Why Does Magnesium Supplement Cause Diarrhea?

The question of why magnesium supplements cause diarrhea is a situation that many people who use this supplement notice in a short time but often do not fully understand the reason for. Magnesium is an important mineral that plays a role in many vital processes in the body, from muscle and nerve functions to energy production. However, when taken in supplement form, especially if the dosage and form are not chosen correctly, it can have noticeable effects on the digestive system. The most common of these effects is diarrhea. Magnesium has the ability to retain water in the intestines, and this can cause stools to soften or even become watery. This effect appears more quickly, especially in people with sensitive digestive systems.

The Reason Magnesium Supplements Affect the Intestines

The main answer to the question of why magnesium supplements cause diarrhea is related to the osmotic effect of magnesium. Not all of the ingested magnesium can be absorbed in the small intestine. Magnesium that is not absorbed draws water into the intestinal lumen. This increase in water raises stool volume and speeds up bowel movements, resulting in diarrhea. Forms with low absorption rates, such as magnesium oxide, cause this effect more frequently. In addition, taking a high dose of magnesium at once can lead to the intestines retaining more water than they can tolerate. Although this condition is temporary, it can negatively affect daily quality of life.

Which Types of Magnesium Cause More Diarrhea

The type of magnesium supplement directly affects the risk of diarrhea. Forms with low absorption remain longer in the intestines and increase the water-drawing effect. For this reason, some magnesium types are more likely to cause digestive problems than others.
1- Magnesium oxide has a high magnesium content but low absorption, and the likelihood of causing diarrhea is high.
2- Magnesium citrate can speed up bowel movements and show a laxative effect in some people.
3- Magnesium sulfate has a strong bowel-stimulating effect and is generally used for short-term and controlled purposes. In contrast, forms such as magnesium glycinate and magnesium malate are better absorbed and more easily tolerated by the digestive system. Therefore, changing the form often reduces the problem in people who experience diarrhea.

The Effect of Magnesium Overdose and Method of Use

Another important answer to the question of why magnesium supplements cause diarrhea is overdose. Magnesium taken above the daily requirement puts a burden on the intestines when it cannot be absorbed by the body. High doses taken on an empty stomach affect the digestive system even more. In addition, taking the entire dose at once instead of spreading it throughout the day increases the risk of diarrhea. For this reason, it is recommended to take magnesium supplements with meals and divide the dose throughout the day. The correct dose and proper method of use can largely prevent this side effect. / 2025-12-16 09:56:27