Magnesium Phosphate Side Effects

Magnesium phosphate is an important mineral, often simply known as magnesium, that helps keep your body working properly. This mineral is involved in more than 300 chemical reactions in your body. It can be used as a laxative for constipation or as an antacid for acid indigestion. Dietary sources of magnesium include whole grains, legumes, broccoli, squash, dairy products and almonds 1. Taking magnesium phosphate has several side effects, and, as with any dietary supplement, your physician should be consulted before use 1.


According to the National Digestive Diseases Information Clearinghouse, diarrhea is one of the possible side effects of magnesium phosphate. During hyperacidity or when the stomach produces excessive amounts of gastric acid, indigestion might occur. The stomach empties at a significantly slower rate, delaying the transport of food to the small intestines. In this situation, antacids are taken to neutralize the acid in the stomach and decrease gastric acid production. Among the common antacids used is magnesium. Aside from neutralizing gastric acid, magnesium phosphate also has a laxative effect, which may lead to diarrhea. Magnesium supplements and magnesium-based products are to be used cautiously to minimize side effects 1.


Vomiting is among the possible side effects of taking magnesium phosphate, as noted by MedlinePlus. Vomiting may be a symptom of several underlying conditions. Pregnant patients and those suffering from motion sickness may throw up. Substances that can irritate the stomach include food, drugs and supplements. Magnesium phosphate may irritate the gastrointestinal tract. When taken in adequate amounts, magnesium is absorbed in the small intestines and excreted through the kidneys.

Abdominal Cramping

According to the Office of Dietary Supplements, abdominal cramping is one of the side effects of magnesium phosphate 1. Abdominal cramping or abdominal discomfort occurs when large doses of magnesium-based supplements are ingested 1. The tolerable upper-limit intake of magnesium for adults 19 years of age and older is 350 mg per day. High amounts of magnesium alter how this mineral gets absorbed and excreted from the body.