQ: Your questions about magnesium and diarrhea

Can you continue taking magnesium after having diarrhea?

Yes, but not right away. In our opinion, the best approach is to take a 24- to 48-hour break to allow your digestive system to calm down. This situation is an opportunity to listen to your body more closely.

Then, ease back into it. Reintroduce your magnesium, preferably a better-tolerated form, starting with half a dose. You can then gradually increase it if all goes well.

Should you stop the treatment if you have diarrhea?

Yes, you should temporarily stop taking it. Consider the diarrhea as a sign: your body is telling you that the current dose or form of the supplement isn't right for you. It's a simple adjustment that needs to be made.

Far from being a failure, this is an opportunity to adapt your treatment to perfectly suit your own digestive sensitivity. It's therefore not a permanent stop, but simply a strategic pause.

Can magnesium from food also cause diarrhea?

This is a very unlikely scenario. The body manages the absorption of minerals from a natural source differently. Foods rich in magnesium, such as spinach, almonds, or dark chocolate, release it slowly.

Unlike a concentrated supplement, absorption is gradual and regulated. The laxative effect is therefore almost exclusively associated with taking dietary supplements when the form or dose is unsuitable.