Last Reviewed:June 20, 2023 by Gabrielle Marks
When referring to intake, magnesium does not cause constipation. In fact, magnesium is often used as a laxative. When referring to deficiency, magnesium can cause constipation if the body is deficient in the mineral. [1]
Jump Ahead
- Magnesium Has a Laxative Effect
- How Magnesium Works to Relieve Constipation
- Calcium Magnesium and Constipation
- Digestive Side Effects of Magnesium
- Glossary of Terms
- Expert Opinion
- Resources
Magnesium Has a Laxative Effect
Dietary magnesium is essential to more than 300 biochemical reactions in the body. Pharmacological magnesium is often recommended or prescribed to correct a deficiency but is also often prescribed as a laxative. [2]
Magnesium citrate is an example of magnesium being used as a laxative. Magnesium citrate is a saline laxative that increases water in the intestines. It is often used medicinally to clean a patient’s bowels before surgery. Another example of magnesium being used as a laxative is magnesium hydroxide, commonly known as Milk of Magnesia, which is often used to alleviate occasional constipation. [3][4]
How Magnesium Works to Relieve Constipation
Magnesium is absorbed in the small intestine. To grasp how magnesium stimulates the digestive tract, it helps to understand how the digestive system works. The small intestine is a tube lined with mucosa. Magnesium is absorbed through the mucosa to the epithelial cells and into the bloodstream. [5] A laxative such as magnesium citrate draws water FROM the tissues INTO the small intestines. This extra water stimulates the forward movement of the intestines. [6]
Calcium Magnesium and Constipation
Because pharmacological magnesium (versus dietary) has a laxative effect, it is often prescribed in addition to calcium supplementation, which can cause constipation. The same concept works in reverse. Calcium supplementation may be prescribed with magnesium supplementation to offset the laxative effect of magnesium. [7]
Digestive Side Effects of Magnesium
Side effects can occur if excessive amounts of pharmacological magnesium are ingested, such as those found in supplements, Epsom salts, or laxatives. The most common side effects are upset stomach, diarrhea, nausea, and vomiting.
More severe side effects include low blood pressure, irregular heartbeat, slowed breathing, confusion, coma, and even death. [8]
Glossary of Terms
- Epithelial cells: a type of cell that covers the inside and outside of the surfaces of your body. They are found on your skin, blood vessels, and organs, including your urinary tract.
Medline Plus - Mucosa: is moist tissue that lines certain parts of the inside of your body. It is in your nose, mouth, lungs, and the urinary and digestive tracts.
Medline Plus - Pharmacological: pertaining to the science of drugs, including their composition, uses, and effects
- Saline: consisting of or containing salt.
Expert Opinion
“It is extremely important that readers speak with their primary care physician before taking supplemental magnesium because it is excreted through the kidneys. If an individual suffers from a kidney disorder, he or she could be at risk for an excess of the mineral in the system.”
Magnesium May Help Constipation Dr. Peter Gott
Resources
- [1] Murakami, K. “Association between dietary fiber, water and magnesium intake and functional constipation among…” European Journal of Clinical Nutrition. 2007; Volume: 61; No: 5; Pages: 616-622.
- [2] Office of Dietary Supplements-National Institutes of Health – “Magnesium.”
- [3] WebMD – “Magnesium Citrate.”
- [4] National Institutes of Health – Medline Plus – “Magnesium Hydroxide.”
- [5] National Institutes of Health – National Digestive Diseases Information Clearinghouse – “Your Digestive System and How It Works.”
- [6] National Institutes of Health – Medline Plus – “Magnesium Citrate.”
- [7] Acu-Cell Nutrition – “Calcium and Magnesium.”
- [8] National Institutes of Health – Medline Plus – “Magnesium.”
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