Does Magnesium Citrate Cause Cramping?

Difficulty passing stool is an uncomfortable problem that may require a nudge from an over-the-counter laxative. Four types of OTC remedies are available – lubricants, stool softeners, stimulants and osmotic laxatives. According to the University of California, San Francisco, magnesium citrate is an effective osmotic that has the tendency to produce significant cramping.


Magnesium citrate is an oral, non-absorbable, ionic saline laxative. Saline laxatives such as magnesium citrate linger in the colon. As the non-absorbable ions linger, they attract water to the colon and intestines. According to Arkansas Tech University, as the water builds, it increases osmotic pressure within the intestinal walls. This pressure has a stimulating effect on the colon, resulting in peristalsis. Peristalsis moves food through the digestive tract and bowels, sometimes causing cramping.

Stimulatory Effects

If you have constipation, stool is not moving smoothly through your bowels, which means that peristalsis is limited. This forced peristalsis continues as the waste empties into the rectum. Stimulating the muscles of the intestines and rectum in this manner may lead to gas, bloating, diarrhea, nausea and bowel cramping.


Magnesium citrate is a potent laxative, ideally used on an infrequent basis. The Virginia Commonwealth University Wellness Resource Center explains that magnesium citrate may cause severe diarrhea, which may lead to dehydration. Seek medical attention if you experience blood in your stool, unexplained weight loss or abdominal pain while using magnesium citrate to relieve constipation. Constipation that lasts longer than three weeks also warrants a physician’s evaluation. If your kidneys are impaired, it is best to avoid magnesium citrate all together.


Unlike magnesium citrate, some laxatives are safe for use every day. Fiber stool softeners, such as:

  • polycarbophil
  • methylcellulose
  • psyllium
  • oat bran
  • naturally form bulk within the bowels
  • making it easier to pass stool

Taken with 8 oz. of water, fiber stool softeners relieve constipation over a series of days instead of a few hours, which is the case with magnesium citrate. Fiber produces a slower onset of peristalsis, reducing the likelihood of bloating and cramping.