What is magnesium?
A mineral salt
Magnesium is a mineral salt, like calcium, iron, or potassium. Present in large quantities in the body, it is stored in the bones, muscles, or the liver.
It is excreted by the kidneys, through the urine.
This mineral salt plays various roles in the body:
- it plays a role in nervous system balance. Thus, it reduces stress, supports neuronal activity and relieves sleep disorders ;
- it stimulates immunity by activating antibody production and strengthening natural defenses ;
- it supports muscles and promotes muscle relaxation.
Unfortunately, magnesium stores tend to be depleted quickly.
Many factors, such as intense physical activity or stress, accelerate its elimination. Cases of deficiency are therefore common.
A dietary supplement
Magnesium supplements are used to restore mental well-being, and to reduce stress and anxiety.
It is also useful for sleep problems (insomnia, sleep apnea…) or to support muscle mass gain in athletes.
It is available in capsules, in tablets, in liquid solution, or in powder.
ANSES (French Agency for Food, Environmental and Occupational Health & Safety) recommends an intake of 300 to 380 mg/day for men and women.
It is also found in certain foods: sea lettuce, wakame, wheat bran, cocoa, flax seeds, almonds…
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What are its side effects?
Main side effects
In case of overdose, supplementation can pose a real danger and cause side effects such as:
- hypermagnesemia (excessively high concentration of magnesium in the blood)
- diarrhea
- vomiting
- hypotension
- muscle weakness
- respiratory disorders
Stop taking it and consult a doctor if the side effects do not subside.
Precautions for use
To avoid potential side effects, follow the dosage indicated by the manufacturer.
Take your supplement in several doses throughout the day, preferably with meals for better absorption.
The course should not exceed 3 months.
When is it contraindicated?
In case of kidney disease
People suffering from kidney disease should avoid taking it. If kidney function is impaired, magnesium cannot be properly eliminated.
This is particularly the case in kidney failure. The person is then at risk of hypermagnesemia.
When on medication
People on medication should consult their doctor before taking magnesium. This is to avoid any risk of side effects or interactions.
Indeed, its intake reduces the absorption of certain antibiotics (tetracyclines, nitrofurantoin…) and diuretics (amiloride).
Furthermore, it can interact with medications used to treat osteoporosis (bisphosphonates).

In case of digestive disorders
Because of its laxative effects, its consumption is often associated with diarrhea and stomach aches.
It is therefore not recommended for people suffering from frequent digestive disorders, irritable bowel syndrome, ulcerative colitis or gastritis.

